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  • richardmitnick 8:52 pm on September 14, 2022 Permalink | Reply
    Tags: "It's a Planet:: New Evidence of Baby Planet in the Making", ALMA, Astronomers have developed a new technique to identify small planets hidden in protoplanetary disks., , , , ,   

    From The Harvard-Smithsonian Center for Astrophysics: “It’s a Planet:: New Evidence of Baby Planet in the Making” 

    From The Harvard-Smithsonian Center for Astrophysics

    9.14.22

    Astronomers have developed a new technique to identify small planets hidden in protoplanetary disks.

    1
    Credit: M.Weiss/Center for Astrophysics | Harvard & Smithsonian.

    Astronomers agree that planets are born in protoplanetary disks — rings of dust and gas that surround young, newborn stars. While hundreds of these disks have been spotted throughout the universe, observations of actual planetary birth and formation have proved difficult within these environments.

    Now, astronomers at the Center for Astrophysics | Harvard & Smithsonian have developed a new way to detect these elusive newborn planets — and with it, “smoking gun” evidence of a small Neptune or Saturn-like planet lurking in a disk. The results are described today in The Astrophysical Journal Letters [below].

    “Directly detecting young planets is very challenging and has so far only been successful in one or two cases,” says Feng Long, a postdoctoral fellow at the Center for Astrophysics who led the new study. “The planets are always too faint for us to see because they’re embedded in thick layers of gas and dust.”

    Scientists instead must hunt for clues to infer a planet is developing beneath the dust.

    “In the past few years, we’ve seen many structures pop up on disks that we think are caused by a planet’s presence, but it could be caused by something else, too” Long says. “We need new techniques to look at and support that a planet is there.”

    For her study, Long decided to re-examine a protoplanetary disk known as LkCa 15. Located 518 light years away, the disk sits in the Taurus constellation on the sky. Scientists previously reported [Astronomy & Astrophysics (below)] evidence for planet formation in the disk using observations with the ALMA Observatory.

    Long dove into new high-resolution ALMA data on LkCa 15, obtained primarily in 2019, and discovered two faint features that had not previously been detected.

    About 42 astronomical units out from the star — or 42 times the distance Earth is from the Sun — Long discovered a dusty ring with two separate and bright bunches of material orbiting within it. The material took the shape of a small clump and a larger arc, and were separated by 120 degrees.

    Long examined the scenario with computer models to figure out what was causing the buildup of material and learned that their size and locations matched the model for the presence of a planet.

    “This arc and clump are separated by about 120 degrees,” she says. “That degree of separation doesn’t just happen — it’s important mathematically.”

    Long points to positions in space known as Lagrange points, where two bodies in motion — such as a star and orbiting planet — produce enhanced regions of attraction around them where matter may accumulate.

    “We’re seeing that this material is not just floating around freely, it’s stable and has a preference where it wants to be located based on physics and the objects involved,” Long explains.

    In this case, the arc and clump of material Long detected are located at the L4 and L5 Lagrange points. Hidden 60 degrees between them is a small planet causing the accumulation of dust at points L4 and L5.

    The results show the planet is roughly the size of Neptune or Saturn, and around one to three million years old. (That’s relatively young when it comes to planets.)

    Directly imaging the small, newborn planet may not be possible any time soon due to technology constraints, but Long believes further ALMA observations of LkCa 15 can provide additional evidence supporting her planetary discovery.

    She also hopes her new approach for detecting planets — with material preferentially accumulating at Lagrange points — will be utilized in the future by astronomers.

    “I do hope this method can be widely adopted in the future,” she says. “The only caveat is that this requires very deep data as the signal is weak.”

    Long recently completed her postdoctoral fellowship at the Center for Astrophysics and will join the University of Arizona as a NASA Hubble Fellow this September.

    Co-authors on the study are Sean Andrews, Chunhua Qi, David Wilner and Karin Oberg of the CfA; Shangjia Zhang and Zhaohuan Zhu of the University of Nevada; Myriam Benisty of the University of Grenoble; Stefano Facchini of the University of Milan; Andrea Isella of Rice University; Jaehan Bae of the University of Florida; Jane Huang of the University of Michigan and Ryan Loomis of the National Radio Astronomy Observatory.

    This study involved high resolution ALMA observations taken with Band 6 (1.3mm) and Band 7 (0.88mm) receivers.

    Science papers:
    The Astrophysical Journal Letters 2022
    Astronomy & Astrophysics 2020

    See the full article here .


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    Please help promote STEM in your local schools.


    Stem Education Coalition

    The The Harvard-Smithsonian Center for Astrophysics combines the resources and research facilities of the Harvard College Observatory and the Smithsonian Astrophysical Observatory under a single director to pursue studies of those basic physical processes that determine the nature and evolution of the universe. The Smithsonian Astrophysical Observatory is a bureau of the Smithsonian Institution, founded in 1890. The Harvard College Observatory, founded in 1839, is a research institution of the Faculty of Arts and Sciences, Harvard University, and provides facilities and substantial other support for teaching activities of the Department of Astronomy.

    Founded in 1973 and headquartered in Cambridge, Massachusetts, the CfA leads a broad program of research in astronomy, astrophysics, Earth and space sciences, as well as science education. The CfA either leads or participates in the development and operations of more than fifteen ground- and space-based astronomical research observatories across the electromagnetic spectrum, including the forthcoming Giant Magellan Telescope(CL) and the Chandra X-ray Observatory, one of NASA’s Great Observatories.

    GMT Giant Magellan Telescope(CL) 21 meters, to be at the Carnegie Institution for Science’s NSF NOIRLab NOAO Las Campanas Observatory(CL) some 115 km (71 mi) north-northeast of La Serena, Chile, over 2,500 m (8,200 ft) high.

    National Aeronautics and Space Administration Chandra X-ray telescope.

    Hosting more than 850 scientists, engineers, and support staff, the CfA is among the largest astronomical research institutes in the world. Its projects have included Nobel Prize-winning advances in cosmology and high energy astrophysics, the discovery of many exoplanets, and the first image of a black hole. The CfA also serves a major role in the global astrophysics research community: the CfA’s Astrophysics Data System, for example, has been universally adopted as the world’s online database of astronomy and physics papers. Known for most of its history as the “Harvard-Smithsonian Center for Astrophysics”, the CfA rebranded in 2018 to its current name in an effort to reflect its unique status as a joint collaboration between Harvard University and the Smithsonian Institution. The CfA’s current Director (since 2004) is Charles R. Alcock, who succeeds Irwin I. Shapiro (Director from 1982 to 2004) and George B. Field (Director from 1973 to 1982).

    The Center for Astrophysics | Harvard & Smithsonian is not formally an independent legal organization, but rather an institutional entity operated under a Memorandum of Understanding between Harvard University and the Smithsonian Institution. This collaboration was formalized on July 1, 1973, with the goal of coordinating the related research activities of the Harvard College Observatory (HCO) and the Smithsonian Astrophysical Observatory (SAO) under the leadership of a single Director, and housed within the same complex of buildings on the Harvard campus in Cambridge, Massachusetts. The CfA’s history is therefore also that of the two fully independent organizations that comprise it. With a combined lifetime of more than 300 years, HCO and SAO have been host to major milestones in astronomical history that predate the CfA’s founding.

    History of the Smithsonian Astrophysical Observatory (SAO)

    Samuel Pierpont Langley, the third Secretary of the Smithsonian, founded the Smithsonian Astrophysical Observatory on the south yard of the Smithsonian Castle (on the U.S. National Mall) on March 1,1890. The Astrophysical Observatory’s initial, primary purpose was to “record the amount and character of the Sun’s heat”. Charles Greeley Abbot was named SAO’s first director, and the observatory operated solar telescopes to take daily measurements of the Sun’s intensity in different regions of the optical electromagnetic spectrum. In doing so, the observatory enabled Abbot to make critical refinements to the Solar constant, as well as to serendipitously discover Solar variability. It is likely that SAO’s early history as a solar observatory was part of the inspiration behind the Smithsonian’s “sunburst” logo, designed in 1965 by Crimilda Pontes.

    In 1955, the scientific headquarters of SAO moved from Washington, D.C. to Cambridge, Massachusetts to affiliate with the Harvard College Observatory (HCO). Fred Lawrence Whipple, then the chairman of the Harvard Astronomy Department, was named the new director of SAO. The collaborative relationship between SAO and HCO therefore predates the official creation of the CfA by 18 years. SAO’s move to Harvard’s campus also resulted in a rapid expansion of its research program. Following the launch of Sputnik (the world’s first human-made satellite) in 1957, SAO accepted a national challenge to create a worldwide satellite-tracking network, collaborating with the United States Air Force on Project Space Track.

    With the creation of National Aeronautics and Space Administration the following year and throughout the space race, SAO led major efforts in the development of orbiting observatories and large ground-based telescopes, laboratory and theoretical astrophysics, as well as the application of computers to astrophysical problems.

    History of Harvard College Observatory (HCO)

    Partly in response to renewed public interest in astronomy following the 1835 return of Halley’s Comet, the Harvard College Observatory was founded in 1839, when the Harvard Corporation appointed William Cranch Bond as an “Astronomical Observer to the University”. For its first four years of operation, the observatory was situated at the Dana-Palmer House (where Bond also resided) near Harvard Yard, and consisted of little more than three small telescopes and an astronomical clock. In his 1840 book recounting the history of the college, then Harvard President Josiah Quincy III noted that “…there is wanted a reflecting telescope equatorially mounted…”. This telescope, the 15-inch “Great Refractor”, opened seven years later (in 1847) at the top of Observatory Hill in Cambridge (where it still exists today, housed in the oldest of the CfA’s complex of buildings). The telescope was the largest in the United States from 1847 until 1867. William Bond and pioneer photographer John Adams Whipple used the Great Refractor to produce the first clear Daguerrotypes of the Moon (winning them an award at the 1851 Great Exhibition in London). Bond and his son, George Phillips Bond (the second Director of HCO), used it to discover Saturn’s 8th moon, Hyperion (which was also independently discovered by William Lassell).

    Under the directorship of Edward Charles Pickering from 1877 to 1919, the observatory became the world’s major producer of stellar spectra and magnitudes, established an observing station in Peru, and applied mass-production methods to the analysis of data. It was during this time that HCO became host to a series of major discoveries in astronomical history, powered by the Observatory’s so-called “Computers” (women hired by Pickering as skilled workers to process astronomical data). These “Computers” included Williamina Fleming; Annie Jump Cannon; Henrietta Swan Leavitt; Florence Cushman; and Antonia Maury, all widely recognized today as major figures in scientific history. Henrietta Swan Leavitt, for example, discovered the so-called period-luminosity relation for Classical Cepheid variable stars, establishing the first major “standard candle” with which to measure the distance to galaxies. Now called “Leavitt’s Law”, the discovery is regarded as one of the most foundational and important in the history of astronomy; astronomers like Edwin Hubble, for example, would later use Leavitt’s Law to establish that the Universe is expanding, the primary piece of evidence for the Big Bang model.

    Upon Pickering’s retirement in 1921, the Directorship of HCO fell to Harlow Shapley (a major participant in the so-called “Great Debate” of 1920). This era of the observatory was made famous by the work of Cecelia Payne-Gaposchkin, who became the first woman to earn a Ph.D. in astronomy from Radcliffe College (a short walk from the Observatory). Payne-Gapochkin’s 1925 thesis proposed that stars were composed primarily of hydrogen and helium, an idea thought ridiculous at the time. Between Shapley’s tenure and the formation of the CfA, the observatory was directed by Donald H. Menzel and then Leo Goldberg, both of whom maintained widely recognized programs in solar and stellar astrophysics. Menzel played a major role in encouraging the Smithsonian Astrophysical Observatory to move to Cambridge and collaborate more closely with HCO.

    Joint history as the Center for Astrophysics (CfA)

    The collaborative foundation for what would ultimately give rise to the Center for Astrophysics began with SAO’s move to Cambridge in 1955. Fred Whipple, who was already chair of the Harvard Astronomy Department (housed within HCO since 1931), was named SAO’s new director at the start of this new era; an early test of the model for a unified Directorship across HCO and SAO. The following 18 years would see the two independent entities merge ever closer together, operating effectively (but informally) as one large research center.

    This joint relationship was formalized as the new Harvard–Smithsonian Center for Astrophysics on July 1, 1973. George B. Field, then affiliated with University of California- Berkeley, was appointed as its first Director. That same year, a new astronomical journal, the CfA Preprint Series was created, and a CfA/SAO instrument flying aboard Skylab discovered coronal holes on the Sun. The founding of the CfA also coincided with the birth of X-ray astronomy as a new, major field that was largely dominated by CfA scientists in its early years. Riccardo Giacconi, regarded as the “father of X-ray astronomy”, founded the High Energy Astrophysics Division within the new CfA by moving most of his research group (then at American Sciences and Engineering) to SAO in 1973. That group would later go on to launch the Einstein Observatory (the first imaging X-ray telescope) in 1976, and ultimately lead the proposals and development of what would become the Chandra X-ray Observatory. Chandra, the second of NASA’s Great Observatories and still the most powerful X-ray telescope in history, continues operations today as part of the CfA’s Chandra X-ray Center. Giacconi would later win the 2002 Nobel Prize in Physics for his foundational work in X-ray astronomy.

    Shortly after the launch of the Einstein Observatory, the CfA’s Steven Weinberg won the 1979 Nobel Prize in Physics for his work on electroweak unification. The following decade saw the start of the landmark CfA Redshift Survey (the first attempt to map the large scale structure of the Universe), as well as the release of the Field Report, a highly influential Astronomy & Astrophysics Decadal Survey chaired by the outgoing CfA Director George Field. He would be replaced in 1982 by Irwin Shapiro, who during his tenure as Director (1982 to 2004) oversaw the expansion of the CfA’s observing facilities around the world.

    Harvard Smithsonian Center for Astrophysics Fred Lawrence Whipple Observatory located near Amado, Arizona on the slopes of Mount Hopkins, Altitude 2,606 m (8,550 ft)

    European Space Agency [La Agencia Espacial Europea] [Agence spatiale européenne] [Europäische Weltraumorganisation] (EU)/National Aeronautics and Space Administration SOHO satellite. Launched in 1995.

    National Aeronautics Space Agency NASA Kepler Space Telescope

    CfA-led discoveries throughout this period include canonical work on Supernova 1987A, the “CfA2 Great Wall” (then the largest known coherent structure in the Universe), the best-yet evidence for supermassive black holes, and the first convincing evidence for an extrasolar planet.

    The 1990s also saw the CfA unwittingly play a major role in the history of computer science and the internet: in 1990, SAO developed SAOImage, one of the world’s first X11-based applications made publicly available (its successor, DS9, remains the most widely used astronomical FITS image viewer worldwide). During this time, scientists at the CfA also began work on what would become the Astrophysics Data System (ADS), one of the world’s first online databases of research papers. By 1993, the ADS was running the first routine transatlantic queries between databases, a foundational aspect of the internet today.

    The CfA Today

    Research at the CfA

    Charles Alcock, known for a number of major works related to massive compact halo objects, was named the third director of the CfA in 2004. Today Alcock overseas one of the largest and most productive astronomical institutes in the world, with more than 850 staff and an annual budget in excess of $100M. The Harvard Department of Astronomy, housed within the CfA, maintains a continual complement of approximately 60 Ph.D. students, more than 100 postdoctoral researchers, and roughly 25 undergraduate majors in astronomy and astrophysics from Harvard College. SAO, meanwhile, hosts a long-running and highly rated REU Summer Intern program as well as many visiting graduate students. The CfA estimates that roughly 10% of the professional astrophysics community in the United States spent at least a portion of their career or education there.

    The CfA is either a lead or major partner in the operations of the Fred Lawrence Whipple Observatory, the Submillimeter Array, MMT Observatory, the South Pole Telescope, VERITAS, and a number of other smaller ground-based telescopes. The CfA’s 2019-2024 Strategic Plan includes the construction of the Giant Magellan Telescope as a driving priority for the Center.

    CFA Harvard Smithsonian Submillimeter Array on Mauna Kea, Hawaii, Altitude 4,205 m (13,796 ft).

    South Pole Telescope SPTPOL. The SPT collaboration is made up of over a dozen (mostly North American) institutions, including The University of Chicago ; The University of California-Berkeley ; Case Western Reserve University; Harvard/Smithsonian Astrophysical Observatory; The University of Colorado- Boulder; McGill (CA) University, The University of Illinois, Urbana-Champaign; The University of California- Davis; Ludwig Maximilians Universität München(DE); DOE’s Argonne National Laboratory; and The National Institute for Standards and Technology.

    Along with the Chandra X-ray Observatory, the CfA plays a central role in a number of space-based observing facilities, including the recently launched Parker Solar Probe, Kepler Space Telescope, the Solar Dynamics Observatory (SDO), and HINODE. The CfA, via the Smithsonian Astrophysical Observatory, recently played a major role in the Lynx X-ray Observatory, a NASA-Funded Large Mission Concept Study commissioned as part of the 2020 Decadal Survey on Astronomy and Astrophysics (“Astro2020”). If launched, Lynx would be the most powerful X-ray observatory constructed to date, enabling order-of-magnitude advances in capability over Chandra.

    NASA Parker Solar Probe Plus named to honor Pioneering Physicist Eugene Parker. The Johns Hopkins University Applied Physics Lab.

    National Aeronautics and Space Administration Solar Dynamics Observatory.

    Japan Aerospace Exploration Agency (JAXA) (国立研究開発法人宇宙航空研究開発機構] (JP)/National Aeronautics and Space Administration HINODE spacecraft.

    SAO is one of the 13 stakeholder institutes for the Event Horizon Telescope Board, and the CfA hosts its Array Operations Center. In 2019, the project revealed the first direct image of a black hole.

    Messier 87*, The first image of the event horizon of a black hole. This is the supermassive black hole at the center of the galaxy Messier 87. Image via The Event Horizon Telescope Collaboration released on 10 April 2019 via National Science Foundation.

    The result is widely regarded as a triumph not only of observational radio astronomy, but of its intersection with theoretical astrophysics. Union of the observational and theoretical subfields of astrophysics has been a major focus of the CfA since its founding.

    In 2018, the CfA rebranded, changing its official name to the “Center for Astrophysics | Harvard & Smithsonian” in an effort to reflect its unique status as a joint collaboration between Harvard University and the Smithsonian Institution. Today, the CfA receives roughly 70% of its funding from NASA, 22% from Smithsonian federal funds, and 4% from the National Science Foundation. The remaining 4% comes from contributors including the United States Department of Energy, the Annenberg Foundation, as well as other gifts and endowments.

     
  • richardmitnick 10:45 pm on September 12, 2022 Permalink | Reply
    Tags: "Astronomers discover new brown dwarf with quasi-spherical mass loss", , ALMA, , , , , SSTc2d J163134.1-24006 is most likely a brown dwarf with a mass of about 0.05 solar masses and an elliptical shell of carbon monoxide., , The newfound object designated SSTc2d J163134.1-24006   

    From The National Radio Astronomy Observatory Via “phys.org” : “Astronomers discover new brown dwarf with quasi-spherical mass loss” 

    NRAO Banner

    From The National Radio Astronomy Observatory

    Via

    “phys.org”

    9.12.22

    1
    Herschel column-density map of the Ophiuchus molecular cloud. The magenta star indicates the location of SSTc2d J163134.1. The Lynds L1709 dark cloud in the region is indicated. Credit: Ruiz-Rodriguez et al., 2022.

    Astronomers report the detection of a new brown dwarf as part of the Ophiuchus Disk Survey Employing ALMA [below] (ODISEA) program. The newfound object designated SSTc2d J163134.1-24006, appears to be experiencing a quasi-spherical mass loss. The discovery was detailed in a paper published September 2 for The Astrophysical Journal [below].

    Brown dwarfs are intermediate objects between planets and stars, occupying the mass range between 13 and 80 Jupiter masses (0.012 and 0.076 solar masses). They can burn deuterium but are unable to burn regular hydrogen, which requires a minimum mass of at least 80 Jupiter masses and a core temperature of about 3 million K.

    A team of astronomers led by Dary Ruiz-Rodriguez of the National Radio Astronomy Observatory (NRAO) in Charlottesville, Virginia, have investigated SSTc2d J163134.1-24006, initially identified as a faint stellar object, under the ODISEA project, which is dedicated to study the entire population of protoplanetary disks in the Ophiuchus Molecular Cloud. They found that SSTc2d J163134.1-24006 is most likely a brown dwarf with a mass of about 0.05 solar masses and an elliptical shell of carbon monoxide (CO).

    “SSTc2d J163134.1 was observed as part of the ‘Ophiuchus Disk Survey Employing ALMA’ (ODISEA) program (Project ID: 2016.1.00545.S PI: L. Cieza). ALMA Band 6 (1.3 mm) observations were performed on April 27 and August 22, 2018, during Cycle 5 using the C43-3 configuration (15–500 m baselines),” the researchers wrote in the paper.

    First of all, the team serendipitously discovered an expanding shell of carbon monoxide ejected from an object, with a temperature below 3,000 K, located in the direction of the Ophiuchus Molecular Cloud. Further observations revealed that this shell is associated with SSTc2d J163134.1.

    In order to explain the nature of SSTc2d J163134.1 and its expanding shell, Ruiz-Rodriguez’s team considered various scenarios, including the inside-out collapse of a dense molecular core in the Ophiuchus cloud, the mass loss of a giant star in the distant background, or a shell of gas expelled from a young brown dwarf. According to the researchers, the most plausible one is the brown dwarf hypothesis.

    “We conclude that the source is not a giant star in the distant background (>5–10 kpc) and is most likely to be a young brown dwarf in the Ophiuchus cloud, at a distance of just ∼139 pc,” the astronomers explained.

    Given that emission of carbon monoxide from SSTc2d J163134.1 has an elliptical shape, it was noted that this makes it the first brown dwarf known to exhibit a quasi-spherical mass loss. The authors of the paper assume that a deuterium flash could be responsible for this phenomenon, but more detailed theoretical work is required in order to verify this explanation.

    Science paper:
    The Astrophysical Journal

    See the full article here .


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    Please help promote STEM in your local schools.

    Stem Education Coalition

    The National Radio Astronomy Observatory is a facility of The National Science Foundation, operated under cooperative agreement by The Associated Universities, Inc.


    National Radio Astronomy Observatory Karl G Jansky Very Large Array located in central New Mexico on the Plains of San Agustin, between the towns of Magdalena and Datil, ~50 miles (80 km) west of Socorro. The VLA comprises twenty-eight 25-meter radio telescopes.

    ngVLA, to be located near the location of the NRAO Karl G. Jansky Very Large Array site on the plains of San Agustin, fifty miles west of Socorro, NM, at an elevation of 6970 ft (2124 m) with additional mid-baseline stations currently spread over greater New Mexico, Arizona, Texas, and Mexico.

    National Radio Astronomy Observatory Very Long Baseline Array.

    The European Southern Observatory [La Observatorio Europeo Austral][Observatoire européen austral][Europäische Südsternwarte](EU)(CL))/National Radio Astronomy Observatory/National Astronomical Observatory of Japan(JP) ALMA Array in Chile in the Atacama at Chajnantor plateau, at 5,000 metres.

    Access to ALMA observing time by the North American astronomical community will be through the North American ALMA Science Center (NAASC).

    *The Very Long Baseline Array (VLBA) comprises ten radio telescopes spanning 5,351 miles. It’s the world’s largest, sharpest, dedicated telescope array. With an eye this sharp, you could be in Los Angeles and clearly read a street sign in New York City!

    Astronomers use the continent-sized VLBA to zoom in on objects that shine brightly in radio waves, long-wavelength light that’s well below infrared on the spectrum. They observe blazars, quasars, black holes, and stars in every stage of the stellar life cycle. They plot pulsars, exoplanets, and masers, and track asteroids and planets.

     
  • richardmitnick 10:42 am on August 23, 2022 Permalink | Reply
    Tags: "Case Solved:: Missing Carbon Monoxide was Hiding in the Ice", A huge chunk of carbon monoxide is missing in all observations of disks if astronomers' current predictions of its abundance are correct., A new model has been validated by observations with ALMA., ALMA, , , , Carbon monoxide in planetary nurseries: the compound is ultra-bright and extremely common in protoplanetary disks., Carbon monoxide inaccuracies could have huge implications for the field of astrochemistry., Carbon monoxide is essentially used to trace everything known about disks., Carbon monoxide is three to 100 times less than it should be; it's off by a really huge amount., , , , In planetary disks carbon monoxide is lurking in large chunks of ice solving the decade-old question 'Where is the CO?', Scientists compared CO output to real ALMA observations of carbon monoxide in four well-studied disks — TW Hya; HD 163296; DM Tau and IM Lup., Something hasn't been adding up when it comes to carbon monoxide observations., The four disks weren’t actually missing carbon monoxide at all — it had just morphed into ice which is currently undetectable with a telescope.,   

    From The Harvard-Smithsonian Center for Astrophysics: “Case Solved:: Missing Carbon Monoxide was Hiding in the Ice” 

    From The Harvard-Smithsonian Center for Astrophysics

    8.22.22
    Nadia Whitehead
    Public Affairs Officer
    Center for Astrophysics | Harvard & Smithsonian
    nadia.whitehead@cfa.harvard.edu
    617-721-7371

    In planetary disks carbon monoxide is lurking in large chunks of ice solving the decade-old question ‘Where is the CO?’

    1
    Credit: M.Weiss/Center for Astrophysics | CfA

    Astronomers frequently observe carbon monoxide in planetary nurseries: the compound is ultra-bright and extremely common in protoplanetary disks — regions of dust and gas where planets form around young stars — making it a prime target for scientists.

    But for the last decade or so, something hasn’t been adding up when it comes to carbon monoxide observations, says Diana Powell, a NASA Hubble Fellow at the Center for Astrophysics | Harvard & Smithsonian.

    A huge chunk of carbon monoxide is missing in all observations of disks if astronomers’ current predictions of its abundance are correct.

    Now, a new model — validated by observations with ALMA — has solved the mystery: carbon monoxide has been hiding in ice formations within the disks. The findings are described today in the journal Nature Astronomy [below].

    “This may be one of the biggest unsolved problems in planet-forming disks,” says Powell, who led the study. “Depending on the system observed, carbon monoxide is three to 100 times less than it should be; it’s off by a really huge amount.”

    And carbon monoxide inaccuracies could have huge implications for the field of astrochemistry.

    “Carbon monoxide is essentially used to trace everything we know about disks — like mass, composition and temperature,” Powell explains. “This could mean many of our results for disks have been biased and uncertain because we don’t understand the compound well enough.”

    Intrigued by the mystery, Powell put on her detective hat and leaned on her expertise in the physics behind phase changes — when matter morphs from one state to another, like a gas changing into a solid.

    On a hunch, Powell made alterations to an astrophysical model that’s currently used to study clouds on exoplanets, or planets beyond our solar system.

    “What’s really special about this model is that it has detailed physics for how ice forms on particles,” she explains. “So how ice nucleates onto small particles and then how it condenses. The model carefully tracks where ice is, on what particle it’s located on, how big the particles are, how small they are and then how they move around.”

    Powell applied the adapted model to planetary disks, hoping to generate an in-depth understanding of how carbon monoxide evolves over time in planetary nurseries. To test the model’s validity, Powell then compared its output to real ALMA observations of carbon monoxide in four well-studied disks — TW Hya; HD 163296; DM Tau and IM Lup.

    The results and models worked really well, Powell says.

    The new model lined up with each of the observations, showing that the four disks weren’t actually missing carbon monoxide at all — it had just morphed into ice which is currently undetectable with a telescope.

    Radio observatories like ALMA allow astronomers to view carbon monoxide in space in its gas phase, but ice is much harder to detect with current technology, especially large formations of ice, Powell says.

    The model shows that unlike previous thinking, carbon monoxide is forming on large particles of ice — especially after one million years. Prior to a million years, gaseous carbon monoxide is abundant and detectable in disks.

    “This changes how we thought ice and gas were distributed in disks,” Powell says. “It also shows that detailed modelling like this is important to understand the fundamentals of these environments.”

    Powell hopes her model can be further validated using observations with NASA’s Webb Telescope — which may be powerful enough to finally detect ice in disks, but that remains to be seen.

    Powell, who loves phase changes and the complicated processes behind them, says she is in awe of their influence. “Small-scale ice formation physics influences disk formation and evolution — now that’s really cool.”

    Science paper:
    Nature Astronomy

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings
    Please help promote STEM in your local schools.


    Stem Education Coalition

    The The Harvard-Smithsonian Center for Astrophysics combines the resources and research facilities of the Harvard College Observatory and the Smithsonian Astrophysical Observatory under a single director to pursue studies of those basic physical processes that determine the nature and evolution of the universe. The Smithsonian Astrophysical Observatory is a bureau of the Smithsonian Institution, founded in 1890. The Harvard College Observatory, founded in 1839, is a research institution of the Faculty of Arts and Sciences, Harvard University, and provides facilities and substantial other support for teaching activities of the Department of Astronomy.

    Founded in 1973 and headquartered in Cambridge, Massachusetts, the CfA leads a broad program of research in astronomy, astrophysics, Earth and space sciences, as well as science education. The CfA either leads or participates in the development and operations of more than fifteen ground- and space-based astronomical research observatories across the electromagnetic spectrum, including the forthcoming Giant Magellan Telescope(CL) and the Chandra X-ray Observatory, one of NASA’s Great Observatories.

    GMT Giant Magellan Telescope(CL) 21 meters, to be at the Carnegie Institution for Science’s NSF NOIRLab NOAO Las Campanas Observatory(CL) some 115 km (71 mi) north-northeast of La Serena, Chile, over 2,500 m (8,200 ft) high.

    National Aeronautics and Space Administration Chandra X-ray telescope.

    Hosting more than 850 scientists, engineers, and support staff, the CfA is among the largest astronomical research institutes in the world. Its projects have included Nobel Prize-winning advances in cosmology and high energy astrophysics, the discovery of many exoplanets, and the first image of a black hole. The CfA also serves a major role in the global astrophysics research community: the CfA’s Astrophysics Data System, for example, has been universally adopted as the world’s online database of astronomy and physics papers. Known for most of its history as the “Harvard-Smithsonian Center for Astrophysics”, the CfA rebranded in 2018 to its current name in an effort to reflect its unique status as a joint collaboration between Harvard University and the Smithsonian Institution. The CfA’s current Director (since 2004) is Charles R. Alcock, who succeeds Irwin I. Shapiro (Director from 1982 to 2004) and George B. Field (Director from 1973 to 1982).

    The Center for Astrophysics | Harvard & Smithsonian is not formally an independent legal organization, but rather an institutional entity operated under a Memorandum of Understanding between Harvard University and the Smithsonian Institution. This collaboration was formalized on July 1, 1973, with the goal of coordinating the related research activities of the Harvard College Observatory (HCO) and the Smithsonian Astrophysical Observatory (SAO) under the leadership of a single Director, and housed within the same complex of buildings on the Harvard campus in Cambridge, Massachusetts. The CfA’s history is therefore also that of the two fully independent organizations that comprise it. With a combined lifetime of more than 300 years, HCO and SAO have been host to major milestones in astronomical history that predate the CfA’s founding.

    History of the Smithsonian Astrophysical Observatory (SAO)

    Samuel Pierpont Langley, the third Secretary of the Smithsonian, founded the Smithsonian Astrophysical Observatory on the south yard of the Smithsonian Castle (on the U.S. National Mall) on March 1,1890. The Astrophysical Observatory’s initial, primary purpose was to “record the amount and character of the Sun’s heat”. Charles Greeley Abbot was named SAO’s first director, and the observatory operated solar telescopes to take daily measurements of the Sun’s intensity in different regions of the optical electromagnetic spectrum. In doing so, the observatory enabled Abbot to make critical refinements to the Solar constant, as well as to serendipitously discover Solar variability. It is likely that SAO’s early history as a solar observatory was part of the inspiration behind the Smithsonian’s “sunburst” logo, designed in 1965 by Crimilda Pontes.

    In 1955, the scientific headquarters of SAO moved from Washington, D.C. to Cambridge, Massachusetts to affiliate with the Harvard College Observatory (HCO). Fred Lawrence Whipple, then the chairman of the Harvard Astronomy Department, was named the new director of SAO. The collaborative relationship between SAO and HCO therefore predates the official creation of the CfA by 18 years. SAO’s move to Harvard’s campus also resulted in a rapid expansion of its research program. Following the launch of Sputnik (the world’s first human-made satellite) in 1957, SAO accepted a national challenge to create a worldwide satellite-tracking network, collaborating with the United States Air Force on Project Space Track.

    With the creation of National Aeronautics and Space Administration the following year and throughout the space race, SAO led major efforts in the development of orbiting observatories and large ground-based telescopes, laboratory and theoretical astrophysics, as well as the application of computers to astrophysical problems.

    History of Harvard College Observatory (HCO)

    Partly in response to renewed public interest in astronomy following the 1835 return of Halley’s Comet, the Harvard College Observatory was founded in 1839, when the Harvard Corporation appointed William Cranch Bond as an “Astronomical Observer to the University”. For its first four years of operation, the observatory was situated at the Dana-Palmer House (where Bond also resided) near Harvard Yard, and consisted of little more than three small telescopes and an astronomical clock. In his 1840 book recounting the history of the college, then Harvard President Josiah Quincy III noted that “…there is wanted a reflecting telescope equatorially mounted…”. This telescope, the 15-inch “Great Refractor”, opened seven years later (in 1847) at the top of Observatory Hill in Cambridge (where it still exists today, housed in the oldest of the CfA’s complex of buildings). The telescope was the largest in the United States from 1847 until 1867. William Bond and pioneer photographer John Adams Whipple used the Great Refractor to produce the first clear Daguerrotypes of the Moon (winning them an award at the 1851 Great Exhibition in London). Bond and his son, George Phillips Bond (the second Director of HCO), used it to discover Saturn’s 8th moon, Hyperion (which was also independently discovered by William Lassell).

    Under the directorship of Edward Charles Pickering from 1877 to 1919, the observatory became the world’s major producer of stellar spectra and magnitudes, established an observing station in Peru, and applied mass-production methods to the analysis of data. It was during this time that HCO became host to a series of major discoveries in astronomical history, powered by the Observatory’s so-called “Computers” (women hired by Pickering as skilled workers to process astronomical data). These “Computers” included Williamina Fleming; Annie Jump Cannon; Henrietta Swan Leavitt; Florence Cushman; and Antonia Maury, all widely recognized today as major figures in scientific history. Henrietta Swan Leavitt, for example, discovered the so-called period-luminosity relation for Classical Cepheid variable stars, establishing the first major “standard candle” with which to measure the distance to galaxies. Now called “Leavitt’s Law”, the discovery is regarded as one of the most foundational and important in the history of astronomy; astronomers like Edwin Hubble, for example, would later use Leavitt’s Law to establish that the Universe is expanding, the primary piece of evidence for the Big Bang model.

    Upon Pickering’s retirement in 1921, the Directorship of HCO fell to Harlow Shapley (a major participant in the so-called “Great Debate” of 1920). This era of the observatory was made famous by the work of Cecelia Payne-Gaposchkin, who became the first woman to earn a Ph.D. in astronomy from Radcliffe College (a short walk from the Observatory). Payne-Gapochkin’s 1925 thesis proposed that stars were composed primarily of hydrogen and helium, an idea thought ridiculous at the time. Between Shapley’s tenure and the formation of the CfA, the observatory was directed by Donald H. Menzel and then Leo Goldberg, both of whom maintained widely recognized programs in solar and stellar astrophysics. Menzel played a major role in encouraging the Smithsonian Astrophysical Observatory to move to Cambridge and collaborate more closely with HCO.

    Joint history as the Center for Astrophysics (CfA)

    The collaborative foundation for what would ultimately give rise to the Center for Astrophysics began with SAO’s move to Cambridge in 1955. Fred Whipple, who was already chair of the Harvard Astronomy Department (housed within HCO since 1931), was named SAO’s new director at the start of this new era; an early test of the model for a unified Directorship across HCO and SAO. The following 18 years would see the two independent entities merge ever closer together, operating effectively (but informally) as one large research center.

    This joint relationship was formalized as the new Harvard–Smithsonian Center for Astrophysics on July 1, 1973. George B. Field, then affiliated with University of California- Berkeley, was appointed as its first Director. That same year, a new astronomical journal, the CfA Preprint Series was created, and a CfA/SAO instrument flying aboard Skylab discovered coronal holes on the Sun. The founding of the CfA also coincided with the birth of X-ray astronomy as a new, major field that was largely dominated by CfA scientists in its early years. Riccardo Giacconi, regarded as the “father of X-ray astronomy”, founded the High Energy Astrophysics Division within the new CfA by moving most of his research group (then at American Sciences and Engineering) to SAO in 1973. That group would later go on to launch the Einstein Observatory (the first imaging X-ray telescope) in 1976, and ultimately lead the proposals and development of what would become the Chandra X-ray Observatory. Chandra, the second of NASA’s Great Observatories and still the most powerful X-ray telescope in history, continues operations today as part of the CfA’s Chandra X-ray Center. Giacconi would later win the 2002 Nobel Prize in Physics for his foundational work in X-ray astronomy.

    Shortly after the launch of the Einstein Observatory, the CfA’s Steven Weinberg won the 1979 Nobel Prize in Physics for his work on electroweak unification. The following decade saw the start of the landmark CfA Redshift Survey (the first attempt to map the large scale structure of the Universe), as well as the release of the Field Report, a highly influential Astronomy & Astrophysics Decadal Survey chaired by the outgoing CfA Director George Field. He would be replaced in 1982 by Irwin Shapiro, who during his tenure as Director (1982 to 2004) oversaw the expansion of the CfA’s observing facilities around the world.

    Harvard Smithsonian Center for Astrophysics Fred Lawrence Whipple Observatory located near Amado, Arizona on the slopes of Mount Hopkins, Altitude 2,606 m (8,550 ft)

    European Space Agency [La Agencia Espacial Europea] [Agence spatiale européenne] [Europäische Weltraumorganisation] (EU)/National Aeronautics and Space Administration SOHO satellite. Launched in 1995.

    National Aeronautics Space Agency NASA Kepler Space Telescope

    CfA-led discoveries throughout this period include canonical work on Supernova 1987A, the “CfA2 Great Wall” (then the largest known coherent structure in the Universe), the best-yet evidence for supermassive black holes, and the first convincing evidence for an extrasolar planet.

    The 1990s also saw the CfA unwittingly play a major role in the history of computer science and the internet: in 1990, SAO developed SAOImage, one of the world’s first X11-based applications made publicly available (its successor, DS9, remains the most widely used astronomical FITS image viewer worldwide). During this time, scientists at the CfA also began work on what would become the Astrophysics Data System (ADS), one of the world’s first online databases of research papers. By 1993, the ADS was running the first routine transatlantic queries between databases, a foundational aspect of the internet today.

    The CfA Today

    Research at the CfA

    Charles Alcock, known for a number of major works related to massive compact halo objects, was named the third director of the CfA in 2004. Today Alcock overseas one of the largest and most productive astronomical institutes in the world, with more than 850 staff and an annual budget in excess of $100M. The Harvard Department of Astronomy, housed within the CfA, maintains a continual complement of approximately 60 Ph.D. students, more than 100 postdoctoral researchers, and roughly 25 undergraduate majors in astronomy and astrophysics from Harvard College. SAO, meanwhile, hosts a long-running and highly rated REU Summer Intern program as well as many visiting graduate students. The CfA estimates that roughly 10% of the professional astrophysics community in the United States spent at least a portion of their career or education there.

    The CfA is either a lead or major partner in the operations of the Fred Lawrence Whipple Observatory, the Submillimeter Array, MMT Observatory, the South Pole Telescope, VERITAS, and a number of other smaller ground-based telescopes. The CfA’s 2019-2024 Strategic Plan includes the construction of the Giant Magellan Telescope as a driving priority for the Center.

    CFA Harvard Smithsonian Submillimeter Array on Mauna Kea, Hawaii, Altitude 4,205 m (13,796 ft).

    South Pole Telescope SPTPOL. The SPT collaboration is made up of over a dozen (mostly North American) institutions, including The University of Chicago ; The University of California-Berkeley ; Case Western Reserve University; Harvard/Smithsonian Astrophysical Observatory; The University of Colorado- Boulder; McGill (CA) University, The University of Illinois, Urbana-Champaign; The University of California- Davis; Ludwig Maximilians Universität München(DE); DOE’s Argonne National Laboratory; and The National Institute for Standards and Technology.

    Along with the Chandra X-ray Observatory, the CfA plays a central role in a number of space-based observing facilities, including the recently launched Parker Solar Probe, Kepler Space Telescope, the Solar Dynamics Observatory (SDO), and HINODE. The CfA, via the Smithsonian Astrophysical Observatory, recently played a major role in the Lynx X-ray Observatory, a NASA-Funded Large Mission Concept Study commissioned as part of the 2020 Decadal Survey on Astronomy and Astrophysics (“Astro2020”). If launched, Lynx would be the most powerful X-ray observatory constructed to date, enabling order-of-magnitude advances in capability over Chandra.

    NASA Parker Solar Probe Plus named to honor Pioneering Physicist Eugene Parker. The Johns Hopkins University Applied Physics Lab.

    National Aeronautics and Space Administration Solar Dynamics Observatory.

    Japan Aerospace Exploration Agency (JAXA) (国立研究開発法人宇宙航空研究開発機構] (JP)/National Aeronautics and Space Administration HINODE spacecraft.

    SAO is one of the 13 stakeholder institutes for the Event Horizon Telescope Board, and the CfA hosts its Array Operations Center. In 2019, the project revealed the first direct image of a black hole.

    Messier 87*, The first image of the event horizon of a black hole. This is the supermassive black hole at the center of the galaxy Messier 87. Image via The Event Horizon Telescope Collaboration released on 10 April 2019 via National Science Foundation.

    The result is widely regarded as a triumph not only of observational radio astronomy, but of its intersection with theoretical astrophysics. Union of the observational and theoretical subfields of astrophysics has been a major focus of the CfA since its founding.

    In 2018, the CfA rebranded, changing its official name to the “Center for Astrophysics | Harvard & Smithsonian” in an effort to reflect its unique status as a joint collaboration between Harvard University and the Smithsonian Institution. Today, the CfA receives roughly 70% of its funding from NASA, 22% from Smithsonian federal funds, and 4% from the National Science Foundation. The remaining 4% comes from contributors including the United States Department of Energy, the Annenberg Foundation, as well as other gifts and endowments.

     
  • richardmitnick 8:39 am on August 9, 2022 Permalink | Reply
    Tags: "Discovery of new exoplanet raises questions about planet formation", ALMA, AS 209 is one of several young star systems being studied by the ALMA telescope for clues to planet formation., , , , , , , ,   

    From The University of Florida: “Discovery of new exoplanet raises questions about planet formation” 

    From The University of Florida

    1
    AS 209 is one of several young star systems being studied by the ALMA telescope for clues to planet formation. (ALMA/DSHARP)

    Astronomers have identified one of the youngest exoplanets ever discovered, hidden in the swirl of gas around a newly born star 390 light-years from Earth.

    The Jupiter-sized world offers two key opportunities to scientists studying how all planets, including those in our own solar system, develop. A mere 1.5-million-year-old infant compared to its probable lifespan of billions of years, the planet is so young it can still provide clues about its birth. And this study marks the first time astronomers have analyzed an exoplanet’s surrounding disk of gas, which not only provides more information about the planet’s past but also how its future moons will develop.

    “The best way to study planet formation is to observe planets while they’re forming,” said Jaehan Bae, the University of Florida professor of astronomy who led the new discovery.

    Bae and his international team of collaborators, including UF doctoral student Maria Galloway-Sprietsma, published their findings July 27 in The Astrophysical Journal Letters [below].

    Clues to our past

    “I was always curious to learn how our solar system planets had formed in the past,” Bae said. “We can study planets in our solar system directly in many ways. We can get samples of planets, asteroids and comets. But we still can’t see what happened in the past.”

    The next best thing to seeing into our own solar system’s history is for scientists like Bae to study the birth of exoplanets, those worlds that orbit stars other than our own sun. So Bae’s team turned to ALMA, a clever array of dozens of radio antennas in the Atacama Desert of northern Chile that is powerful enough to spot these far flung planets.

    By combining signals from antennas spread across miles of desert, ALMA acts as a single, enormous telescope.

    The research group focused on a young star system known as AS 209, one of five stars being studied as a part of a broader ALMA program, known as MAPS, designed to expand out understanding of the chemistry of planet formation.

    Scientists can look for clues in each star’s circumstellar disk, the flattened circle of material leftover after the star coalesces in the center of the system. Our solar system once hosted such a disk, and it eventually coalesced into the eight planets.

    The AS 209 circumstellar disk has several distinct rings, akin to the rings surrounding Saturn. After analyzing gaps in these rings and other anomalies in the AS 209 disk, the researchers identified the young planet, surrounded by a cloud of material known as a circumplanetary disk.

    Because the new study is the first to measure the gas of this surrounding material, it provides a much more complete picture of planet formation than previous studies could accomplish.

    “Most of the circumplanetary disk mass is in the gas, not the solid particles. If you see only solid particles in the system, then you’re studying a minor component of the disk,” Bae said. “And in fact one thing we found is the gas-to-dust mass ratio is much, much larger than previously expected, at least 1000-to-1.”

    New mysteries

    While the planet’s young age and surrounding gas will help astronomers answer existing questions about planet formation, the planet offers up new mysteries of its own.

    Namely: How did it form so far away from its own star?

    Bae’s team pinpointed the exoplanet at a whopping 200 astronomical units from the AS 209 star. One astronomical unit is the distance between the Earth and the sun. Neptune, the most distant planet, sits at 30 astronomical units, while Pluto orbits roughly 40 astronomical units out from the sun. Beyond that, as far as scientists know, lies nothing but a cloud of small asteroids, comets, and dwarf planets.

    Bae’s team has proposed two main models for how the planet formed at this immense distance. In one, the young star’s own gravity jostled the leftover disk of material enough to seed a new planet. The other model relies on the planet seeding itself through the slow accumulation of tiny particles of solid material until there’s enough mass to form a large core.

    But neither model sits neatly with the data. The circumstellar disk of the young star seems too small for its gravity to have initiated planet formation at this distance. At the same time, astronomers saw little evidence of the kind of tiny, grain-of-sand-sized particles that clump together to eventually form a planet’s core at the distance of the new exoplanet.

    Fortunately, the researchers may not have to wait much longer to get a clearer picture of the planet’s unusual genesis. They have been approved for an early analysis with the new James Webb Space Telescope. The telescope will observe the AS 209 system this month, which will provide key information that could untangle the mystery.

    “That’s what makes this system really exciting,” said Bae. “We can follow it with future observations.”

    Science paper:
    The Astrophysical Journal Letters

    See the full article here.

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    Please help promote STEM in your local schools.

    Stem Education Coalition

    The University of Florida is a public land-grant research university in Gainesville, Florida. It is a senior member of the State University System of Florida, traces its origins to 1853, and has operated continuously on its Gainesville campus since September 1906.

    After the Florida state legislature’s creation of performance standards in 2013, the Florida Board of Governors designated the University of Florida as one of the three “preeminent universities” among the twelve universities of the State University System of Florida. For 2022, U.S. News & World Report ranked Florida as the 5th (tied) best public university and 28th (tied) best university in the United States. The University of Florida is the only member of the Association of American Universities in Florida and is classified among “R1: Doctoral Universities – Very high research activity”.

    The university is accredited by the Southern Association of Colleges and Schools (SACS). It is the third largest Florida university by student population, and is the fifth largest single-campus university in the United States with 57,841 students enrolled for during the 2020–21 school year. The University of Florida is home to 16 academic colleges and more than 150 research centers and institutes. It offers multiple graduate professional programs—including business administration, engineering, law, dentistry, medicine, pharmacy and veterinary medicine—on one contiguous campus, and administers 123 master’s degree programs and 76 doctoral degree programs in eighty-seven schools and departments. The university’s seal is also the seal of the state of Florida, which is on the state flag, though in blue rather than multiple colors.

    The University of Florida’s intercollegiate sports teams, commonly known as the “Florida Gators”, compete in National Collegiate Athletic Association (NCAA) Division I and the Southeastern Conference (SEC). In their 111-year history, the university’s varsity sports teams have won 42 national team championships, 37 of which are NCAA titles, and Florida athletes have won 275 individual national championships. In addition, as of 2021, University of Florida students and alumni have won 143 Olympic medals, including 69 gold medals.

    The University of Florida traces its origins to 1853, when the East Florida Seminary, the oldest of the University of Florida’s four predecessor institutions, was founded in Ocala, Florida.

    On January 6, 1853, Governor Thomas Brown signed a bill that provided public support for higher education in Florida. Gilbert Kingsbury was the first person to take advantage of the legislation, and established the East Florida Seminary, which operated until the outbreak of the Civil War in 1861. The East Florida Seminary was Florida’s first state-supported institution of higher learning.

    James Henry Roper, an educator from North Carolina and a state senator from Alachua County, had opened a school in Gainesville, the Gainesville Academy, in 1858. In 1866, Roper offered his land and school to the State of Florida in exchange for the East Florida Seminary’s relocation to Gainesville.

    The second major precursor to the University of Florida was the Florida Agricultural College, established at Lake City by Jordan Probst in 1884. Florida Agricultural College became the state’s first land-grant college under the Morrill Act. In 1903, the Florida Legislature, looking to expand the school’s outlook and curriculum beyond its agricultural and engineering origins, changed the name of Florida Agricultural College to the “University of Florida,” a name the school would hold for only two years.

    In 1905, the Florida Legislature passed the Buckman Act, which consolidated the state’s publicly supported higher education institutions. The member of the legislature who wrote the act, Henry Holland Buckman, later became the namesake of Buckman Hall, one of the first buildings constructed on the new university’s campus. The Buckman Act organized the State University System of Florida and created the Florida Board of Control to govern the system. It also abolished the six pre-existing state-supported institutions of higher education, and consolidated the assets and academic programs of four of them to form the new “University of the State of Florida.” The four predecessor institutions consolidated to form the new university included the University of Florida at Lake City (formerly Florida Agricultural College) in Lake City, the East Florida Seminary in Gainesville, the St. Petersburg Normal and Industrial School in St. Petersburg, and the South Florida Military College in Bartow.

    The Buckman Act also consolidated the colleges and schools into three institutions segregated by race and gender—the University of the State of Florida for white men, the Florida Female College for white women, and the State Normal School for Colored Students for African-American men and women.

    The City of Gainesville, led by its mayor William Reuben Thomas, campaigned to be home to the new university. On July 6, 1905, the Board of Control selected Gainesville for the new university campus. Andrew Sledd, president of the pre-existing University of Florida at Lake City, was selected to be the first president of the new University of the State of Florida. The 1905–1906 academic year was a year of transition; the new University of the State of Florida was legally created, but operated on the campus of the old University of Florida in Lake City until the first buildings on the new campus in Gainesville were complete. Architect William A. Edwards designed the first official campus buildings in the Collegiate Gothic style. Classes began on the new Gainesville campus on September 26, 1906, with 102 students enrolled.

    In 1909, the school’s name was simplified from the “University of the State of Florida” to the “University of Florida.”

    The alligator was incidentally chosen as the school mascot in 1911, after a local vendor ordered and sold school pennants imprinted with an alligator emblem since the animal is very common in freshwater habitats in the Gainesville area and throughout the state. The mascot was a popular choice, and the university’s sports teams quickly adopted the nickname.

    The school colors of orange and blue were also officially established in 1911, though the reasons for the choice are unclear. The most likely rationale was that they are a combination of the colors of the university’s two largest predecessor institutions, as the East Florida Seminary used orange and black while Florida Agricultural College used blue and white. The older school’s colors may have been an homage to early Scottish and Ulster-Scots Presbyterian settlers of north central Florida, whose ancestors were originally from Northern Ireland and the Scottish Lowlands.

    In 1909, Albert Murphree was appointed the university’s second president. He organized the university into several colleges, increased enrollment from under 200 to over 2,000, and was instrumental in the founding of the Florida Blue Key leadership society. Murphree is the only University of Florida president honored with a statue on campus.

    In 1924, the Florida Legislature mandated women of a “mature age” (at least twenty-one years old) who had completed sixty semester hours from a “reputable educational institution” be allowed to enroll during regular semesters at the University of Florida in programs that were unavailable at Florida State College for Women. Before this, only the summer semester was coeducational, to accommodate women teachers who wanted to further their education during the summer break. Lassie Goodbread-Black from Lake City became the first woman to enroll at the University of Florida, in the College of Agriculture in 1925.

    John J. Tigert became the third university president in 1928. Disgusted by the under-the-table payments being made by universities to athletes, Tigert established the grant-in-aid athletic scholarship program in the early 1930s, which was the genesis of the modern athletic scholarship plan used by the National Collegiate Athletic Association. Inventor and educator Blake R Van Leer was hired as Dean to launch new engineering departments and scholarships. Van Leer also managed all applications for federal funding, chaired the Advanced Planning Committee per Tigert’s request. These efforts included consulting for the Florida Emergency Relief Administration throughout the 1930s.

    Beginning in 1946, there was dramatically increased interest among male applicants who wanted to attend the University of Florida, mostly returning World War II veterans who could attend college under the GI Bill of Rights (Servicemen’s Readjustment Act). Unable to immediately accommodate this increased demand, the Florida Board of Control opened the Tallahassee Branch of the University of Florida on the campus of Florida State College for Women in Tallahassee. By the end of the 1946–47 school year, 954 men were enrolled at the Tallahassee Branch. The following semester, the Florida Legislature returned the Florida State College for Women to coeducational status and renamed it Florida State University. These events also opened up all of the colleges that comprise the University of Florida to female students. Florida Women’s Hall of Fame member Marylyn Van Leer became the first woman to receive a master’s degree in engineering. African-American students were allowed to enroll starting in 1958. Shands Hospital opened in 1958 along with the University of Florida College of Medicine to join the established College of Pharmacy. Rapid campus expansion began in the 1950s and continues today.

    The University of Florida is one of three Florida public universities, along with Florida State University and the University of South Florida, to be designated as a “preeminent university” by Florida senate bill 1076, enacted by the Florida legislature and signed into law by the governor in 2013. As a result, the preeminent universities receive additional funding to improve the academics and national reputation of higher education within the state of Florida.

    In 1985, the University of Florida was invited to join The Association of American Universities, an organization of sixty-two academically prominent public and private research universities in the United States and Canada. Florida is one of the seventeen public, land-grant universities that belong to the AAU. In 2009, President Bernie Machen and the University of Florida Board of Trustees announced a major policy transition for the university. The Board of Trustees supported the reduction in the number of undergraduates and the shift of financial and other academic resources to graduate education and research. In 2017, the University of Florida became the first university in the state of Florida to crack the top ten best public universities according to U.S. News. The University of Florida was awarded $900.7 million in annual research expenditures in sponsored research for the 2020 fiscal year. In 2017, university president Kent Fuchs announced a plan to hire 500 new faculty to break into the top five best public universities; the newest faculty members would be hired in STEM fields.

    In its 2021 edition, U.S. News & World Report ranked the University of Florida as tied for the fifth-best public university in the United States, and tied for 28th overall among all national universities, public and private.

    Many of the University of Florida’s graduate schools have received top-50 national rankings from U.S. News & World Report with the school of education 25th, Florida’s Hough School of Business 25th, Florida’s Medical School (research) tied for 43rd, the Engineering School tied for 45th, the Levin College of Law tied for 31st, and the Nursing School tied for 24th in the 2020 rankings.

    Florida’s graduate programs ranked for 2020 by U.S. News & World Report in the nation’s top 50 were audiology tied for 26th, analytical chemistry 11th, clinical psychology tied for 31st, computer science tied for 49th, criminology 19th, health care management tied for 33rd, nursing-midwifery tied for 35th, occupational therapy tied for 17th, pharmacy tied for 9th, physical therapy tied for 10th, physician assistant tied for 21st, physics tied for 37th, psychology tied for 39th, public health tied for 37th, speech-language pathology tied for 28th, statistics tied for 40th, and veterinary medicine 9th.

    In 2013, U.S. News & World Report ranked the engineering school 38th nationally, with its programs in biological engineering ranked 3rd, materials engineering 11th, industrial engineering 13th, aerospace engineering 26th, chemical engineering 28th, environmental engineering 30th, computer engineering 31st, civil engineering 32nd, electrical engineering 34th, mechanical engineering 44th.

    The 2018 Academic Ranking of World Universities list assessed the University of Florida as 86th among global universities, based on overall research output and faculty awards. In 2017, Washington Monthly ranked the University of Florida 18th among national universities, with criteria based on research, community service, and social mobility. The lowest national ranking received by the university from a major publication comes from Forbes which ranked the university 68th in the nation in 2018. This ranking focuses mainly on net positive financial impact, in contrast to other rankings, and generally ranks liberal arts colleges above most research universities.

    University of Florida received the following rankings by The Princeton Review in its latest Best 380 Colleges Rankings: 13th for Best Value Colleges without Aid, 18th for Lots of Beer, and 42nd for Best Value Colleges. It also was named the number one vegan-friendly school for 2014, according to a survey conducted by PETA.

    On Forbes’ 2016 list of Best Value Public Colleges, University of Florida was ranked second. It was also ranked third on Forbes’ Overall Best Value Colleges Nationwide.

    The university spent over $900 million on research and development in 2020, ranking it one of the highest in the nation. According to a 2019 study by the university’s Institute of Food and Agricultural Sciences, the university contributed $16.9 billion to Florida’s economy and was responsible for over 130,000 jobs in the 2017–18 fiscal year. The Milken Institute named University of Florida one of the top-five U.S. institutions in the transfer of biotechnology research to the marketplace (2006). Some 50 biotechnology companies have resulted from faculty research programs. Florida consistently ranks among the top 10 universities in licensing. Royalty and licensing income includes the glaucoma drug Trusopt, the sports drink Gatorade, and the Sentricon termite elimination system. The Institute of Food and Agricultural Sciences is ranked No. 1 by The National Science Foundation in Research and Development. University of Florida ranked seventh among all private and public universities for the number of patents awarded for 2005.

    Research includes diverse areas such as health-care and citrus production (the world’s largest citrus research center). In 2002, Florida began leading six other universities under a $15 million National Aeronautics and Space Administration grant to work on space-related research during a five-year period. The university’s partnership with Spain helped to create the world’s largest single-aperture optical telescope in the Canary Islands (the cost was $93 million).

    Plans are also under way for the University of Florida to construct a 50,000-square-foot (4,600 m2) research facility in collaboration with the Burnham Institute for Medical Research that will be in the center of University of Central Florida’s Health Sciences Campus in Orlando, Florida. Research will include diabetes, aging, genetics and cancer.

    The University of Florida has made great strides in the space sciences over the last decade. The Astronomy Department’s focus on the development of image-detection devices has led to increases in funding, telescope time, and significant scholarly achievements. Faculty members in organic chemistry have made notable discoveries in astrobiology, while faculty members in physics have participated actively in the Laser Interferometer Gravitational-Wave Observatory (LIGO) project, the largest and most ambitious project ever funded by the NSF.

    .

    Through the Department of Mechanical and Aerospace Engineering, the University of Florida is the lead institution on the NASA University Research, Engineering, and Technology Institute (URETI) for Future Space Transport project to develop the next-generation space shuttle.

    In addition, the university also performs diabetes research in a statewide screening program that has been sponsored by a $10 million grant from the American Diabetes Association. The University of Florida also houses one of the world’s leading lightning research teams. University scientists have started a biofuels pilot plant designed to test ethanol-producing technology. The university is also host to a nuclear research reactor known for its Neutron Activation Analysis Laboratory. In addition, the University of Florida is the first American university to receive a European Union grant to house a Jean Monnet Centre of Excellence.

    The University of Florida manages or has a stake in numerous notable research centers, facilities, institutes, and projects

    Askew Institute
    Bridge Software Institute
    Cancer and Genetics Research Complex
    Cancer Hospital
    Center for African Studies
    Center for Business Ethics Education and Research
    Center for Latin American Studies
    Center for Public Service
    Emerging Pathogens Institute
    Entrepreneurship and Innovation Center
    International Center
    Floral Genome Project
    Florida Institute for Sustainable Energy
    Florida Lakewatch
    Gran Telescopio Canarias
    Infectious Disease Pharmacokinetics Laboratory
    Lake Nona Medical City
    McKnight Brain Institute
    Moffitt Cancer Center & Research Institute
    National High Magnetic Field Laboratory
    Rosemary Hill Observatory
    UF Innovate-Sid Martin Biotech
    UFHSA
    UF Training Reactor
    Whitney Laboratory for Marine Bioscience

    Student media

    The University of Florida community includes six major student-run media outlets and companion Web sites.

    The Independent Florida Alligator is the largest student-run newspaper in the United States, and operates without oversight from the university administration.
    The Really Independent Florida Crocodile, a parody of the Alligator, is a monthly magazine started by students.
    Tea Literary & Arts Magazine is UF’s student-run undergraduate literary and arts publication, established in 1995.
    WRUF (850 AM and 95.3 FM) includes ESPN programming, local sports news and talk programming produced by the station’s professional staff and the latest local sports news produced by the college’s Innovation News Center.
    WRUF-FM (103.7 FM) broadcasts country music and attracts an audience from the Gainesville and Ocala areas.
    WRUF-LD is a low-power television station that carries weather, news, and sports programming.
    WUFT is a PBS member station with a variety of programming that includes a daily student-produced newscast.
    WUFT-FM (89.1 FM) is an NPR member radio station which airs news and public affairs programming, including student-produced long-form news reporting. WUFT-FM’s programming also airs on WJUF-FM (90.1). In addition, WUFT offers 24-hour classical/arts programming on 92.1.

    Various other journals and magazines are published by the university’s academic units and student groups, including the Bob Graham Center-affiliated Florida Political Review and the literary journal Subtropics.

     
  • richardmitnick 11:36 am on June 26, 2022 Permalink | Reply
    Tags: "Astrometry": The measurement of stars’ movements through space, "Astronomers Radically Reimagine the Making of the Planets", "Minimum-mass solar nebula", ALMA, ALMA disproved the classical model of planetary formation., , , , How did we get here? Is there anywhere else like here?, New data from our own solar system no longer matches classic theories about how planets are made., , Observations of faraway worlds have forced a near-total rewrite of the story of our solar system., Pebble accretion is now a favored theory for how gas giant cores are made., , Starting in 2013 ALMA captured stunning images of neatly sculpted infant star systems., Teams of researchers are working out the rules of dust and pebble assembly and how planets move once they coalesce., The exoplanet hunt took off after the Kepler space telescope opened its lens in 2009., We come from a diffuse cloud of gas and dust.   

    From “WIRED“: “Astronomers Radically Reimagine the Making of the Planets” 

    From “WIRED“

    Jun 26, 2022
    Rebecca Boyle

    Observations of faraway worlds have forced a near-total rewrite of the story of our solar system.

    1
    Newborn star systems imaged by the ALMA telescope, featuring protoplanetary disks with rings, arcs, filaments and spirals, are among the observations changing the theory of how planets are made.Illustration: S. Andrews et al.; N. Lira/ALMA/ESO/NAOJ/NRAO.

    Start at the center, with the sun. Our middle-aged star may be more placid than most, but it is otherwise unremarkable. Its planets, however, are another story.

    First, Mercury: More charred innards than fully fledged planet, it probably lost its outer layers in a traumatic collision long ago. Next come Venus and Earth, twins in some respects, though oddly only one is fertile. Then there’s Mars, another wee world, one that, unlike Mercury, never lost layers; it just stopped growing. Following Mars, we have a wide ring of leftover rocks, and then things shift. Suddenly there is Jupiter, so big it’s practically a half-baked sun, containing the vast majority of the material left over from our star’s creation. Past that are three more enormous worlds—Saturn, Uranus, and Neptune—forged of gas and ice. The four gas giants have almost nothing in common with the four rocky planets, despite forming at roughly the same time, from the same stuff, around the same star. The solar system’s eight planets present a puzzle: Why these?

    Now look out past the sun, way beyond. Most of the stars harbor planets of their own. Astronomers have spotted thousands of these distant star-and-planet systems. But strangely, they have so far found none that remotely resemble ours. So the puzzle has grown harder: Why these, and why those?

    The swelling catalog of extrasolar planets, along with observations of distant, dusty planet nurseries [Astronomy & Astrophysics] and even new data from our own solar system, no longer matches classic theories about how planets are made. Planetary scientists, forced to abandon decades-old models, now realize there may not be a grand unified theory of world-making—no single story that explains every planet around every star, or even the wildly divergent orbs orbiting our sun. “The laws of physics are the same everywhere, but the process of building planets is sufficiently complicated that the system becomes chaotic,” said Alessandro Morbidelli, a leading figure in planetary formation and migration theories and an astronomer at the Côte d’Azur Observatory in Nice, France.

    Still, the findings are animating new research. Amid the chaos of world-building, patterns have emerged, leading astronomers toward powerful new ideas. Teams of researchers are working out the rules of dust and pebble assembly and how planets move once they coalesce. Fierce debate rages over the timing of each step, and over which factors determine a budding planet’s destiny. At the nexus of these debates are some of the oldest questions humans have asked ourselves: How did we get here? Is there anywhere else like here?

    A Star and Its Acolytes Are Born

    Astronomers have understood the basic outlines of the solar system’s origins for nearly 300 years. The German philosopher Immanuel Kant, who like many Enlightenment thinkers dabbled in astronomy, published a theory in 1755 that remains pretty much correct. “All the matter making up the spheres belonging to our solar system, all the planets and comets, at the origin of all things was broken down into its elementary basic material,” he wrote.

    Indeed, we come from a diffuse cloud of gas and dust. Four and a half billion years ago, probably nudged by a passing star or by the shock wave of a supernova, the cloud collapsed under its own gravity to form a new star. It’s how things went down afterward that we don’t really understand.

    Once the sun ignited, surplus gas swirled around it. Eventually, the planets formed there. The classical model that explained this, known as the minimum-mass solar nebula, envisioned a basic “protoplanetary disk” filled with just enough hydrogen, helium, and heavier elements to make the observed planets and asteroid belts. The model, which dates to 1977, assumed planets formed where we see them today, beginning as small “planetesimals,” then incorporating all the material in their area like locusts consuming every leaf in a field.

    “The model was just somehow making this assumption that the solar disk was filled with planetesimals,” said Joanna Drążkowska, an astrophysicist at the Ludwig Maximilian University of Munich and author of a recent review chapter on the field. “People were not considering any smaller objects—no dust, no pebbles.”

    Astronomers vaguely reasoned that planetesimals arose because dust grains pushed around by the gas would have drifted into piles, the way wind sculpts sand dunes. The classical model had planetesimals randomly strewn throughout the solar nebula, with a statistical distribution of sizes following what physicists call a power law, meaning there are more small ones than big ones. “Just a few years ago, everybody was assuming the planetesimals were distributed in a power law throughout the nebula,” said Morbidelli, “but now we know it is not the case.”

    The change came courtesy of a handful of silver parabolas in Chile’s Atacama Desert. The Atacama Large Millimeter/submillimeter Array (ALMA) is designed to detect light from cool, millimeter-size objects, such as dust grains around newborn stars.

    Starting in 2013 ALMA captured stunning images of neatly sculpted infant star systems, with putative planets embedded in the hazy disks around the new stars.

    Astronomers previously imagined these disks as smooth halos that grew more diffuse as they extended outward, away from the star. But ALMA showed disks with deep, dark gaps, like the rings of Saturn; others with arcs and filaments; and some containing spirals, like miniature galaxies. “ALMA changed the field completely,” said David Nesvorny, an astronomer at the Southwest Research Institute in Boulder, Colorado.

    ALMA disproved the classical model of planetary formation. “We have to now reject it and start thinking about completely different models,” Drążkowska said. The observations showed that, rather than being smoothly dispersed through the disk, dust collects in particular places, as dust likes to do, and that is where the earliest planet embryos are made. Some dust, for instance, probably clumps together at the “snow line,” the distance from the star where water freezes. Recently, Morbidelli and Konstantin Batygin, an astronomer at the California Institute of Technology, argued [Nature Astronomy] that dust also clumps at a condensation line where silicates form droplets instead of vapor. These condensation lines probably cause traffic jams, curbing the rate at which dust falls toward the star and allowing it to pile up.

    “It’s a new paradigm,” Morbidelli said.

    From Dust to Planets

    Even before ALMA showed where dust likes to accrue, astronomers were struggling to understand how it could pile up quickly enough to form a planet—especially a giant one. The gas surrounding the infant sun would have dissipated within about 10 million years, which means Jupiter would have had to collect most of it within that time frame. That means dust must have formed Jupiter’s core very soon after the sun ignited. The Juno mission to Jupiter showed that the giant planet probably has a fluffy core, suggesting it formed fast. But how?

    The problem, apparent to astronomers since about the year 2000, is that turbulence, gas pressure, heat, magnetic fields, and other factors would prevent dust from orbiting the sun in neat paths, or from drifting into big piles. Moreover, any big clumps would likely be drawn into the sun by gravity.

    In 2005, Andrew Youdin and Jeremy Goodman, then of Princeton University, published a new theory [The Astrophysical Journal] for dust clumps that went part of the way toward a solution. A few years after the sun ignited, they argued, gas flowing around the star formed headwinds that forced dust to gather in clumps, and kept the clumps from falling into the star. As the primordial dust bunnies grew bigger and denser, eventually they collapsed under their own gravity into compact objects. This idea, called streaming instability, is now a widely accepted model for how millimeter-size dust grains can quickly turn into large rocks. The mechanism can form planetesimals about 100 kilometers across, which then merge with one another in collisions.

    But astronomers still struggled to explain the creation of much bigger worlds like Jupiter.

    In 2012, Anders Johansen and Michiel Lambrechts, both at Lund University in Sweden, proposed a variation [Astronomy & Astrophysics] on planet growth dubbed pebble accretion. According to their idea, planet embryos the size of the dwarf planet Ceres that arise through streaming instability quickly grow much bigger. Gravity and drag in the circumstellar disk would cause dust grains and pebbles to spiral onto these objects, which would grow apace, like a snowball rolling downhill.

    2
    Illustration: Merrill Sherman/Quanta Magazine.

    Pebble accretion is now a favored theory for how gas giant cores are made, and many astronomers argue it may be taking place in those ALMA images, allowing giant planets to form in the first few million years after a star is born. But the theory’s relevance to the small, terrestrial planets near the sun is controversial. Johansen, Lambrechts, and five coauthors published research last year [Science Advances] showing how inward-drifting pebbles could have fed the growth of Venus, Earth, Mars, and Theia—a since-obliterated world that collided with Earth, ultimately creating the moon. But problems remain. Pebble accretion does not say much about giant impacts like the Earth-Theia crash, which were vital processes in shaping the terrestrial planets, said Miki Nakajima, an astronomer at the University of Rochester. “Even though pebble accretion is very efficient and is a great way to avoid issues with the classical model, it doesn’t seem to be the only way” to make planets, she said.

    Morbidelli rejects the idea of pebbles forming rocky worlds, in part because geochemical samples suggest that Earth formed over a long period, and because meteorites come from rocks of widely varying ages. “It’s a matter of location,” he said. “Processes are different depending on the environment. Why not, right? I think that makes qualitative sense.”

    Research papers appear nearly every week about the early stages of planet growth, with astronomers arguing about the precise condensation points in the solar nebula; whether planetesimals start out with rings that fall onto the planets; when the streaming instability kicks in; and when pebble accretion does, and where. People can’t agree on how Earth was built, let alone terrestrial planets around distant stars.

    Planets on the Move

    The five wanderers of the night sky—Mercury, Venus, Mars, Jupiter and Saturn—were the only known worlds besides this one for most of human history. Twenty-six years after Kant published his nebular hypothesis, William Herschel found another, fainter wanderer and named it Uranus. Then Johann Gottfried Galle spotted Neptune in 1846. Then, a century and a half later, the number of known planets suddenly shot up.

    It started in 1995, when Didier Queloz and Michel Mayor of the University of Geneva pointed a telescope at a sunlike star called 51 Pegasi and noticed it wobbling. They inferred that it’s being tugged at by a giant planet closer to it than Mercury is to our sun. Soon, more of these shocking “hot Jupiters” were seen orbiting other stars.

    The exoplanet hunt took off after the Kepler space telescope opened its lens in 2009.

    We now know the cosmos is peppered with planets; nearly every star has at least one, and probably more. Most seem to have planets we lack, however: hot Jupiters, for instance, as well as a class of midsize worlds that are bigger than Earth but smaller than Neptune, uncreatively nicknamed “super-Earths” or “sub-Neptunes.” No star systems have been found that resemble ours, with its four little rocky planets near the sun and four gas giants orbiting far away. “That does seem to be something that is unique to our solar system that is unusual,” said Seth Jacobson, an astronomer at Michigan State University.

    Enter the Nice model, an idea that may be able to unify the radically different planetary architectures. In the 1970s, geochemical analysis of the rocks collected by Apollo astronauts suggested that the moon was battered by asteroids 3.9 billion years ago—a putative event known as the Late Heavy Bombardment. In 2005, inspired by this evidence, Morbidelli and colleagues in Nice argued that Jupiter, Saturn, Uranus, and Neptune did not form in their present locations, as the earliest solar nebula model held, but instead moved around 3.9 billion years ago. In the Nice model (as the theory became known), the giant planets changed their orbits wildly at that time, which sent an asteroid deluge toward the inner planets.

    3
    Illustration: Merrill Sherman/Quanta Magazine.

    The evidence for the Late Heavy Bombardment is no longer considered convincing, but the Nice model has stuck. Morbidelli, Nesvorny, and others now conclude that the giants probably migrated even earlier in their history, and that—in an orbital pattern dubbed the Grand Tack—Saturn’s gravity probably stopped Jupiter from moving all the way in toward the sun, where hot Jupiters are often found.

    In other words, we might have gotten lucky in our solar system, with multiple giant planets keeping each other in check, so that none swung sunward and destroyed the rocky planets.

    “Unless there is something to arrest that process, we would end up with giant planets mostly close to their host stars,” said Jonathan Lunine, an astronomer at Cornell University. “Is inward migration really a necessary outcome of the growth of an isolated giant planet? What are the combinations of multiple giant planets that could arrest that migration? It’s a great problem.”

    There is also, according to Morbidelli, “a fierce debate about the timing” of the giant-planet migration—and a possibility that it actually helped grow the rocky planets rather than threatening to destroy them after they grew. Morbidelli just launched a five-year project to study whether an unstable orbital configuration soon after the sun’s formation might have helped stir up rocky remains, coaxing the terrestrial worlds into being.

    The upshot is that many researchers now think giant planets and their migrations might dramatically affect the fates of their rocky brethren, in this solar system and others. Jupiter-size worlds might help move asteroids around, or they could limit the number of terrestrial worlds that form. This is a leading hypothesis for explaining the small stature of Mars: It would have grown bigger, maybe to Earth size, but Jupiter’s gravitational influence cut off the supply of material. Many stars studied by the Kepler telescope harbor super-Earths in close orbits, and scientists are split on whether those are likelier to be accompanied by giant planets farther out. Teams have convincingly shown both correlations and anti-correlations between the two exoplanet types, said Rachel Fernandes, a graduate student at the University of Arizona; this indicates that there’s not enough data yet to be sure. “That’s one of those things that is really fun at conferences,” she said. “You’re like, ‘Yeah, yell at each other, but which science is better?’ You don’t know.”

    Rebounding Planets

    Recently, Jacobson came up with a new model that radically changes the timing of the Nice model migration. In a paper published in April in Nature, he, Beibei Liu of Zhejiang University in China, and Sean Raymond of the University of Bordeaux in France argued that gas flow dynamics may have caused the giant planets to migrate only a few million years after they formed—100 times earlier than in the original Nice model and probably before Earth itself arose.

    In the new model, the planets “rebounded,” moving in and then back out as the sun warmed up the gas in the disk and blew it off into oblivion. This rebound would have happened because, when a baby giant planet is bathed in a warm disk of gas, it feels an inward pull toward dense gas closer to the star and an outward pull from gas farther out. The inward pull is greater, so the baby planet gradually moves closer to its star. But after the gas begins to evaporate, a few million years after the star’s birth, the balance changes. More gas remains on the far side of the planet relative to the star, so the planet is dragged back out.

    The rebound “is a pretty significant shock to the system. It can destabilize a very nice arrangement,” Jacobson said. “But this does a great job of explaining [features] of the giant planets in terms of their inclination and eccentricity.” It also tracks with evidence that hot Jupiters seen in other star systems are on unstable orbits—perhaps bound for a rebound.

    Between condensation lines, pebbles, migrations, and rebounds, a complex story is taking shape. Still, for now, some answers may be in hiding. Most of the planet-finding observatories use search methods that turn up planets that orbit close to their host stars. Lunine said he would like to see planet hunters use astrometry, or the measurement of stars’ movements through space, which could reveal distantly orbiting worlds. But he and others are most excited for the Nancy Grace Roman Space Telescope, set to launch in 2027.

    Roman will use microlensing, measuring how the light from a background star is warped by the gravity of a foreground star and its planets.

    That will let the telescope capture planets with orbital distances between Earth’s and Saturn’s—a “sweet spot,” Lunine said.

    Nesvorny said modelers will continue tinkering with code and trying to understand the finer points of particle distributions, ice lines, condensation points, and other chemistry that may play a role in where planetesimals coalesce. “It will take the next few decades to understand that in detail,” he said.

    Time is the essence of the problem. Human curiosity may be unbounded, but our lives are short, and the birth of planets lasts eons. Instead of watching the process unfold, we have only snapshots from different points.

    Batygin, the Caltech astronomer, compared the painstaking effort to reverse-engineer planets to trying to model an animal, even a simple one. “An ant is way more complicated than a star,” Batygin said. “You can perfectly well imagine writing a code that captures a star in pretty good detail,” whereas “you could never model the physics and chemistry of an ant and hope to capture the whole thing. In planet formation, we are somewhere between an ant and a star.”

    See the full article here .

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    Please help promote STEM in your local schools.

    Stem Education Coalition

     
  • richardmitnick 10:14 am on June 16, 2022 Permalink | Reply
    Tags: "New maps of asteroid Psyche reveal an ancient world of metal and rock", ALMA, , , , , ,   

    From The Massachusetts Institute of Technology: “New maps of asteroid Psyche reveal an ancient world of metal and rock” 

    From The Massachusetts Institute of Technology

    June 15, 2022
    Jennifer Chu

    The varied surface suggests a dynamic history, which could include metallic eruptions, asteroid-shaking impacts, and a lost rocky mantle.


    Maps of the asteroid Psyche
    On the left, this map shows surface properties on Psyche, from sandy areas (purple/low) to rocky areas (yellow/high). The map on the right shows metal abundances on Psyche, from low (purple) to high (yellow).

    1
    Astronomers at MIT and elsewhere have mapped the composition of asteroid Psyche, revealing a surface of metal, sand, and rock. Credit: Screenshot courtesy of NASA.

    Later this year, NASA is set to launch a probe the size of a tennis court to the asteroid belt, a region between the orbits of Mars and Jupiter where remnants of the early solar system circle the sun. Once inside the asteroid belt, the spacecraft will zero in on Psyche, a large, metal-rich asteroid that is thought to be the ancient core of an early planet. The probe, named after its asteroid target, will then spend close to two years orbiting and analyzing Psyche’s surface for clues to how early planetary bodies evolved.

    Ahead of the mission, which is led by principal investigator Lindy Elkins-Tanton ’87, SM ’87, PhD ’02, planetary scientists at MIT and elsewhere have now provided a sneak peak of what the Psyche spacecraft might see when it reaches its destination.

    In a paper appearing today in the Journal of Geophysical Research: Planets, the team presents the most detailed maps of the asteroid’s surface properties to date, based on observations taken by a large array of ground telescopes in northern Chile. The maps reveal vast metal-rich regions sweeping across the asteroid’s surface, along with a large depression that appears to have a different surface texture between the interior and its rim; this difference could reflect a crater filled with finer sand and rimmed with rockier materials.

    Overall, Psyche’s surface was found to be surprisingly varied in its properties.

    The new maps hint at the asteroid’s history. Its rocky regions could be vestiges of an ancient mantle — similar in composition to the rocky outermost layer of Earth, Mars, and the asteroid Vesta — or the imprint of past impacts by space rocks. Finally, craters that contain metallic material support the idea proposed by previous studies that the asteroid may have experienced early eruptions of metallic lava as its ancient core cooled.

    “Psyche’s surface is very heterogeneous,” says lead author Saverio Cambioni, the Crosby Distinguished Postdoctoral Fellow in MIT’s Department of Earth, Atmospheric and Planetary Sciences (EAPS). “It’s an evolved surface, and these maps confirm that metal-rich asteroids are interesting, enigmatic worlds. It’s another reason to look forward to the Psyche mission going to the asteroid.”

    Cambioni’s co-authors are Katherine de Kleer, assistant professor of planetary science and astronomy at Caltech, and Michael Shepard, professor of environmental, geographical, and geological sciences at Bloomsburg University.
    ===
    Telescope Power

    The surface of Psyche has been a focus of numerous previous mapping efforts. Researchers have observed the asteroid using various telescopes to measure light emitted from the asteroid at infrared wavelengths, which carry information about Psyche’s surface composition. However, these studies could not spatially resolve variations in composition over the surface.

    Cambioni and his colleagues instead were able to see Psyche in finer detail, at a resolution of about 20 miles per pixel, using the combined power of the 66 radio antennas of the Atacama Large Millimeter/submillimeter Array (ALMA) in northern Chile.

    Each antenna of ALMA measures light emitted from an object at millimeter wavelengths, within a range that is sensitive to temperature and certain electrical properties of surface materials.

    “The signals of the ALMA antennas can be combined into a synthetic signal that’s equivalent to a telescope with a diameter of 16 kilometers (10 miles),” de Kleer says. “The larger the telescope, the higher the resolution.”

    On June 19, 2019, ALMA focused its entire array on Psyche as it orbited and rotated within the asteroid belt. De Kleer collected data during this period and converted it into a map of thermal emissions across the asteroid’s surface, which the team reported in a 2021 study. Those same data were used by Shepard to produce the most recent high-resolution 3D shape model of Psyche, also published in 2021.

    To catch a match

    In the new study, Cambioni ran simulations of Psyche to see which surface properties might best match and explain the measured thermal emissions. In each of hundreds of simulated scenarios, he set the asteroid’s surface with different combinations of materials, such as areas of different metal abundances. He modeled the asteroid’s rotation and measured how simulated materials on the asteroid would give off thermal emissions. Cambioni then looked for the simulated emissions that best matched the actual emissions measured by ALMA. That scenario, he reasoned, would reveal the likeliest map of the asteroid’s surface materials.

    “We ran these simulations area by area so we could catch differences in surface properties,” Cambioni says.

    The study produced detailed maps of Psyche’s surface properties, showing that the asteroid’s façade is likely covered in a large diversity of materials. The researchers confirmed that, overall, Psyche’s surface is rich in metals, but the abundance of metals and silicates varies across its surface. This may be a further hint that, early in its formation, the asteroid may have had a silicate-rich mantle that has since disappeared.

    They also found that, as the asteroid rotates, the material at the bottom of a large depression — likely a crater — changes temperature much faster than material along the rim. This suggests that the crater bottom is covered in “ponds” of fine-grained material, like sand on Earth, which heats up quickly, whereas the crater rims are composed of rockier, slower-to-warm materials.

    “Ponds of fine-grained materials have been seen on small asteroids, whose gravity is low enough for impacts to shake the surface and cause finer materials to pool,” Cambioni says. “But Psyche is a large body, so if fine-grained materials accumulated on the bottom of the depression, this is interesting and somewhat mysterious.”

    “These data show that Psyche’s surface is heterogeneous, with possible remarkable variations in composition,” says Simone Marchi, staff scientist at the Southwest Research Institute and a co-investigator on NASA’s Psyche mission, who was not involved in the current study. “One of the primary goals of the Psyche mission is to study the composition of the asteroid surface using its gamma rays and neutron spectrometer and a color imager. So, the possible presence of compositional heterogeneties is something that the Psyche Science Team is eager to study more.”

    This research was supported by the EAPS Crosby Distinguished Postodoctoral Fellowship, and in part by the Heising-Simons Foundation.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings
    Please help promote STEM in your local schools.

    Stem Education Coalition

    MIT Seal

    USPS “Forever” postage stamps celebrating Innovation at MIT.

    MIT Campus

    The Massachusetts Institute of Technology is a private land-grant research university in Cambridge, Massachusetts. The institute has an urban campus that extends more than a mile (1.6 km) alongside the Charles River. The institute also encompasses a number of major off-campus facilities such as the MIT Lincoln Laboratory , the MIT Bates Research and Engineering Center , and the Haystack Observatory , as well as affiliated laboratories such as the Broad Institute of MIT and Harvard and Whitehead Institute.

    Massachusettes Institute of Technology-Haystack Observatory Westford, Massachusetts, USA, Altitude 131 m (430 ft).

    Founded in 1861 in response to the increasing industrialization of the United States, Massachusetts Institute of Technology adopted a European polytechnic university model and stressed laboratory instruction in applied science and engineering. It has since played a key role in the development of many aspects of modern science, engineering, mathematics, and technology, and is widely known for its innovation and academic strength. It is frequently regarded as one of the most prestigious universities in the world.

    As of December 2020, 97 Nobel laureates, 26 Turing Award winners, and 8 Fields Medalists have been affiliated with MIT as alumni, faculty members, or researchers. In addition, 58 National Medal of Science recipients, 29 National Medals of Technology and Innovation recipients, 50 MacArthur Fellows, 80 Marshall Scholars, 3 Mitchell Scholars, 22 Schwarzman Scholars, 41 astronauts, and 16 Chief Scientists of the U.S. Air Force have been affiliated with The Massachusetts Institute of Technology . The university also has a strong entrepreneurial culture and MIT alumni have founded or co-founded many notable companies. Massachusetts Institute of Technology is a member of the Association of American Universities (AAU).

    Foundation and vision

    In 1859, a proposal was submitted to the Massachusetts General Court to use newly filled lands in Back Bay, Boston for a “Conservatory of Art and Science”, but the proposal failed. A charter for the incorporation of the Massachusetts Institute of Technology, proposed by William Barton Rogers, was signed by John Albion Andrew, the governor of Massachusetts, on April 10, 1861.

    Rogers, a professor from the University of Virginia , wanted to establish an institution to address rapid scientific and technological advances. He did not wish to found a professional school, but a combination with elements of both professional and liberal education, proposing that:

    “The true and only practicable object of a polytechnic school is, as I conceive, the teaching, not of the minute details and manipulations of the arts, which can be done only in the workshop, but the inculcation of those scientific principles which form the basis and explanation of them, and along with this, a full and methodical review of all their leading processes and operations in connection with physical laws.”

    The Rogers Plan reflected the German research university model, emphasizing an independent faculty engaged in research, as well as instruction oriented around seminars and laboratories.

    Early developments

    Two days after The Massachusetts Institute of Technology was chartered, the first battle of the Civil War broke out. After a long delay through the war years, MIT’s first classes were held in the Mercantile Building in Boston in 1865. The new institute was founded as part of the Morrill Land-Grant Colleges Act to fund institutions “to promote the liberal and practical education of the industrial classes” and was a land-grant school. In 1863 under the same act, the Commonwealth of Massachusetts founded the Massachusetts Agricultural College, which developed as the University of Massachusetts Amherst ). In 1866, the proceeds from land sales went toward new buildings in the Back Bay.

    The Massachusetts Institute of Technology was informally called “Boston Tech”. The institute adopted the European polytechnic university model and emphasized laboratory instruction from an early date. Despite chronic financial problems, the institute saw growth in the last two decades of the 19th century under President Francis Amasa Walker. Programs in electrical, chemical, marine, and sanitary engineering were introduced, new buildings were built, and the size of the student body increased to more than one thousand.

    The curriculum drifted to a vocational emphasis, with less focus on theoretical science. The fledgling school still suffered from chronic financial shortages which diverted the attention of the MIT leadership. During these “Boston Tech” years, Massachusetts Institute of Technology faculty and alumni rebuffed Harvard University president (and former MIT faculty) Charles W. Eliot’s repeated attempts to merge MIT with Harvard College’s Lawrence Scientific School. There would be at least six attempts to absorb MIT into Harvard. In its cramped Back Bay location, MIT could not afford to expand its overcrowded facilities, driving a desperate search for a new campus and funding. Eventually, the MIT Corporation approved a formal agreement to merge with Harvard, over the vehement objections of MIT faculty, students, and alumni. However, a 1917 decision by the Massachusetts Supreme Judicial Court effectively put an end to the merger scheme.

    In 1916, The Massachusetts Institute of Technology administration and the MIT charter crossed the Charles River on the ceremonial barge Bucentaur built for the occasion, to signify MIT’s move to a spacious new campus largely consisting of filled land on a one-mile-long (1.6 km) tract along the Cambridge side of the Charles River. The neoclassical “New Technology” campus was designed by William W. Bosworth and had been funded largely by anonymous donations from a mysterious “Mr. Smith”, starting in 1912. In January 1920, the donor was revealed to be the industrialist George Eastman of Rochester, New York, who had invented methods of film production and processing, and founded Eastman Kodak. Between 1912 and 1920, Eastman donated $20 million ($236.6 million in 2015 dollars) in cash and Kodak stock to MIT.

    Curricular reforms

    In the 1930s, President Karl Taylor Compton and Vice-President (effectively Provost) Vannevar Bush emphasized the importance of pure sciences like physics and chemistry and reduced the vocational practice required in shops and drafting studios. The Compton reforms “renewed confidence in the ability of the Institute to develop leadership in science as well as in engineering”. Unlike Ivy League schools, Massachusetts Institute of Technology catered more to middle-class families, and depended more on tuition than on endowments or grants for its funding. The school was elected to the Association of American Universities in 1934.

    Still, as late as 1949, the Lewis Committee lamented in its report on the state of education at The Massachusetts Institute of Technology that “the Institute is widely conceived as basically a vocational school”, a “partly unjustified” perception the committee sought to change. The report comprehensively reviewed the undergraduate curriculum, recommended offering a broader education, and warned against letting engineering and government-sponsored research detract from the sciences and humanities. The School of Humanities, Arts, and Social Sciences and the MIT Sloan School of Management were formed in 1950 to compete with the powerful Schools of Science and Engineering. Previously marginalized faculties in the areas of economics, management, political science, and linguistics emerged into cohesive and assertive departments by attracting respected professors and launching competitive graduate programs. The School of Humanities, Arts, and Social Sciences continued to develop under the successive terms of the more humanistically oriented presidents Howard W. Johnson and Jerome Wiesner between 1966 and 1980.

    The Massachusetts Institute of Technology‘s involvement in military science surged during World War II. In 1941, Vannevar Bush was appointed head of the federal Office of Scientific Research and Development and directed funding to only a select group of universities, including MIT. Engineers and scientists from across the country gathered at Massachusetts Institute of Technology ‘s Radiation Laboratory, established in 1940 to assist the British military in developing microwave radar. The work done there significantly affected both the war and subsequent research in the area. Other defense projects included gyroscope-based and other complex control systems for gunsight, bombsight, and inertial navigation under Charles Stark Draper’s Instrumentation Laboratory; the development of a digital computer for flight simulations under Project Whirlwind; and high-speed and high-altitude photography under Harold Edgerton. By the end of the war, The Massachusetts Institute of Technology became the nation’s largest wartime R&D contractor (attracting some criticism of Bush), employing nearly 4000 in the Radiation Laboratory alone and receiving in excess of $100 million ($1.2 billion in 2015 dollars) before 1946. Work on defense projects continued even after then. Post-war government-sponsored research at MIT included SAGE and guidance systems for ballistic missiles and Project Apollo.

    These activities affected The Massachusetts Institute of Technology profoundly. A 1949 report noted the lack of “any great slackening in the pace of life at the Institute” to match the return to peacetime, remembering the “academic tranquility of the prewar years”, though acknowledging the significant contributions of military research to the increased emphasis on graduate education and rapid growth of personnel and facilities. The faculty doubled and the graduate student body quintupled during the terms of Karl Taylor Compton, president of The Massachusetts Institute of Technology between 1930 and 1948; James Rhyne Killian, president from 1948 to 1957; and Julius Adams Stratton, chancellor from 1952 to 1957, whose institution-building strategies shaped the expanding university. By the 1950s, The Massachusetts Institute of Technology no longer simply benefited the industries with which it had worked for three decades, and it had developed closer working relationships with new patrons, philanthropic foundations and the federal government.

    In late 1960s and early 1970s, student and faculty activists protested against the Vietnam War and The Massachusetts Institute of Technology ‘s defense research. In this period Massachusetts Institute of Technology’s various departments were researching helicopters, smart bombs and counterinsurgency techniques for the war in Vietnam as well as guidance systems for nuclear missiles. The Union of Concerned Scientists was founded on March 4, 1969 during a meeting of faculty members and students seeking to shift the emphasis on military research toward environmental and social problems. The Massachusetts Institute of Technology ultimately divested itself from the Instrumentation Laboratory and moved all classified research off-campus to the MIT Lincoln Laboratory facility in 1973 in response to the protests. The student body, faculty, and administration remained comparatively unpolarized during what was a tumultuous time for many other universities. Johnson was seen to be highly successful in leading his institution to “greater strength and unity” after these times of turmoil. However six Massachusetts Institute of Technology students were sentenced to prison terms at this time and some former student leaders, such as Michael Albert and George Katsiaficas, are still indignant about MIT’s role in military research and its suppression of these protests. (Richard Leacock’s film, November Actions, records some of these tumultuous events.)

    In the 1980s, there was more controversy at The Massachusetts Institute of Technology over its involvement in SDI (space weaponry) and CBW (chemical and biological warfare) research. More recently, The Massachusetts Institute of Technology’s research for the military has included work on robots, drones and ‘battle suits’.

    Recent history

    The Massachusetts Institute of Technology has kept pace with and helped to advance the digital age. In addition to developing the predecessors to modern computing and networking technologies, students, staff, and faculty members at Project MAC, the Artificial Intelligence Laboratory, and the Tech Model Railroad Club wrote some of the earliest interactive computer video games like Spacewar! and created much of modern hacker slang and culture. Several major computer-related organizations have originated at MIT since the 1980s: Richard Stallman’s GNU Project and the subsequent Free Software Foundation were founded in the mid-1980s at the AI Lab; the MIT Media Lab was founded in 1985 by Nicholas Negroponte and Jerome Wiesner to promote research into novel uses of computer technology; the World Wide Web Consortium standards organization was founded at the Laboratory for Computer Science in 1994 by Tim Berners-Lee; the MIT OpenCourseWare project has made course materials for over 2,000 Massachusetts Institute of Technology classes available online free of charge since 2002; and the One Laptop per Child initiative to expand computer education and connectivity to children worldwide was launched in 2005.

    The Massachusetts Institute of Technology was named a sea-grant college in 1976 to support its programs in oceanography and marine sciences and was named a space-grant college in 1989 to support its aeronautics and astronautics programs. Despite diminishing government financial support over the past quarter century, MIT launched several successful development campaigns to significantly expand the campus: new dormitories and athletics buildings on west campus; the Tang Center for Management Education; several buildings in the northeast corner of campus supporting research into biology, brain and cognitive sciences, genomics, biotechnology, and cancer research; and a number of new “backlot” buildings on Vassar Street including the Stata Center. Construction on campus in the 2000s included expansions of the Media Lab, the Sloan School’s eastern campus, and graduate residences in the northwest. In 2006, President Hockfield launched the MIT Energy Research Council to investigate the interdisciplinary challenges posed by increasing global energy consumption.

    In 2001, inspired by the open source and open access movements, The Massachusetts Institute of Technology launched OpenCourseWare to make the lecture notes, problem sets, syllabi, exams, and lectures from the great majority of its courses available online for no charge, though without any formal accreditation for coursework completed. While the cost of supporting and hosting the project is high, OCW expanded in 2005 to include other universities as a part of the OpenCourseWare Consortium, which currently includes more than 250 academic institutions with content available in at least six languages. In 2011, The Massachusetts Institute of Technology announced it would offer formal certification (but not credits or degrees) to online participants completing coursework in its “MITx” program, for a modest fee. The “edX” online platform supporting MITx was initially developed in partnership with Harvard and its analogous “Harvardx” initiative. The courseware platform is open source, and other universities have already joined and added their own course content. In March 2009 the Massachusetts Institute of Technology faculty adopted an open-access policy to make its scholarship publicly accessible online.

    The Massachusetts Institute of Technology has its own police force. Three days after the Boston Marathon bombing of April 2013, MIT Police patrol officer Sean Collier was fatally shot by the suspects Dzhokhar and Tamerlan Tsarnaev, setting off a violent manhunt that shut down the campus and much of the Boston metropolitan area for a day. One week later, Collier’s memorial service was attended by more than 10,000 people, in a ceremony hosted by the Massachusetts Institute of Technology community with thousands of police officers from the New England region and Canada. On November 25, 2013, The Massachusetts Institute of Technology announced the creation of the Collier Medal, to be awarded annually to “an individual or group that embodies the character and qualities that Officer Collier exhibited as a member of The Massachusetts Institute of Technology community and in all aspects of his life”. The announcement further stated that “Future recipients of the award will include those whose contributions exceed the boundaries of their profession, those who have contributed to building bridges across the community, and those who consistently and selflessly perform acts of kindness”.

    In September 2017, the school announced the creation of an artificial intelligence research lab called the MIT-IBM Watson AI Lab. IBM will spend $240 million over the next decade, and the lab will be staffed by MIT and IBM scientists. In October 2018 MIT announced that it would open a new Schwarzman College of Computing dedicated to the study of artificial intelligence, named after lead donor and The Blackstone Group CEO Stephen Schwarzman. The focus of the new college is to study not just AI, but interdisciplinary AI education, and how AI can be used in fields as diverse as history and biology. The cost of buildings and new faculty for the new college is expected to be $1 billion upon completion.

    The Caltech/MIT Advanced aLIGO was designed and constructed by a team of scientists from California Institute of Technology , Massachusetts Institute of Technology, and industrial contractors, and funded by the National Science Foundation .

    Caltech /MIT Advanced aLigo

    It was designed to open the field of gravitational-wave astronomy through the detection of gravitational waves predicted by general relativity. Gravitational waves were detected for the first time by the LIGO detector in 2015. For contributions to the LIGO detector and the observation of gravitational waves, two Caltech physicists, Kip Thorne and Barry Barish, and Massachusetts Institute of Technology physicist Rainer Weiss won the Nobel Prize in physics in 2017. Weiss, who is also a Massachusetts Institute of Technology graduate, designed the laser interferometric technique, which served as the essential blueprint for the LIGO.

    The mission of The Massachusetts Institute of Technology is to advance knowledge and educate students in science, technology, and other areas of scholarship that will best serve the nation and the world in the twenty-first century. We seek to develop in each member of The Massachusetts Institute of Technology community the ability and passion to work wisely, creatively, and effectively for the betterment of humankind.

     
  • richardmitnick 12:50 pm on June 4, 2022 Permalink | Reply
    Tags: "A close encounter more than 10000 years ago stirred up spirals in an accretion disk", ALMA, , , , , The Shanghai Astronomical Observatory   

    From The Shanghai Astronomical Observatory: “A close encounter more than 10000 years ago stirred up spirals in an accretion disk” 

    From The Shanghai Astronomical Observatory

    At

    From The Chinese Academy of Sciences [中国科学院](CN)

    May 30, 2022

    Xing Lu,
    Shanghai Astronomical Observatory, CAS
    xinglu@shao.ac.cn

    Dr. Xing Lu, an associate researcher from Shanghai Astronomical Observatory, Chinese Academy of Sciences, together with his collaborators from Yunnan University, Harvard-Smithsonian Center for Astrophysics, and Max Planck Institute, have used high resolution observational data from the Atacama Large Millimeter/submillimeter Array (ALMA) to discover a massive protostellar disk in the Galactic Center.

    This disk has been perturbed by close encounter with a nearby object, leading to the formation of spiral arms. This finding demonstrates that the formation of massive stars could be similar to that of lower-mass stars, through accretion disks and flybys. The result is published in Nature Astronomy on May 30th.

    During the formation of stars, accretion disks will arise around new-born stars. These accretion disks, also known as ‘protostellar disks’, are an essential component in star formation. Accretion disks continuously feed gas into protostars from the environment. In this sense, they are stellar cradles where stars are born and raised. Accretion disks surrounding solar-like low-mass protostars have been extensively studied in the last few decades, leading to a wealth of observational and theoretical achievements. For massive protostars, especially early O-type ones of more than 30 solar masses, however, it is still unclear whether and how accretion disks play a role in their formation. These massive stars are far more luminous than the Sun, with intrinsic luminosities up to several hundreds of thousands of times the solar value, and strongly impact the environment of the entire Galaxy. Therefore, understanding the formation of massive stars is of great importance.

    At a distance of about 26,000 light years away from us, the Galactic Center is a unique and important star forming environment. The most well-known object here would certainly be the supermassive black hole Sgr A*. Other than that, there is a huge reservoir of dense molecular gas, mostly in the form of molecular hydrogen (H2), which is the raw material for star formation. The gas will start to form stars once gravitational collapse is initiated. However, the environment in the Galactic Center is unique, with strong turbulence, strong magnetic fields, and tidal forces from Sgr A*. Therefore, star formation in this region would be substantially affected, and may exhibit differences than the well-studied star forming regions in the solar neighborhood. Yet, the distance between the Galactic Center and us is huge, and there are complicated foreground contaminations. As a result, direct observations of star forming regions around the Galactic Center have been challenging. Astronomers have to choose telescopes that can provide very high resolutions and high sensitivities, so as to resolve details of star formation in the Galactic Center.

    The research team led by Dr. Lu have used the long baseline observations of the Atacama Large Millimeter/submillimeter Array (ALMA) to achieve a resolution of 40 milliarcseconds. At such a resolution, one can observe in Shanghai and easily spot a football hidden in Beijing. With these high resolution, high sensitivity ALMA observations, the researchers discovered an accretion disk in the Galactic Center. The disk has a diameter of about 4000 astronomical units, and is surrounding a forming early O-type star that is about 32 times the mass of the Sun. This system is among the most massive protostars with accretion disks, and represents the first direct imaging of a protostellar disk in the Galactic Center. The discovery suggests that the formation of massive early-O type stars does go through a phase with accretion disks involved, and such a conclusion is valid for the unique environment of the Galactic Center.

    What is more interesting is that the disk clearly displays two spiral arms. Such spiral arms are often found in spiral galaxies, but are rarely seen in protostellar disks. Usually, spiral arms could emerge in accretion disks thanks to the fragmentation induced by gravitational instabilities. However, the disk discovered in this research is hot and turbulent, thus is able to balance its own gravity. As such, the researchers proposed an alternative explanation: the spirals are induced by external perturbations. The researchers happen to detect an object of about 3 solar masses at several thousand astronomical units away from the disk, which could be the source of the external perturbations. To verify this proposition, the researchers examined several dozens of possible orbits of this object using analytical calculations, and found that only one of these orbits is able to perturb the disk. Then, they carried out a numerical simulation on the high-performance supercomputing platform of Shanghai Astronomical Observatory, to trace the trajectory of the intruding object, and successfully reproduced the entire history of the object flying by the disk more than 10,000 years ago and stirring up spirals in the disk (Figure 1). It is worth noting that such simulations are time consuming, taking up to one week to complete. However, the researchers had found the only suitable orbit through analytical solutions, and therefore they did not have to attempt different physical conditions back and forth, but simply ran one simulation and got the solution in one shot, which is an efficient approach. In conclusion, the nice match among analytical calculations, the numerical simulation, and the ALMA observations, provides robust evidence that the spiral arms in the disk are relics of the flyby of the intruding object.

    This finding clearly demonstrates that accretion disks at early evolutionary stages of star formation are subject to frequent dynamic processes such as flybys, which would substantially influence the formation of stars and planets. As such, one cannot regard accretion disks as isolated systems when studying their evolution, but should take dynamic interactions into account. It is interesting to note that flybys may have taken place in our own solar system too: a binary stellar system named the Scholz’s star flew by the Solar system about 70,000 years ago, probably penetrating through the Oort cloud and sending comets to the inner Solar system. The current study suggests that for more massive stars, especially in the high stellar density environment around the Galactic Center, such flybys should be frequent as well. “The formation of this massive protostar is similar to it lower-mass cousins like the Sun, with accretion disks and flyby events involved. Although stellar masses are different, certain physical mechanisms in star formation could be the same. This provides important clues to solving the mystery of massive star formation.” says Dr. Lu, “We have submitted new requests to observe with ALMA to further improve the resolution by a factor of three, which will push ALMA to its very limit, in order to recognize finer details in this unique accretion disk.”

    1
    Figure 1: The three plots starting from bottom left are snapshots from the numerical simulation, depicting the system right at the flyby event, 4000 years after, and 8000 years after, respectively. The top right image is from the ALMA observations, showing the disk with spirals and the two objects around it, corresponding to the system in the model 12,000 years after the flyby event.

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    The Chinese Academy of Sciences[中国科学院](CN) is the national academy for the natural sciences of the People’s Republic of China. It has historical origins in the Academia Sinica during the Republican era and was formerly also known by that name. Collectively known as the “Two Academies (两院)” along with the Chinese Academy of Engineering, it functions as the national scientific think tank and academic governing body, providing advisory and appraisal services on issues stemming from the national economy, social development, and science and technology progress. It is headquartered in Xicheng District, Beijing, with branch institutes all over mainland China. It has also created hundreds of commercial enterprises, Lenovo being one of the most famous.

    It is the world’s largest research organization, comprising around 60,000 researchers working in 114 institutes, and has been consistently ranked among the top research organizations around the world. It also holds the University of Science and Technology of China and the University of Chinese Academy of Sciences.

    The Chinese Academy of Sciences has been ranked the No. 1 research institute in the world by Nature Index since the list’s inception in 2016 by Nature Portfolio. It is the most productive institution publishing articles of sustainable development indexed in Web of Science from 1981 to 2018 among all universities and research institutions in the world.

    The Chinese Academy originated in the Academia Sinica founded, in 1928, by the Republic of China. After the Communist Party took control of mainland China in 1949, the residual of Academia Sinica was renamed Chinese Academy of Sciences (CAS), while others relocated to Taiwan.

    The Chinese Academy of Sciences has six academic divisions:

    Chemistry (化学部)
    Information Technological Sciences (信息技术科学部)
    Earth Sciences (地学部)
    Life Sciences and Medical Sciences (生命科学和医学学部)
    Mathematics and Physics (数学物理学部)
    Technological Sciences (技术科学部)

    The CAS has thirteen regional branches, in Beijing, Shenyang, Changchun, Shanghai, Nanjing, Wuhan, Guangzhou, Chengdu, Kunming, Xi’an, Lanzhou, Hefei and Xinjiang. It has over one hundred institutes and four universities (the University of Science and Technology of China at Hefei, Anhui, the University of the Chinese Academy of Sciences in Beijing, ShanghaiTech University, and Shenzhen Institute of Adavanced Technology). Backed by the institutes of CAS, UCAS is headquartered in Beijing, with graduate education bases in Shanghai, Chengdu, Wuhan, Guangzhou and Lanzhou, four Science Libraries of Chinese Academy of Sciences, three technology support centers and two news and publishing units. These CAS branches and offices are located in 20 provinces and municipalities throughout China. CAS has invested in or created over 430 science- and technology-based enterprises in eleven industries, including eight companies listed on stock exchanges.

    Being granted a Fellowship of the Academy represents the highest level of national honor for Chinese scientists. The CAS membership system includes Academicians (院士), Emeritus Academicians (荣誉院士) and Foreign Academicians (外籍院士).

    The Chinese Academy of Sciences was ranked #1 in the 2016, 2017, 2018, 2019, and 2020 Nature Index Annual Tables, which measure the largest contributors to papers published in 82 leading journals.

    Research institutes

    Beijing Branch
    University of the Chinese Academy of Sciences (UCAS)
    Academy of Mathematics and Systems Science
    Institute of Acoustics (IOA)
    Institute of Atmospheric Physics
    Institute of Botany, Chinese Academy of Sciences
    Institute of Physics (IOPCAS)
    Institute of Semiconductors
    Institute of Electrical Engineering (IEE)
    Institute of Information Engineering (IIE)
    Institute of Theoretical Physics
    Institute of High Energy Physics
    Institute of Biophysics
    Institute of Genetics and Developmental Biology
    Institute of Electronics
    National Astronomical Observatories
    Institute of Computing Technology
    Institute of Software
    Institute of Automation
    Beijing Institute of Genomics
    Institute of Geographic Sciences and Natural Resources
    Institute of Geology and Geophysics (IGG)
    Institute of Remote Sensing and Digital Earth
    Institute of Tibetan Plateau Research
    Institute of Vertebrate Paleontology and Paleoanthropology
    National Center for Nanoscience and Technology
    Institute of Policy and Management
    Institute of Psychology
    Institute of Zoology
    Changchun Branch
    Changchun Institute of Optics, Fine Mechanics and Physics
    Changchun Institute of Applied Chemistry
    Northeast Institute of Geography and Agroecology
    Changchun Observatory
    Chengdu Branch
    Institute of Mountain Hazards and Environment
    Chengdu Institute of Biology
    Institute of Optics and Electronics
    Chengdu Institute of Organic Chemistry
    Institute of Computer Application
    Chongqing Institute of Green and Intelligent Technology
    Guangzhou Branch
    South China Botanical Garden
    Shenzhen Institutes of Advanced Technology
    South China Sea Institute of Oceanology
    Guangzhou Institute of Energy Conversion
    Guangzhou Institute of Geochemistry
    Guangzhou Institute of Biomedicine and Health
    Guiyang Branch
    Institute of Geochemistry
    Hefei Branch
    Hefei Institutes of Physical Science
    University of Science and Technology of China
    Kunming Branch
    Kunming Institute of Botany
    Kunming Institute of Zoology
    Xishuangbanna Tropical Botanical Garden
    Institute of Geochemistry
    Yunnan Astronomical Observatory
    Lanzhou Branch
    Institute of Modern Physics
    Lanzhou Institute of Chemical Physics
    Lanzhou Institute of Geology
    Northwest Institute of Plateau Biology
    Northwest Institute of Eco-Environment and Resources
    Qinghai Institute of Salt Lakes Research
    Nanjing Branch
    Purple Mountain Observatory (Zijinshan Astronomical Observatory)
    Institute of Soil Science
    Nanjing Institute of Geology and Palaeontology
    Nanjing Institute of Geography and Limnology
    Nanjing Institute of Astronomical Optics and Technology
    Suzhou Institute of Nano-tech and Nano-bionics (SINANO)
    Suzhou Institute of Biomedical Engineering and Technology (SIBET)
    Nanjing Botanical Garden, Memorial Sun Yat-Sen (Institute of Botany, Jiangsu Province and Chinese Academy of Science)
    University of Chinese Academy of Sciences, Nanjing College
    Shanghai Branch
    Shanghai Astronomical Observatory
    Shanghai Institute of Microsystem and Information Technology
    Shanghai Institute of Technical Physics
    Shanghai Institute of Optics and Fine Mechanics
    Shanghai Institute of Ceramics
    Shanghai Institute of Organic Chemistry
    Shanghai Institute of Applied Physics
    Shanghai Institutes for Biological Sciences
    Shanghai Institute of Materia Medica
    Institut Pasteur of Shanghai
    Shanghai Advanced Research Institute, CAS
    Institute of Neuroscience (ION)
    ShanghaiTech University
    Shenyang Branch
    Institute of Metal Research
    Shenyang Institute of Automation
    Shenyang Institute of Applied Ecology, formerly the Institute of Forestry and Pedology
    Shenyang Institute of Computing Technology
    Dalian Institute of Chemical Physics
    Qingdao Institute of Oceanology
    Qingdao Institute of Bioenergy and Bioprocess Technology
    Yantai Institute of Coastal Zone Research
    Taiyuan Branch
    Shanxi Institute of Coal Chemistry (ICCCAS)
    Wuhan Branch
    Wuhan Institute of Rock and Soil Mechanics
    Wuhan Institute of Physics and Mathematics
    Wuhan Institute of Virology
    Institute of Geodesy and Geophysics
    Institute of Hydrobiology
    Wuhan Botanical Garden
    Xinjiang Branch
    Xinjiang Technical Institute of Physics and Chemistry
    Xinjiang Institute of Ecology and Geography
    Xi’an Branch
    Xi’an Institute of Optics and Precision Mechanics
    National Time Service Center
    Institute of Earth Environment

     
  • richardmitnick 8:03 am on June 3, 2022 Permalink | Reply
    Tags: "Hubble goes galactic for bird watching", ALMA, , , , , , , ,   

    From Hubblesite and ESA/Hubble via Manu Garcia- a friend from IAC-Institute of Astrophysics of the Canaries[Instituto de Astrofísica de Canarias](ES): “Hubble goes galactic for bird watching” 

    National Aeronautics and Space Administration/European Space Agency [La Agencia Espacial Europea] [Agence spatiale européenne] [Europäische Weltraumorganisation](EU) Hubble Space Telescope.

    From Hubblesite and ESA/Hubble

    via


    Manu Garcia, a friend from IAC-Institute of Astrophysics of the Canaries[Instituto de Astrofísica de Canarias](ES).

    The universe around us.
    Astronomy, everything you wanted to know about our local universe and never dared to ask.

    6.3.22

    1

    This NASA/ESA Hubble Space Telescope image shows the barred spiral galaxy NGC 7496, which lies more than 24 million light-years away in the constellation Grus. This constellation, whose Latin name means crane, is one of four constellations known collectively as the Birds of the South. The others are Pavo, Phoenix, and Tucana, which represent a peacock, a phoenix, and a toucan, respectively. The rest of the night sky is also home to a flock of ornithological constellations, including an eagle (Aquilla), a swan (Cygnus), a raven (Corvus), and a dove (Columba).

    This image comes from a collection of observations that delve deeper into the relationship between young stars and the cool, dense clouds of gas in which they form. In addition to observations with Hubble’s Wide Field Camera 3 [below] and Advanced Camera for Surveys [below], the astronomers behind this project collected data using the Atacama Large Millimeter/submillimeter Array (ALMA), one of the world’s largest radio telescopes.

    In addition to shedding light on the speed and efficiency of star formation in a variety of galactic environments, this project is also creating a trove of data incorporating Hubble and ALMA observations. This trove of data from two of the world’s most capable observatories will contribute to broader research on star formation, as well as pave the way for future science with the James Webb Space Telescope. Credit: ESA/Hubble & NASA, J. Lee and the PHANGS-HST team, Acknowledgment: J. Schmidt the astronomers behind this project collected data using the Atacama Large Millimeter/submillimeter Array (ALMA), one of the largest radio telescopes in the world.

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition
    The NASA/ESA Hubble Space Telescope is a space telescope that was launched into low Earth orbit in 1990 and remains in operation. It was not the first space telescope, but it is one of the largest and most versatile, renowned both as a vital research tool and as a public relations boon for astronomy. The Hubble telescope is named after astronomer Edwin Hubble and is one of NASA’s Great Observatories, along with the NASA Compton Gamma Ray Observatory, the Chandra X-ray Observatory, and the NASA Spitzer Infrared Space Telescope.

    National Aeronautics Space Agency Compton Gamma Ray Observatory
    National Aeronautics and Space Administration Chandra X-ray telescope.
    National Aeronautics and Space AdministrationSpitzer Infrared Apace Telescope no longer in service. Launched in 2003 and retired on 30 January 2020.

    Edwin Hubble at Caltech Palomar Samuel Oschin 48 inch Telescope Credit: Emilio Segre Visual Archives/AIP/SPL.

    Edwin Hubble looking through the 100-inch Hooker telescope at Mount Wilson in Southern California, 1929 discovers the Universe is Expanding. Credit: Margaret Bourke-White/Time & Life Pictures/Getty Images.

    Hubble features a 2.4-meter (7.9 ft) mirror, and its four main instruments observe in the ultraviolet, visible, and near-infrared regions of the electromagnetic spectrum. Hubble’s orbit outside the distortion of Earth’s atmosphere allows it to capture extremely high-resolution images with substantially lower background light than ground-based telescopes. It has recorded some of the most detailed visible light images, allowing a deep view into space. Many Hubble observations have led to breakthroughs in astrophysics, such as determining the rate of expansion of the universe.

    The Hubble telescope was built by the United States space agency National Aeronautics Space Agency with contributions from the The European Space Agency [La Agencia Espacial Europea] [Agence spatiale européenne][Europäische Weltraumorganisation](EU). The Space Telescope Science Institute (STScI) selects Hubble’s targets and processes the resulting data, while the NASA Goddard Space Flight Center controls the spacecraft. Space telescopes were proposed as early as 1923. Hubble was funded in the 1970s with a proposed launch in 1983, but the project was beset by technical delays, budget problems, and the 1986 Challenger disaster. It was finally launched by Space Shuttle Discovery in 1990, but its main mirror had been ground incorrectly, resulting in spherical aberration that compromised the telescope’s capabilities. The optics were corrected to their intended quality by a servicing mission in 1993.

    Hubble is the only telescope designed to be maintained in space by astronauts. Five Space Shuttle missions have repaired, upgraded, and replaced systems on the telescope, including all five of the main instruments. The fifth mission was initially canceled on safety grounds following the Columbia disaster (2003), but NASA administrator Michael D. Griffin approved the fifth servicing mission which was completed in 2009. The telescope was still operating as of April 24, 2020, its 30th anniversary, and could last until 2030–2040. One successor to the Hubble telescope is the National Aeronautics Space Agency/European Space Agency [La Agencia Espacial Europea] [Agence spatiale européenne](EU)/Canadian Space Agency(CA) Webb Infrared Space Telescope.

    National Aeronautics Space Agency/European Space Agency [La Agencia Espacial Europea] [Agence spatiale européenne][Europäische Weltraumorganisation](EU)/ Canadian Space Agency [Agence Spatiale Canadienne](CA) Webb Infrared Space Telescope James Webb Space Telescope annotated . Launched December 25, 2021, ten years late.

    Proposals and precursors

    In 1923, Hermann Oberth—considered a father of modern rocketry, along with Robert H. Goddard and Konstantin Tsiolkovsky—published Die Rakete zu den Planetenräumen (“The Rocket into Planetary Space“), which mentioned how a telescope could be propelled into Earth orbit by a rocket.

    The history of the Hubble Space Telescope can be traced back as far as 1946, to astronomer Lyman Spitzer’s paper entitled Astronomical advantages of an extraterrestrial observatory. In it, he discussed the two main advantages that a space-based observatory would have over ground-based telescopes. First, the angular resolution (the smallest separation at which objects can be clearly distinguished) would be limited only by diffraction, rather than by the turbulence in the atmosphere, which causes stars to twinkle, known to astronomers as seeing. At that time ground-based telescopes were limited to resolutions of 0.5–1.0 arcseconds, compared to a theoretical diffraction-limited resolution of about 0.05 arcsec for an optical telescope with a mirror 2.5 m (8.2 ft) in diameter. Second, a space-based telescope could observe infrared and ultraviolet light, which are strongly absorbed by the atmosphere.

    Spitzer devoted much of his career to pushing for the development of a space telescope. In 1962, a report by the U.S. National Academy of Sciences recommended development of a space telescope as part of the space program, and in 1965 Spitzer was appointed as head of a committee given the task of defining scientific objectives for a large space telescope.

    Space-based astronomy had begun on a very small-scale following World War II, as scientists made use of developments that had taken place in rocket technology. The first ultraviolet spectrum of the Sun was obtained in 1946, and the National Aeronautics and Space Administration launched the Orbiting Solar Observatory (OSO) to obtain UV, X-ray, and gamma-ray spectra in 1962.
    National Aeronautics Space Agency Orbiting Solar Observatory

    An orbiting solar telescope was launched in 1962 by the United Kingdom as part of the Ariel space program, and in 1966 NASA launched the first Orbiting Astronomical Observatory (OAO) mission. OAO-1’s battery failed after three days, terminating the mission. It was followed by OAO-2, which carried out ultraviolet observations of stars and galaxies from its launch in 1968 until 1972, well beyond its original planned lifetime of one year.

    The OSO and OAO missions demonstrated the important role space-based observations could play in astronomy. In 1968, NASA developed firm plans for a space-based reflecting telescope with a mirror 3 m (9.8 ft) in diameter, known provisionally as the Large Orbiting Telescope or Large Space Telescope (LST), with a launch slated for 1979. These plans emphasized the need for crewed maintenance missions to the telescope to ensure such a costly program had a lengthy working life, and the concurrent development of plans for the reusable Space Shuttle indicated that the technology to allow this was soon to become available.

    Quest for funding

    The continuing success of the OAO program encouraged increasingly strong consensus within the astronomical community that the LST should be a major goal. In 1970, NASA established two committees, one to plan the engineering side of the space telescope project, and the other to determine the scientific goals of the mission. Once these had been established, the next hurdle for NASA was to obtain funding for the instrument, which would be far more costly than any Earth-based telescope. The U.S. Congress questioned many aspects of the proposed budget for the telescope and forced cuts in the budget for the planning stages, which at the time consisted of very detailed studies of potential instruments and hardware for the telescope. In 1974, public spending cuts led to Congress deleting all funding for the telescope project.
    In response a nationwide lobbying effort was coordinated among astronomers. Many astronomers met congressmen and senators in person, and large-scale letter-writing campaigns were organized. The National Academy of Sciences published a report emphasizing the need for a space telescope, and eventually the Senate agreed to half the budget that had originally been approved by Congress.

    The funding issues led to something of a reduction in the scale of the project, with the proposed mirror diameter reduced from 3 m to 2.4 m, both to cut costs and to allow a more compact and effective configuration for the telescope hardware. A proposed precursor 1.5 m (4.9 ft) space telescope to test the systems to be used on the main satellite was dropped, and budgetary concerns also prompted collaboration with the European Space Agency. ESA agreed to provide funding and supply one of the first-generation instruments for the telescope, as well as the solar cells that would power it, and staff to work on the telescope in the United States, in return for European astronomers being guaranteed at least 15% of the observing time on the telescope. Congress eventually approved funding of US$36 million for 1978, and the design of the LST began in earnest, aiming for a launch date of 1983. In 1983 the telescope was named after Edwin Hubble, who confirmed one of the greatest scientific discoveries of the 20th century, made by Georges Lemaitre, that the universe is expanding.

    Construction and engineering

    Once the Space Telescope project had been given the go-ahead, work on the program was divided among many institutions. NASA Marshall Space Flight Center was given responsibility for the design, development, and construction of the telescope, while Goddard Space Flight Center was given overall control of the scientific instruments and ground-control center for the mission. MSFC commissioned the optics company Perkin-Elmer to design and build the Optical Telescope Assembly (OTA) and Fine Guidance Sensors for the space telescope. Lockheed was commissioned to construct and integrate the spacecraft in which the telescope would be housed.

    Optical Telescope Assembly

    Optically, the HST is a Cassegrain reflector of Ritchey–Chrétien design, as are most large professional telescopes. This design, with two hyperbolic mirrors, is known for good imaging performance over a wide field of view, with the disadvantage that the mirrors have shapes that are hard to fabricate and test. The mirror and optical systems of the telescope determine the final performance, and they were designed to exacting specifications. Optical telescopes typically have mirrors polished to an accuracy of about a tenth of the wavelength of visible light, but the Space Telescope was to be used for observations from the visible through the ultraviolet (shorter wavelengths) and was specified to be diffraction limited to take full advantage of the space environment. Therefore, its mirror needed to be polished to an accuracy of 10 nanometers, or about 1/65 of the wavelength of red light. On the long wavelength end, the OTA was not designed with optimum IR performance in mind—for example, the mirrors are kept at stable (and warm, about 15 °C) temperatures by heaters. This limits Hubble’s performance as an infrared telescope.

    Perkin-Elmer intended to use custom-built and extremely sophisticated computer-controlled polishing machines to grind the mirror to the required shape. However, in case their cutting-edge technology ran into difficulties, NASA demanded that PE sub-contract to Kodak to construct a back-up mirror using traditional mirror-polishing techniques. (The team of Kodak and Itek also bid on the original mirror polishing work. Their bid called for the two companies to double-check each other’s work, which would have almost certainly caught the polishing error that later caused such problems.) The Kodak mirror is now on permanent display at the National Air and Space Museum. An Itek mirror built as part of the effort is now used in the 2.4 m telescope at the Magdalena Ridge Observatory.

    Construction of the Perkin-Elmer mirror began in 1979, starting with a blank manufactured by Corning from their ultra-low expansion glass. To keep the mirror’s weight to a minimum it consisted of top and bottom plates, each one inch (25 mm) thick, sandwiching a honeycomb lattice. Perkin-Elmer simulated microgravity by supporting the mirror from the back with 130 rods that exerted varying amounts of force. This ensured the mirror’s final shape would be correct and to specification when finally deployed. Mirror polishing continued until May 1981. NASA reports at the time questioned Perkin-Elmer’s managerial structure, and the polishing began to slip behind schedule and over budget. To save money, NASA halted work on the back-up mirror and put the launch date of the telescope back to October 1984. The mirror was completed by the end of 1981; it was washed using 2,400 US gallons (9,100 L) of hot, deionized water and then received a reflective coating of 65 nm-thick aluminum and a protective coating of 25 nm-thick magnesium fluoride.

    Doubts continued to be expressed about Perkin-Elmer’s competence on a project of this importance, as their budget and timescale for producing the rest of the OTA continued to inflate. In response to a schedule described as “unsettled and changing daily”, NASA postponed the launch date of the telescope until April 1985. Perkin-Elmer’s schedules continued to slip at a rate of about one month per quarter, and at times delays reached one day for each day of work. NASA was forced to postpone the launch date until March and then September 1986. By this time, the total project budget had risen to US$1.175 billion.

    Spacecraft systems

    The spacecraft in which the telescope and instruments were to be housed was another major engineering challenge. It would have to withstand frequent passages from direct sunlight into the darkness of Earth’s shadow, which would cause major changes in temperature, while being stable enough to allow extremely accurate pointing of the telescope. A shroud of multi-layer insulation keeps the temperature within the telescope stable and surrounds a light aluminum shell in which the telescope and instruments sit. Within the shell, a graphite-epoxy frame keeps the working parts of the telescope firmly aligned. Because graphite composites are hygroscopic, there was a risk that water vapor absorbed by the truss while in Lockheed’s clean room would later be expressed in the vacuum of space; resulting in the telescope’s instruments being covered by ice. To reduce that risk, a nitrogen gas purge was performed before launching the telescope into space.

    While construction of the spacecraft in which the telescope and instruments would be housed proceeded somewhat more smoothly than the construction of the OTA, Lockheed still experienced some budget and schedule slippage, and by the summer of 1985, construction of the spacecraft was 30% over budget and three months behind schedule. An MSFC report said Lockheed tended to rely on NASA directions rather than take their own initiative in the construction.

    Computer systems and data processing

    The two initial, primary computers on the HST were the 1.25 MHz DF-224 system, built by Rockwell Autonetics, which contained three redundant CPUs, and two redundant NSSC-1 (NASA Standard Spacecraft Computer, Model 1) systems, developed by Westinghouse and GSFC using diode–transistor logic (DTL). A co-processor for the DF-224 was added during Servicing Mission 1 in 1993, which consisted of two redundant strings of an Intel-based 80386 processor with an 80387-math co-processor. The DF-224 and its 386 co-processor were replaced by a 25 MHz Intel-based 80486 processor system during Servicing Mission 3A in 1999. The new computer is 20 times faster, with six times more memory, than the DF-224 it replaced. It increases throughput by moving some computing tasks from the ground to the spacecraft and saves money by allowing the use of modern programming languages.

    Additionally, some of the science instruments and components had their own embedded microprocessor-based control systems. The MATs (Multiple Access Transponder) components, MAT-1 and MAT-2, utilize Hughes Aircraft CDP1802CD microprocessors. The Wide Field and Planetary Camera (WFPC) also utilized an RCA 1802 microprocessor (or possibly the older 1801 version). The WFPC-1 was replaced by the WFPC-2 [below] during Servicing Mission 1 in 1993, which was then replaced by the Wide Field Camera 3 (WFC3) [below] during Servicing Mission 4 in 2009.

    Initial instruments

    When launched, the HST carried five scientific instruments: the Wide Field and Planetary Camera (WF/PC), Goddard High Resolution Spectrograph (GHRS), High Speed Photometer (HSP), Faint Object Camera (FOC) and the Faint Object Spectrograph (FOS). WF/PC was a high-resolution imaging device primarily intended for optical observations. It was built by NASA JPL-Caltech, and incorporated a set of 48 filters isolating spectral lines of particular astrophysical interest. The instrument contained eight charge-coupled device (CCD) chips divided between two cameras, each using four CCDs. Each CCD has a resolution of 0.64 megapixels. The wide field camera (WFC) covered a large angular field at the expense of resolution, while the planetary camera (PC) took images at a longer effective focal length than the WF chips, giving it a greater magnification.

    The GHRS was a spectrograph designed to operate in the ultraviolet. It was built by the Goddard Space Flight Center and could achieve a spectral resolution of 90,000. Also optimized for ultraviolet observations were the FOC and FOS, which were capable of the highest spatial resolution of any instruments on Hubble. Rather than CCDs these three instruments used photon-counting digicons as their detectors. The FOC was constructed by ESA, while the University of California, San Diego, and Martin Marietta Corporation built the FOS.

    The final instrument was the HSP, designed and built at the University of Wisconsin–Madison. It was optimized for visible and ultraviolet light observations of variable stars and other astronomical objects varying in brightness. It could take up to 100,000 measurements per second with a photometric accuracy of about 2% or better.

    HST’s guidance system can also be used as a scientific instrument. Its three Fine Guidance Sensors (FGS) are primarily used to keep the telescope accurately pointed during an observation, but can also be used to carry out extremely accurate astrometry; measurements accurate to within 0.0003 arcseconds have been achieved.

    Ground support

    The Space Telescope Science Institute is responsible for the scientific operation of the telescope and the delivery of data products to astronomers. STScI is operated by the Association of Universities for Research in Astronomy and is physically located in Baltimore, Maryland on the Homewood campus of Johns Hopkins University, one of the 39 U.S. universities and seven international affiliates that make up the AURA consortium. STScI was established in 1981 after something of a power struggle between NASA and the scientific community at large. NASA had wanted to keep this function in-house, but scientists wanted it to be based in an academic establishment. The Space Telescope European Coordinating Facility, established at Garching bei München near Munich in 1984, provided similar support for European astronomers until 2011, when these activities were moved to the European Space Astronomy Centre.

    One rather complex task that falls to STScI is scheduling observations for the telescope. Hubble is in a low-Earth orbit to enable servicing missions, but this means most astronomical targets are occulted by the Earth for slightly less than half of each orbit. Observations cannot take place when the telescope passes through the South Atlantic Anomaly due to elevated radiation levels, and there are also sizable exclusion zones around the Sun (precluding observations of Mercury), Moon and Earth. The solar avoidance angle is about 50°, to keep sunlight from illuminating any part of the OTA. Earth and Moon avoidance keeps bright light out of the FGSs, and keeps scattered light from entering the instruments. If the FGSs are turned off, the Moon and Earth can be observed. Earth observations were used very early in the program to generate flat-fields for the WFPC1 instrument. There is a so-called continuous viewing zone (CVZ), at roughly 90° to the plane of Hubble’s orbit, in which targets are not occulted for long periods.

    Challenger disaster, delays, and eventual launch

    By January 1986, the planned launch date of October looked feasible, but the Challenger explosion brought the U.S. space program to a halt, grounding the Shuttle fleet and forcing the launch of Hubble to be postponed for several years. The telescope had to be kept in a clean room, powered up and purged with nitrogen, until a launch could be rescheduled. This costly situation (about US$6 million per month) pushed the overall costs of the project even higher. This delay did allow time for engineers to perform extensive tests, swap out a possibly failure-prone battery, and make other improvements. Furthermore, the ground software needed to control Hubble was not ready in 1986, and was barely ready by the 1990 launch.

    Eventually, following the resumption of shuttle flights in 1988, the launch of the telescope was scheduled for 1990. On April 24, 1990, Space Shuttle Discovery successfully launched it during the STS-31 mission.

    From its original total cost estimate of about US$400 million, the telescope cost about US$4.7 billion by the time of its launch. Hubble’s cumulative costs were estimated to be about US$10 billion in 2010, twenty years after launch.

    List of Hubble instruments

    Hubble accommodates five science instruments at a given time, plus the Fine Guidance Sensors, which are mainly used for aiming the telescope but are occasionally used for scientific astrometry measurements. Early instruments were replaced with more advanced ones during the Shuttle servicing missions. COSTAR was a corrective optics device rather than a science instrument, but occupied one of the five instrument bays.
    Since the final servicing mission in 2009, the four active instruments have been ACS, COS, STIS and WFC3. NICMOS is kept in hibernation, but may be revived if WFC3 were to fail in the future.

    Advanced Camera for Surveys (ACS; 2002–present)
    Cosmic Origins Spectrograph (COS; 2009–present)
    Corrective Optics Space Telescope Axial Replacement (COSTAR; 1993–2009)
    Faint Object Camera (FOC; 1990–2002)
    Faint Object Spectrograph (FOS; 1990–1997)
    Fine Guidance Sensor (FGS; 1990–present)
    Goddard High Resolution Spectrograph (GHRS/HRS; 1990–1997)
    High Speed Photometer (HSP; 1990–1993)
    Near Infrared Camera and Multi-Object Spectrometer (NICMOS; 1997–present, hibernating since 2008)
    Space Telescope Imaging Spectrograph (STIS; 1997–present (non-operative 2004–2009))
    Wide Field and Planetary Camera (WFPC; 1990–1993)
    Wide Field and Planetary Camera 2 (WFPC2; 1993–2009)
    Wide Field Camera 3 (WFC3; 2009–present)

    Of the former instruments, three (COSTAR, FOS and WFPC2) are displayed in the Smithsonian National Air and Space Museum. The FOC is in the Dornier Museum, Germany. The HSP is in the Space Place at the University of Wisconsin–Madison. The first WFPC was dismantled, and some components were then re-used in WFC3.

    Flawed mirror

    Within weeks of the launch of the telescope, the returned images indicated a serious problem with the optical system. Although the first images appeared to be sharper than those of ground-based telescopes, Hubble failed to achieve a final sharp focus and the best image quality obtained was drastically lower than expected. Images of point sources spread out over a radius of more than one arcsecond, instead of having a point spread function (PSF) concentrated within a circle 0.1 arcseconds (485 nrad) in diameter, as had been specified in the design criteria.

    Analysis of the flawed images revealed that the primary mirror had been polished to the wrong shape. Although it was believed to be one of the most precisely figured optical mirrors ever made, smooth to about 10 nanometers, the outer perimeter was too flat by about 2200 nanometers (about 1⁄450 mm or 1⁄11000 inch). This difference was catastrophic, introducing severe spherical aberration, a flaw in which light reflecting off the edge of a mirror focuses on a different point from the light reflecting off its center.

    The effect of the mirror flaw on scientific observations depended on the particular observation—the core of the aberrated PSF was sharp enough to permit high-resolution observations of bright objects, and spectroscopy of point sources was affected only through a sensitivity loss. However, the loss of light to the large, out-of-focus halo severely reduced the usefulness of the telescope for faint objects or high-contrast imaging. This meant nearly all the cosmological programs were essentially impossible, since they required observation of exceptionally faint objects. This led politicians to question NASA’s competence, scientists to rue the cost which could have gone to more productive endeavors, and comedians to make jokes about NASA and the telescope − in the 1991 comedy The Naked Gun 2½: The Smell of Fear, in a scene where historical disasters are displayed, Hubble is pictured with RMS Titanic and LZ 129 Hindenburg. Nonetheless, during the first three years of the Hubble mission, before the optical corrections, the telescope still carried out a large number of productive observations of less demanding targets. The error was well characterized and stable, enabling astronomers to partially compensate for the defective mirror by using sophisticated image processing techniques such as deconvolution.

    Origin of the problem

    A commission headed by Lew Allen, director of the Jet Propulsion Laboratory, was established to determine how the error could have arisen. The Allen Commission found that a reflective null corrector, a testing device used to achieve a properly shaped non-spherical mirror, had been incorrectly assembled—one lens was out of position by 1.3 mm (0.051 in). During the initial grinding and polishing of the mirror, Perkin-Elmer analyzed its surface with two conventional refractive null correctors. However, for the final manufacturing step (figuring), they switched to the custom-built reflective null corrector, designed explicitly to meet very strict tolerances. The incorrect assembly of this device resulted in the mirror being ground very precisely but to the wrong shape. A few final tests, using the conventional null correctors, correctly reported spherical aberration. But these results were dismissed, thus missing the opportunity to catch the error, because the reflective null corrector was considered more accurate.

    The commission blamed the failings primarily on Perkin-Elmer. Relations between NASA and the optics company had been severely strained during the telescope construction, due to frequent schedule slippage and cost overruns. NASA found that Perkin-Elmer did not review or supervise the mirror construction adequately, did not assign its best optical scientists to the project (as it had for the prototype), and in particular did not involve the optical designers in the construction and verification of the mirror. While the commission heavily criticized Perkin-Elmer for these managerial failings, NASA was also criticized for not picking up on the quality control shortcomings, such as relying totally on test results from a single instrument.

    Design of a solution

    Many feared that Hubble would be abandoned. The design of the telescope had always incorporated servicing missions, and astronomers immediately began to seek potential solutions to the problem that could be applied at the first servicing mission, scheduled for 1993. While Kodak had ground a back-up mirror for Hubble, it would have been impossible to replace the mirror in orbit, and too expensive and time-consuming to bring the telescope back to Earth for a refit. Instead, the fact that the mirror had been ground so precisely to the wrong shape led to the design of new optical components with exactly the same error but in the opposite sense, to be added to the telescope at the servicing mission, effectively acting as “spectacles” to correct the spherical aberration.

    The first step was a precise characterization of the error in the main mirror. Working backwards from images of point sources, astronomers determined that the conic constant of the mirror as built was −1.01390±0.0002, instead of the intended −1.00230. The same number was also derived by analyzing the null corrector used by Perkin-Elmer to figure the mirror, as well as by analyzing interferograms obtained during ground testing of the mirror.

    Because of the way the HST’s instruments were designed, two different sets of correctors were required. The design of the Wide Field and Planetary Camera 2, already planned to replace the existing WF/PC, included relay mirrors to direct light onto the four separate charge-coupled device (CCD) chips making up its two cameras. An inverse error built into their surfaces could completely cancel the aberration of the primary. However, the other instruments lacked any intermediate surfaces that could be figured in this way, and so required an external correction device.

    The Corrective Optics Space Telescope Axial Replacement (COSTAR) system was designed to correct the spherical aberration for light focused at the FOC, FOS, and GHRS. It consists of two mirrors in the light path with one ground to correct the aberration. To fit the COSTAR system onto the telescope, one of the other instruments had to be removed, and astronomers selected the High Speed Photometer to be sacrificed. By 2002, all the original instruments requiring COSTAR had been replaced by instruments with their own corrective optics. COSTAR was removed and returned to Earth in 2009 where it is exhibited at the National Air and Space Museum. The area previously used by COSTAR is now occupied by the Cosmic Origins Spectrograph.

    NASA COSTAR

    NASA COSTAR installation

    Servicing missions and new instruments

    Servicing Mission 1

    The first Hubble serving mission was scheduled for 1993 before the mirror problem was discovered. It assumed greater importance, as the astronauts would need to do extensive work to install corrective optics; failure would have resulted in either abandoning Hubble or accepting its permanent disability. Other components failed before the mission, causing the repair cost to rise to $500 million (not including the cost of the shuttle flight). A successful repair would help demonstrate the viability of building Space Station Alpha, however.

    STS-49 in 1992 demonstrated the difficulty of space work. While its rescue of Intelsat 603 received praise, the astronauts had taken possibly reckless risks in doing so. Neither the rescue nor the unrelated assembly of prototype space station components occurred as the astronauts had trained, causing NASA to reassess planning and training, including for the Hubble repair. The agency assigned to the mission Story Musgrave—who had worked on satellite repair procedures since 1976—and six other experienced astronauts, including two from STS-49. The first mission director since Project Apollo would coordinate a crew with 16 previous shuttle flights. The astronauts were trained to use about a hundred specialized tools.

    Heat had been the problem on prior spacewalks, which occurred in sunlight. Hubble needed to be repaired out of sunlight. Musgrave discovered during vacuum training, seven months before the mission, that spacesuit gloves did not sufficiently protect against the cold of space. After STS-57 confirmed the issue in orbit, NASA quickly changed equipment, procedures, and flight plan. Seven total mission simulations occurred before launch, the most thorough preparation in shuttle history. No complete Hubble mockup existed, so the astronauts studied many separate models (including one at the Smithsonian) and mentally combined their varying and contradictory details. Service Mission 1 flew aboard Endeavour in December 1993, and involved installation of several instruments and other equipment over ten days.

    Most importantly, the High-Speed Photometer was replaced with the COSTAR corrective optics package, and WFPC was replaced with the Wide Field and Planetary Camera 2 (WFPC2) with an internal optical correction system. The solar arrays and their drive electronics were also replaced, as well as four gyroscopes in the telescope pointing system, two electrical control units and other electrical components, and two magnetometers. The onboard computers were upgraded with added coprocessors, and Hubble’s orbit was boosted.

    On January 13, 1994, NASA declared the mission a complete success and showed the first sharper images. The mission was one of the most complex performed up until that date, involving five long extra-vehicular activity periods. Its success was a boon for NASA, as well as for the astronomers who now had a more capable space telescope.

    Servicing Mission 2

    Servicing Mission 2, flown by Discovery in February 1997, replaced the GHRS and the FOS with the Space Telescope Imaging Spectrograph (STIS) and the Near Infrared Camera and Multi-Object Spectrometer (NICMOS), replaced an Engineering and Science Tape Recorder with a new Solid State Recorder, and repaired thermal insulation. NICMOS contained a heat sink of solid nitrogen to reduce the thermal noise from the instrument, but shortly after it was installed, an unexpected thermal expansion resulted in part of the heat sink coming into contact with an optical baffle. This led to an increased warming rate for the instrument and reduced its original expected lifetime of 4.5 years to about two years.

    Servicing Mission 3A

    Servicing Mission 3A, flown by Discovery, took place in December 1999, and was a split-off from Servicing Mission 3 after three of the six onboard gyroscopes had failed. The fourth failed a few weeks before the mission, rendering the telescope incapable of performing scientific observations. The mission replaced all six gyroscopes, replaced a Fine Guidance Sensor and the computer, installed a Voltage/temperature Improvement Kit (VIK) to prevent battery overcharging, and replaced thermal insulation blankets.

    Servicing Mission 3B

    Servicing Mission 3B flown by Columbia in March 2002 saw the installation of a new instrument, with the FOC (which, except for the Fine Guidance Sensors when used for astrometry, was the last of the original instruments) being replaced by the Advanced Camera for Surveys (ACS). This meant COSTAR was no longer required, since all new instruments had built-in correction for the main mirror aberration. The mission also revived NICMOS by installing a closed-cycle cooler and replaced the solar arrays for the second time, providing 30 percent more power.

    Servicing Mission 4

    Plans called for Hubble to be serviced in February 2005, but the Columbia disaster in 2003, in which the orbiter disintegrated on re-entry into the atmosphere, had wide-ranging effects on the Hubble program. NASA Administrator Sean O’Keefe decided all future shuttle missions had to be able to reach the safe haven of the International Space Station should in-flight problems develop. As no shuttles were capable of reaching both HST and the space station during the same mission, future crewed service missions were canceled. This decision was criticized by numerous astronomers who felt Hubble was valuable enough to merit the human risk. HST’s planned successor, the James Webb Telescope (JWST), as of 2004 was not expected to launch until at least 2011. A gap in space-observing capabilities between a decommissioning of Hubble and the commissioning of a successor was of major concern to many astronomers, given the significant scientific impact of HST. The consideration that JWST will not be located in low Earth orbit, and therefore cannot be easily upgraded or repaired in the event of an early failure, only made concerns more acute. On the other hand, many astronomers felt strongly that servicing Hubble should not take place if the expense were to come from the JWST budget.

    In January 2004, O’Keefe said he would review his decision to cancel the final servicing mission to HST, due to public outcry and requests from Congress for NASA to look for a way to save it. The National Academy of Sciences convened an official panel, which recommended in July 2004 that the HST should be preserved despite the apparent risks. Their report urged “NASA should take no actions that would preclude a space shuttle servicing mission to the Hubble Space Telescope”. In August 2004, O’Keefe asked Goddard Space Flight Center to prepare a detailed proposal for a robotic service mission. These plans were later canceled, the robotic mission being described as “not feasible”. In late 2004, several Congressional members, led by Senator Barbara Mikulski, held public hearings and carried on a fight with much public support (including thousands of letters from school children across the U.S.) to get the Bush Administration and NASA to reconsider the decision to drop plans for a Hubble rescue mission.

    The nomination in April 2005 of a new NASA Administrator, Michael D. Griffin, changed the situation, as Griffin stated he would consider a crewed servicing mission. Soon after his appointment Griffin authorized Goddard to proceed with preparations for a crewed Hubble maintenance flight, saying he would make the final decision after the next two shuttle missions. In October 2006 Griffin gave the final go-ahead, and the 11-day mission by Atlantis was scheduled for October 2008. Hubble’s main data-handling unit failed in September 2008, halting all reporting of scientific data until its back-up was brought online on October 25, 2008. Since a failure of the backup unit would leave the HST helpless, the service mission was postponed to incorporate a replacement for the primary unit.

    Servicing Mission 4 (SM4), flown by Atlantis in May 2009, was the last scheduled shuttle mission for HST. SM4 installed the replacement data-handling unit, repaired the ACS and STIS systems, installed improved nickel hydrogen batteries, and replaced other components including all six gyroscopes. SM4 also installed two new observation instruments—Wide Field Camera 3 (WFC3) and the Cosmic Origins Spectrograph (COS)—and the Soft Capture and Rendezvous System, which will enable the future rendezvous, capture, and safe disposal of Hubble by either a crewed or robotic mission. Except for the ACS’s High Resolution Channel, which could not be repaired and was disabled, the work accomplished during SM4 rendered the telescope fully functional.

    Major projects

    Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey [CANDELS]

    The survey “aims to explore galactic evolution in the early Universe, and the very first seeds of cosmic structure at less than one billion years after the Big Bang.” The CANDELS project site describes the survey’s goals as the following:

    The Cosmic Assembly Near-IR Deep Extragalactic Legacy Survey is designed to document the first third of galactic evolution from z = 8 to 1.5 via deep imaging of more than 250,000 galaxies with WFC3/IR and ACS. It will also find the first Type Ia SNe beyond z > 1.5 and establish their accuracy as standard candles for cosmology. Five premier multi-wavelength sky regions are selected; each has multi-wavelength data from Spitzer and other facilities, and has extensive spectroscopy of the brighter galaxies. The use of five widely separated fields mitigates cosmic variance and yields statistically robust and complete samples of galaxies down to 109 solar masses out to z ~ 8.

    Frontier Fields program

    The program, officially named Hubble Deep Fields Initiative 2012, is aimed to advance the knowledge of early galaxy formation by studying high-redshift galaxies in blank fields with the help of gravitational lensing to see the “faintest galaxies in the distant universe”. The Frontier Fields web page describes the goals of the program being:

    To reveal hitherto inaccessible populations of z = 5–10 galaxies that are ten to fifty times fainter intrinsically than any presently known
    To solidify our understanding of the stellar masses and star formation histories of sub-L* galaxies at the earliest times
    To provide the first statistically meaningful morphological characterization of star forming galaxies at z > 5
    To find z > 8 galaxies stretched out enough by cluster lensing to discern internal structure and/or magnified enough by cluster lensing for spectroscopic follow-up.

    Cosmic Evolution Survey (COSMOS)

    The Cosmic Evolution Survey (COSMOS) is an astronomical survey designed to probe the formation and evolution of galaxies as a function of both cosmic time (redshift) and the local galaxy environment. The survey covers a two square degree equatorial field with spectroscopy and X-ray to radio imaging by most of the major space-based telescopes and a number of large ground based telescopes, making it a key focus region of extragalactic astrophysics. COSMOS was launched in 2006 as the largest project pursued by the Hubble Space Telescope at the time, and still is the largest continuous area of sky covered for the purposes of mapping deep space in blank fields, 2.5 times the area of the moon on the sky and 17 times larger than the largest of the CANDELS regions. The COSMOS scientific collaboration that was forged from the initial COSMOS survey is the largest and longest-running extragalactic collaboration, known for its collegiality and openness. The study of galaxies in their environment can be done only with large areas of the sky, larger than a half square degree. More than two million galaxies are detected, spanning 90% of the age of the Universe. The COSMOS collaboration is led by Caitlin Casey, Jeyhan Kartaltepe, and Vernesa Smolcic and involves more than 200 scientists in a dozen countries.

    Important discoveries

    Hubble has helped resolve some long-standing problems in astronomy, while also raising new questions. Some results have required new theories to explain them.

    Age of the universe

    Among its primary mission targets was to measure distances to Cepheid variable stars more accurately than ever before, and thus constrain the value of the Hubble constant, the measure of the rate at which the universe is expanding, which is also related to its age. Before the launch of HST, estimates of the Hubble constant typically had errors of up to 50%, but Hubble measurements of Cepheid variables in the Virgo Cluster and other distant galaxy clusters provided a measured value with an accuracy of ±10%, which is consistent with other more accurate measurements made since Hubble’s launch using other techniques. The estimated age is now about 13.7 billion years, but before the Hubble Telescope, scientists predicted an age ranging from 10 to 20 billion years.

    Expansion of the universe

    While Hubble helped to refine estimates of the age of the universe, it also cast doubt on theories about its future. Astronomers from the High-z Supernova Search Team and the Supernova Cosmology Project used ground-based telescopes and HST to observe distant supernovae and uncovered evidence that, far from decelerating under the influence of gravity, the expansion of the universe may in fact be accelerating. Three members of these two groups have subsequently been awarded Nobel Prizes for their discovery.

    Saul Perlmutter [The Supernova Cosmology Project] shared the 2006 Shaw Prize in Astronomy, the 2011 Nobel Prize in Physics, and the 2015 Breakthrough Prize in Fundamental Physics with Brian P. Schmidt and Adam Riess [The High-z Supernova Search Team] for providing evidence that the expansion of the universe is accelerating.

    The cause of this acceleration remains poorly understood; the most common cause attributed is Dark Energy.

    Black holes

    The high-resolution spectra and images provided by the HST have been especially well-suited to establishing the prevalence of black holes in the center of nearby galaxies. While it had been hypothesized in the early 1960s that black holes would be found at the centers of some galaxies, and astronomers in the 1980s identified a number of good black hole candidates, work conducted with Hubble shows that black holes are probably common to the centers of all galaxies. The Hubble programs further established that the masses of the nuclear black holes and properties of the galaxies are closely related. The legacy of the Hubble programs on black holes in galaxies is thus to demonstrate a deep connection between galaxies and their central black holes.

    Extending visible wavelength images

    A unique window on the Universe enabled by Hubble are the Hubble Deep Field, Hubble Ultra-Deep Field, and Hubble Extreme Deep Field images, which used Hubble’s unmatched sensitivity at visible wavelengths to create images of small patches of sky that are the deepest ever obtained at optical wavelengths. The images reveal galaxies billions of light years away, and have generated a wealth of scientific papers, providing a new window on the early Universe. The Wide Field Camera 3 improved the view of these fields in the infrared and ultraviolet, supporting the discovery of some of the most distant objects yet discovered, such as MACS0647-JD.

    The non-standard object SCP 06F6 was discovered by the Hubble Space Telescope in February 2006.

    On March 3, 2016, researchers using Hubble data announced the discovery of the farthest known galaxy to date: GN-z11. The Hubble observations occurred on February 11, 2015, and April 3, 2015, as part of the CANDELS/GOODS-North surveys.

    Solar System discoveries

    HST has also been used to study objects in the outer reaches of the Solar System, including the dwarf planets Pluto and Eris.

    The collision of Comet Shoemaker-Levy 9 with Jupiter in 1994 was fortuitously timed for astronomers, coming just a few months after Servicing Mission 1 had restored Hubble’s optical performance. Hubble images of the planet were sharper than any taken since the passage of Voyager 2 in 1979, and were crucial in studying the dynamics of the collision of a comet with Jupiter, an event believed to occur once every few centuries.

    During June and July 2012, U.S. astronomers using Hubble discovered Styx, a tiny fifth moon orbiting Pluto.

    In March 2015, researchers announced that measurements of aurorae around Ganymede, one of Jupiter’s moons, revealed that it has a subsurface ocean. Using Hubble to study the motion of its aurorae, the researchers determined that a large saltwater ocean was helping to suppress the interaction between Jupiter’s magnetic field and that of Ganymede. The ocean is estimated to be 100 km (60 mi) deep, trapped beneath a 150 km (90 mi) ice crust.

    From June to August 2015, Hubble was used to search for a Kuiper belt object (KBO) target for the New Horizons Kuiper Belt Extended Mission (KEM) when similar searches with ground telescopes failed to find a suitable target.

    National Aeronautics Space Agency/New Horizons spacecraft.

    This resulted in the discovery of at least five new KBOs, including the eventual KEM target, 486958 Arrokoth, that New Horizons performed a close fly-by of on January 1, 2019.

    In August 2020, taking advantage of a total lunar eclipse, astronomers using NASA’s Hubble Space Telescope have detected Earth’s own brand of sunscreen – ozone – in our atmosphere. This method simulates how astronomers and astrobiology researchers will search for evidence of life beyond Earth by observing potential “biosignatures” on exoplanets (planets around other stars).
    Hubble and ALMA image of MACS J1149.5+2223.

    Supernova reappearance

    On December 11, 2015, Hubble captured an image of the first-ever predicted reappearance of a supernova, dubbed “Refsdal”, which was calculated using different mass models of a galaxy cluster whose gravity is warping the supernova’s light. The supernova was previously seen in November 2014 behind galaxy cluster MACS J1149.5+2223 as part of Hubble’s Frontier Fields program. Astronomers spotted four separate images of the supernova in an arrangement known as an “Einstein Cross”.

    The light from the cluster has taken about five billion years to reach Earth, though the supernova exploded some 10 billion years ago. Based on early lens models, a fifth image was predicted to reappear by the end of 2015. The detection of Refsdal’s reappearance in December 2015 served as a unique opportunity for astronomers to test their models of how mass, especially dark matter, is distributed within this galaxy cluster.

    Impact on astronomy

    Many objective measures show the positive impact of Hubble data on astronomy. Over 15,000 papers based on Hubble data have been published in peer-reviewed journals, and countless more have appeared in conference proceedings. Looking at papers several years after their publication, about one-third of all astronomy papers have no citations, while only two percent of papers based on Hubble data have no citations. On average, a paper based on Hubble data receives about twice as many citations as papers based on non-Hubble data. Of the 200 papers published each year that receive the most citations, about 10% are based on Hubble data.

    Although the HST has clearly helped astronomical research, its financial cost has been large. A study on the relative astronomical benefits of different sizes of telescopes found that while papers based on HST data generate 15 times as many citations as a 4 m (13 ft) ground-based telescope such as the William Herschel Telescope, the HST costs about 100 times as much to build and maintain.

    Isaac Newton Group 4.2 meter William Herschel Telescope at Roque de los Muchachos Observatory | Instituto de Astrofísica de Canarias • IAC(ES) on La Palma in the Canary Islands(ES), 2,396 m (7,861 ft)

    Deciding between building ground- versus space-based telescopes is complex. Even before Hubble was launched, specialized ground-based techniques such as aperture masking interferometry had obtained higher-resolution optical and infrared images than Hubble would achieve, though restricted to targets about 108 times brighter than the faintest targets observed by Hubble. Since then, advances in “adaptive optics” have extended the high-resolution imaging capabilities of ground-based telescopes to the infrared imaging of faint objects.

    Glistening against the awesome backdrop of the night sky above ESO’s Paranal Observatory, four laser beams project out into the darkness from Unit Telescope 4 UT4 of the VLT, a major asset of the Adaptive Optics system.

    UCO KeckLaser Guide Star Adaptive Optics on two 10 meter Keck Observatory telescopes, Maunakea Hawaii, altitude 4,207 m (13,802 ft).

    The usefulness of adaptive optics versus HST observations depends strongly on the particular details of the research questions being asked. In the visible bands, adaptive optics can correct only a relatively small field of view, whereas HST can conduct high-resolution optical imaging over a wide field. Only a small fraction of astronomical objects are accessible to high-resolution ground-based imaging; in contrast Hubble can perform high-resolution observations of any part of the night sky, and on objects that are extremely faint.

    Impact on aerospace engineering

    In addition to its scientific results, Hubble has also made significant contributions to aerospace engineering, in particular the performance of systems in low Earth orbit. These insights result from Hubble’s long lifetime on orbit, extensive instrumentation, and return of assemblies to the Earth where they can be studied in detail. In particular, Hubble has contributed to studies of the behavior of graphite composite structures in vacuum, optical contamination from residual gas and human servicing, radiation damage to electronics and sensors, and the long-term behavior of multi-layer insulation. One lesson learned was that gyroscopes assembled using pressurized oxygen to deliver suspension fluid were prone to failure due to electric wire corrosion. Gyroscopes are now assembled using pressurized nitrogen. Another is that optical surfaces in LEO can have surprisingly long lifetimes; Hubble was only expected to last 15 years before the mirror became unusable, but after 14 years there was no measurable degradation. Finally, Hubble servicing missions, particularly those that serviced components not designed for in-space maintenance, have contributed towards the development of new tools and techniques for on-orbit repair.

    Archives

    All Hubble data is eventually made available via the Mikulski Archive for Space Telescopes at STScI, CADC and ESA/ESAC. Data is usually proprietary—available only to the principal investigator (PI) and astronomers designated by the PI—for twelve months after being taken. The PI can apply to the director of the STScI to extend or reduce the proprietary period in some circumstances.

    Observations made on Director’s Discretionary Time are exempt from the proprietary period, and are released to the public immediately. Calibration data such as flat fields and dark frames are also publicly available straight away. All data in the archive is in the FITS format, which is suitable for astronomical analysis but not for public use. The Hubble Heritage Project processes and releases to the public a small selection of the most striking images in JPEG and TIFF formats.

    Outreach activities

    It has always been important for the Space Telescope to capture the public’s imagination, given the considerable contribution of taxpayers to its construction and operational costs. After the difficult early years when the faulty mirror severely dented Hubble’s reputation with the public, the first servicing mission allowed its rehabilitation as the corrected optics produced numerous remarkable images.

    Several initiatives have helped to keep the public informed about Hubble activities. In the United States, outreach efforts are coordinated by the Space Telescope Science Institute (STScI) Office for Public Outreach, which was established in 2000 to ensure that U.S. taxpayers saw the benefits of their investment in the space telescope program. To that end, STScI operates the HubbleSite.org website. The Hubble Heritage Project, operating out of the STScI, provides the public with high-quality images of the most interesting and striking objects observed. The Heritage team is composed of amateur and professional astronomers, as well as people with backgrounds outside astronomy, and emphasizes the aesthetic nature of Hubble images. The Heritage Project is granted a small amount of time to observe objects which, for scientific reasons, may not have images taken at enough wavelengths to construct a full-color image.

    Since 1999, the leading Hubble outreach group in Europe has been the Hubble European Space Agency Information Centre (HEIC). This office was established at the Space Telescope European Coordinating Facility in Munich, Germany. HEIC’s mission is to fulfill HST outreach and education tasks for the European Space Agency. The work is centered on the production of news and photo releases that highlight interesting Hubble results and images. These are often European in origin, and so increase awareness of both ESA’s Hubble share (15%) and the contribution of European scientists to the observatory. ESA produces educational material, including a videocast series called Hubblecast designed to share world-class scientific news with the public.

    The Hubble Space Telescope has won two Space Achievement Awards from the Space Foundation, for its outreach activities, in 2001 and 2010.

    A replica of the Hubble Space Telescope is on the courthouse lawn in Marshfield, Missouri, the hometown of namesake Edwin P. Hubble.

    Major Instrumentation

    Hubble WFPC2 no longer in service.

    Wide Field Camera 3 [WFC3]

    National Aeronautics Space Agency/The European Space Agency [La Agencia Espacial Europea] [Agence spatiale européenne][Europäische Weltraumorganisation](EU) Hubble Wide Field Camera 3

    Advanced Camera for Surveys [ACS]

    National Aeronautics Space Agency/European Space Agency [La Agencia Espacial Europea] [Agence spatiale européenne][Europäische Weltraumorganisation](EU) NASA/ESA Hubble Space Telescope Advanced Camera for Surveys

    Cosmic Origins Spectrograph [COS]

    National Aeronautics Space Agency Cosmic Origins Spectrograph.

    The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA’s Goddard Space Flight Center manages the telescope. The Space Telescope Science Institute (STScI), is a free-standing science center, located on the campus of The Johns Hopkins University and operated by the Association of Universities for Research in Astronomy for NASA, conducts Hubble science operations.

    ESA50 Logo large

    The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation’s civilian space program and for aeronautics and aerospace research.

    President Dwight D. Eisenhower established the National Aeronautics and Space Administration (NASA) in 1958 with a distinctly civilian (rather than military) orientation encouraging peaceful applications in space science. The National Aeronautics and Space Act was passed on July 29, 1958, disestablishing NASA’s predecessor, the National Advisory Committee for Aeronautics (NACA). The new agency became operational on October 1, 1958.

    Since that time, most U.S. space exploration efforts have been led by NASA, including the Apollo moon-landing missions, the Skylab space station, and later the Space Shuttle. Currently, NASA is supporting the International Space Station and is overseeing the development of the Orion Multi-Purpose Crew Vehicle and Commercial Crew vehicles. The agency is also responsible for the Launch Services Program (LSP) which provides oversight of launch operations and countdown management for unmanned NASA launches. Most recently, NASA announced a new Space Launch System that it said would take the agency’s astronauts farther into space than ever before and lay the cornerstone for future human space exploration efforts by the U.S.

    NASA science is focused on better understanding Earth through the Earth Observing System, advancing heliophysics through the efforts of the Science Mission Directorate’s Heliophysics Research Program, exploring bodies throughout the Solar System with advanced robotic missions such as New Horizons, and researching astrophysics topics, such as the Big Bang, through the Great Observatories [NASA/ESA Hubble, NASA Chandra, NASA Spitzer, and associated programs.] NASA shares data with various national and international organizations such as from [JAXA]Greenhouse Gases Observing Satellite.

     
  • richardmitnick 11:37 am on May 31, 2022 Permalink | Reply
    Tags: "Unknown structure in galaxy revealed by high contrast imaging", ALMA, , , , , Quasar 3C273,   

    From ALMA (CL): “Unknown structure in galaxy revealed by high contrast imaging” 

    From ALMA (CL)

    Nicolás Lira
    Education and Public Outreach Coordinator
    Joint ALMA Observatory, Santiago – Chile
    Phone: +56 2 2467 6519
    Cell phone: +56 9 9445 7726
    Email: nicolas.lira@alma.cl

    Junko Ueda
    Public Information Officer
    NAOJ
    Email: junko.ueda@nao.ac.jp

    Bárbara Ferreira
    ESO Public Information Officer
    Garching bei München, Germany
    Phone: +49 89 3200 6670
    Email: pio@eso.org

    Amy C. Oliver
    Public Information & News Manager
    National Radio Astronomical Observatory (NRAO), USA
    Phone: +1 434 242 9584
    Email: aoliver@nrao.edu

    31 May, 2022

    All general references:
    ALMA Observatory (CL) http://www.almaobservatory.org/

    European Southern Observatory(EU) http://www.eso.org/public/

    National Astronomical Observatory of Japan(JP) http://www.nao.ac.jp/en/

    National Radio Astronomy Observatory(US) https://public.nrao.edu/
    Full identification of an astronomical asset will be presented once in the first instance of that asset.

    1
    Artist’s impression of a giant galaxy with a high-energy jet. Credit: ALMA (ESO/NAOJ/NRAO)

    2
    Quasar 3C273 observed by the Hubble Space Telescope (HST) (left). The exceeding brightness results in radial leaks of light created by light scattered by the telescope. At the lower right is a high-energy jet released by the gas around the central black hole. | Radio image of 3C273 observed by ALMA, showing the faint and extended radio emission (in blue-white color) around the nucleus (right). The bright central source has been subtracted from the image. The same jet as the image on the left can be seen in orange. Credit: Komugi et al., NASA/ESA Hubble Space Telescope.

    As a result of achieving high imaging dynamic range, a team of astronomers in Japan has discovered for the first time a faint radio emission covering a giant galaxy with an energetic black hole at its center. The radio emission is released from gas created directly by the central black hole. The team expects to understand how a black hole interacts with its host galaxy by applying the same technique to other quasars.

    3C273, which lies at a distance of 2.4 billion light-years from Earth, is a quasar. A quasar is the nucleus of a galaxy believed to house a massive black hole at its center, which swallows its surrounding material, giving off enormous radiation. Contrary to its bland name, 3C273 is the first quasar ever discovered, the brightest, and the best studied. It is one of the most frequently observed sources with telescopes because it can be used as a standard of position in the sky: in other words, 3C273 is a radio lighthouse.

    When you see a car’s headlight, the dazzling brightness makes it challenging to see the darker surroundings. The same thing happens to telescopes when you observe bright objects. Dynamic range is the contrast between the most brilliant and darkest tones in an image. You need a high dynamic range to reveal both the bright and dark parts in a telescope’s single shot. ALMA can regularly attain imaging dynamic ranges up to around 100, but commercially available digital cameras would typically have a dynamic range of several thousands. Radio telescopes aren’t very good at seeing objects with significant contrast.

    3C273 has been known for decades as the most famous quasar, but knowledge has been concentrated on its bright central nuclei, where most radio waves come from. However, much less has been known about its host galaxy itself because the combination of the faint and diffuse galaxy with the 3C273 nucleus required such high dynamic ranges to detect. The research team used a technique called self-calibration to reduce the leakage of radio waves from 3C273 to the galaxy, which used 3C273 itself to correct for the effects of Earth’s atmospheric fluctuations on the telescope system. They reached an imaging dynamic range of 85000, an ALMA record for extragalactic objects.

    As a result of achieving high imaging dynamic range, the team discovered the faint radio emission extending for tens of thousands of light-years over the host galaxy of 3C273. Radio emission around quasars typically suggests synchrotron emission, which comes from highly energetic events like bursts of star formation or ultra-fast jets emanating from the central nucleus. A synchrotron jet exists in 3C273 as well, seen in the lower right of the images. An essential characteristic of synchrotron emission is its brightness changes with frequency, but the faint radio emission discovered by the team had constant brightness irrespective of the radio frequency. After considering alternative mechanisms, the team found that this faint and extended radio emission came from hydrogen gas in the galaxy energized directly by the 3C273 nucleus. This is the first time that radio waves from such a mechanism are found to extend for tens of thousands of light-years in the host galaxy of a quasar. Astronomers had overlooked this phenomenon for decades in this iconic cosmic lighthouse.

    So why is this discovery so important? It has been a big mystery in galactic astronomy whether the energy from a quasar nucleus can be strong enough to deprive the galaxy’s ability to form stars. The faint radio emission may help to solve it. Hydrogen gas is an essential ingredient in creating stars, but if such an intense light shines on it that the gas is disassembled (ionized), no stars can be born. To study whether this process is happening around quasars, astronomers have used optical light emitted by ionized gas. The problem working with optical light is that cosmic dust absorbs the light along the way to the telescope, so it is difficult to know how much light the gas gives off.

    Moreover, the mechanism responsible for giving off optical light is complex, forcing astronomers to make a lot of assumptions. The radio waves discovered in this study come from the same gas due to simple processes and are not absorbed by dust. Using radio waves makes measuring ionized gas created by 3C273’s nucleus much easier. In this study, the astronomers found that at least 7% of the light from 3C273 was absorbed by gas in the host galaxy, creating ionized gas amounting to 10-100 billion times the sun’s mass. However, 3C273 had a lot of gas just before the formation of stars, so as a whole, it didn’t look like star formation was strongly suppressed by the nucleus.

    “This discovery provides a new avenue to studying problems previously tackled using observations by optical light,” says Shinya Komugi, an associate professor at Kogakuin University and lead author of the study published in The Astrophysical Journal. “By applying the same technique to other quasars, we expect to understand how a galaxy evolves through its interaction with the central nucleus.”

    Additional Information

    The team is composed of Shinya Komugi (Kogakuin University), Yoshiki Toba (National Astronomical Observatory of Japan [NAOJ]), Yoshiki Matsuoka (Ehime University), Toshiki Saito (NAOJ), and Takuji Yamashita (NAOJ).

    This research was supported by JSPS KAKENHI Grant Numbers JP20K04015, JP21K13968, and JP19K14759.

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    The Atacama Large Millimeter/submillimeter Array (ALMA) (CL) , an international astronomy facility, is a partnership of Europe, North America and East Asia in cooperation with the Republic of Chile. ALMA is funded in Europe by the European Organization for Astronomical Research in the Southern Hemisphere (ESO) (EU), in North America by the U.S. National Science Foundation (NSF) in cooperation with the National Research Council of Canada (NRC) (CA) and the National Science Council of Taiwan (NSC) and in East Asia by the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Academia Sinica (AS) in Taiwan.

    ALMA construction and operations are led on behalf of Europe by European Southern Observatory(EU), on behalf of North America by the National Radio Astronomy Observatory (NRAO), which is managed by Associated Universities, Inc. (US) and on behalf of East Asia by the National Astronomical Observatory of Japan (NAOJ). The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.
    NRAO Small
    ESO 50 Large

    The antennas can be moved across the desert plateau over distances from 150 m to 16 km, which will give ALMA a powerful variable “zoom”, similar in its concept to that employed at the centimetre-wavelength Very Large Array (VLA) site in New Mexico, United States.

    The high sensitivity is mainly achieved through the large numbers of antenna dishes that will make up the array.

    The telescopes were provided by the European, North American and East Asian partners of ALMA. The American and European partners each provided twenty-five 12-meter diameter antennas, that compose the main array. The participating East Asian countries are contributing 16 antennas (four 12-meter diameter and twelve 7-meter diameter antennas) in the form of the Atacama Compact Array (ACA), which is part of the enhanced ALMA.

    By using smaller antennas than the main ALMA array, larger fields of view can be imaged at a given frequency using ACA. Placing the antennas closer together enables the imaging of sources of larger angular extent. The ACA works together with the main array in order to enhance the latter’s wide-field imaging capability.

    ALMA has its conceptual roots in three astronomical projects — the Millimeter Array (MMA) of the United States, the Large Southern Array (LSA) of Europe, and the Large Millimeter Array (LMA) of Japan.

    The first step toward the creation of what would become ALMA came in 1997, when the National Radio Astronomy Observatory (NRAO) and the European Southern Observatory (ESO) agreed to pursue a common project that merged the MMA and LSA. The merged array combined the sensitivity of the LSA with the frequency coverage and superior site of the MMA. ESO and NRAO worked together in technical, science, and management groups to define and organize a joint project between the two observatories with participation by Canada and Spain (the latter became a member of ESO later).

    A series of resolutions and agreements led to the choice of “Atacama Large Millimeter Array”, or ALMA, as the name of the new array in March 1999 and the signing of the ALMA Agreement on 25 February 2003, between the North American and European parties. (“Alma” means “soul” in Spanish and “learned” or “knowledgeable” in Arabic.) Following mutual discussions over several years, the ALMA Project received a proposal from the National Astronomical Observatory of Japan (NAOJ) whereby Japan would provide the ACA (Atacama Compact Array) and three additional receiver bands for the large array, to form Enhanced ALMA. Further discussions between ALMA and NAOJ led to the signing of a high-level agreement on 14 September 2004 that makes Japan an official participant in Enhanced ALMA, to be known as the Atacama Large Millimeter/submillimeter Array. A groundbreaking ceremony was held on November 6, 2003 and the ALMA logo was unveiled.

    During an early stage of the planning of ALMA, it was decided to employ ALMA antennas designed and constructed by known companies in North America, Europe, and Japan, rather than using one single design. This was mainly for political reasons. Although very different approaches have been chosen by the providers, each of the antenna designs appears to be able to meet ALMA’s stringent requirements. The components designed and manufactured across Europe were transported by specialist aerospace and astrospace logistics company Route To Space Alliance, 26 in total which were delivered to Antwerp for onward shipment to Chile.

    Partners

    European Southern Observatory (EU) and the European Regional Support Centre
    National Science Foundation (US) via the National Radio Astronomy Observatory (US) and the North American ALMA Science Center (US)
    National Research Council Canada [Conseil national de recherches Canada] (CA)
    National Astronomical Observatory of Japan (JP) under the National Institute of Natural Sciences (自然科学研究機構, Shizenkagaku kenkyuukikou) (JP)
    ALMA-Taiwan at the Academia Sinica Institute of Astronomy & Astrophysics [中央研究院天文及天文物理研究所](TW)
    Republic of Chile

    ALMA is a time machine!

    ALMA-In Search of our Cosmic Origins

     
  • richardmitnick 8:54 pm on May 23, 2022 Permalink | Reply
    Tags: "Planets of binary stars as possible homes for alien life", ALMA, , Bursts may influence the structure of the later planetary system., , , , , , , The binary star systems studied in this work-NGC 1333-IRAS2A-is surrounded by a disc consisting of gas and dust., , The team has complemented the observations with computer simulations reaching both backwards and forwards in time., The two stars encircle each other and at given intervals their joint gravity will affect the surrounding gas and dust disc in a way which causes huge amounts of material to fall towards the star.   

    From The Niels Bohr Institute [Niels Bohr Institutet] (DK): “Planets of binary stars as possible homes for alien life” 

    Niels Bohr Institute bloc

    From The Niels Bohr Institute [Niels Bohr Institutet] (DK)

    at

    University of Copenhagen [Københavns Universitet] [UCPH] (DK)

    23 May 2022

    Contacts:

    Jes Kristian Jørgensen
    Professor
    Astrophysics and Planetary Science
    Niels Bohr Institute
    University of Copenhagen
    jeskj@nbi.ku.dk
    +45 35 32 41 86

    Rajika L. Kuruwita
    Postdoc
    Astrophysics and Planetary Science
    Niels Bohr Institute
    University of Copenhagen
    rajika.kuruwita@nbi.ku.dk
    +45 35 32 79 98

    Maria Hornbek
    Journalist
    Faculty of Science
    University of Copenhagen
    maho@science.ku.dk
    +45 22 95 42 83

    Nearly half of Sun-size stars are binary. According to University of Copenhagen research, planetary systems around binary stars may be very different from those around single stars. This points to new targets in the search for extraterrestrial life forms.

    Since the only known planet with life, the Earth, orbits the Sun, planetary systems around stars of similar size are obvious targets for astronomers trying to locate extraterrestrial life. Nearly every second star in that category is a binary star. A new result from research at University of Copenhagen indicate that planetary systems are formed in a very different way around binary stars than around single stars such as the Sun.

    “The result is exciting since the search for extraterrestrial life will be equipped with several new, extremely powerful instruments within the coming years. This enhances the significance of understanding how planets are formed around different types of stars. Such results may pinpoint places which would be especially interesting to probe for the existence of life,” says Professor Jes Kristian Jørgensen, Niels Bohr Institute, University of Copenhagen, heading the project.

    The results from the project, which also has participation of astronomers from Taiwan and USA, are published in the distinguished journal Nature.

    Bursts shape the planetary system

    The new discovery has been made based on observations made by the ALMA telescopes in Chile of a young binary star about 1,000 lightyears from Earth.

    The binary star system, NGC 1333-IRAS2A, is surrounded by a disc consisting of gas and dust. The observations can only provide researchers with a snapshot from a point in the evolution of the binary star system. However, the team has complemented the observations with computer simulations reaching both backwards and forwards in time.

    “The observations allow us to zoom in on the stars and study how dust and gas move towards the disc. The simulations will tell us which physics are at play, and how the stars have evolved up till the snapshot we observe, and their future evolution,” explains Postdoc Rajika L. Kuruwita, Niels Bohr Institute, second author of the Nature article.

    2
    Simulation of binary star (from the scientific article by Jørgensen, Kuruwita et al.)

    Notably, the movement of gas and dust does not follow a continuous pattern. At some points in time – typically for relatively shorts periods of ten to one hundred years every thousand years – the movement becomes very strong. The binary star becomes ten to one hundred times brighter, until it returns to its regular state.

    Presumably, the cyclic pattern can be explained by the duality of the binary star. The two stars encircle each other, and at given intervals their joint gravity will affect the surrounding gas and dust disc in a way which causes huge amounts of material to fall towards the star.

    “The falling material will trigger a significant heating. The heat will make the star much brighter than usual,” says Rajika L. Kuruwita, adding:

    “These bursts will tear the gas and dust disc apart. While the disc will build up again, the bursts may still influence the structure of the later planetary system.”

    Comets carry building blocks for life.

    The observed stellar system is still too young for planets to have formed. The team hopes to obtain more observational time at ALMA, allowing to investigate the formation of planetary systems.

    Not only planets but also comets will be in focus:

    “Comets are likely to play a key role in creating possibilities for life to evolve. Comets often have a high content of ice with presence of organic molecules. It can well be imagined that the organic molecules are preserved in comets during epochs where a planet is barren, and that later comet impacts will introduce the molecules to the planet’s surface,” says Jes Kristian Jørgensen.

    Understanding the role of the bursts is important in this context:

    “The heating caused by the bursts will trigger evaporation of dust grains and the ice surrounding them. This may alter the chemical composition of the material from which planets are formed.”

    Thus, chemistry is a part of the research scope:

    “The wavelengths covered by ALMA allow us to see quite complex organic molecules, so molecules with 9-12 atoms and containing carbon. Such molecules can be building blocks for more complex molecules which are key to life as we know it. For example, amino acids which have been found in comets.”

    Powerful tools join the search for life in space

    ALMA (Atacama Large Millimeter/submillimeter Array) is not a single instrument but 66 telescopes operating in coordination. This allows for a much better resolution than could have been obtained by a single telescope.

    Very soon the new James Webb Space Telescope (JWST) will join the search for extraterrestrial life.

    Near the end of the decade, JWST will be complemented by the ELT (European Large Telescope) and the extremely powerful SKA (Square Kilometer Array) both planned to begin observing in 2027.

    The ELT will with its 39-meter mirror be the biggest optical telescope in the world and will be poised to observe the atmospheric conditions of exoplanets (planets outside the Solar System, ed.). SKA will consist of thousands of telescopes in South Africa and in Australia working in coordination and will have longer wavelengths than ALMA.

    ”The SKA will allow for observing large organic molecules directly. The James Webb Space Telescope operates in the infrared which is especially well suited for observing molecules in ice. Finally, we continue to have ALMA which is especially well suited for observing molecules in gas form. Combining the different sources will provide a wealth of exciting results,” Jes Kristian Jørgensen concludes.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings

    Stem Education Coalition

    Niels Bohr Institute Campus

    The Niels Bohr Institutet (DK) is a research institute of the Københavns Universitet [UCPH] (DK). The research of the institute spans astronomy, geophysics, nanotechnology, particle physics, quantum mechanics and biophysics.

    The Institute was founded in 1921, as the Institute for Theoretical Physics of the Københavns Universitet [UCPH] (DK), by the Danish theoretical physicist Niels Bohr, who had been on the staff of the University of Copenhagen since 1914, and who had been lobbying for its creation since his appointment as professor in 1916. On the 80th anniversary of Niels Bohr’s birth – October 7, 1965 – the Institute officially became The Niels Bohr Institutet (DK). Much of its original funding came from the charitable foundation of the Carlsberg brewery, and later from the Rockefeller Foundation.

    During the 1920s, and 1930s, the Institute was the centre of the developing disciplines of atomic physics and quantum physics. Physicists from across Europe (and sometimes further abroad) often visited the Institute to confer with Bohr on new theories and discoveries. The Copenhagen interpretation of quantum mechanics is named after work done at the Institute during this time.

    On January 1, 1993 the institute was fused with the Astronomic Observatory, the Ørsted Laboratory and the Geophysical Institute. The new resulting institute retained the name Niels Bohr Institutet (DK).

    Københavns Universitet (UCPH) (DK) is the oldest university and research institution in Denmark. Founded in 1479 as a studium generale, it is the second oldest institution for higher education in Scandinavia after Uppsala University (1477). The university has 23,473 undergraduate students, 17,398 postgraduate students, 2,968 doctoral students and over 9,000 employees. The university has four campuses located in and around Copenhagen, with the headquarters located in central Copenhagen. Most courses are taught in Danish; however, many courses are also offered in English and a few in German. The university has several thousands of foreign students, about half of whom come from Nordic countries.

    The university is a member of the International Alliance of Research Universities (IARU), along with University of Cambridge (UK), Yale University , The Australian National University (AU), and University of California-Berkeley , amongst others. The 2016 Academic Ranking of World Universities ranks the University of Copenhagen as the best university in Scandinavia and 30th in the world, the 2016-2017 Times Higher Education World University Rankings as 120th in the world, and the 2016-2017 QS World University Rankings as 68th in the world. The university has had 9 alumni become Nobel laureates and has produced one Turing Award recipient.

     
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