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  • richardmitnick 10:03 am on November 13, 2017 Permalink | Reply
    Tags: , , , , EarthSky, Moving shadows around a planet-forming star   

    From EarthSky: “Moving shadows around a planet-forming star” 

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    EarthSky

    November 13, 2017
    Deborah Byrd

    This star has a spiral disk of dust around it. Processes in the inner disk – winds, or swirls or clashes of pebbles – seem to be casting shadows on the outer disk.

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    Dust disk around the star HD 135344B. The star itself is removed from the picture. Image via Tomas Stolker/ astronomie.nl

    A team of mainly Dutch astronomers said on November 9, 2017 that it has observed moving shadows on a dust disk around a young star designated HD135344B. The star is 450 light-years away. It’s in a formation stage and shows striking spiral arms. On multiple days, the astronomers captured an image of this star and its dust disk. They used the SPHERE instrument on the Very Large Telescope in Chile, which can block the image of a central star in order to capture orbiting exoplanets or the details of dust disks like this one, with the goal of learning more about star formation.

    ESO SPHERE extreme adaptive optics system and coronagraphic facility on the extreme adaptive optics system and coronagraphic facility on the VLT, Cerro Paranal, Chile, with an elevation of 2,635 metres (8,645 ft) above sea level

    ESO/VLT at Cerro Paranal, with an elevation of 2,635 metres (8,645 ft) above sea level

    These astronomers believe that processes in the inner disk cast their shadows at the outer disk.

    The astronomers published their findings November 9 in the peer-reviewed The Astrophysical Journal. Their statement explained:

    “The discovery builds on an earlier publication in which the researchers made one image of the disk. By making multiple images, the astronomers clearly saw variations in the shadows. As a result, they could study the shadows in more detail …”

    The astronomers saw subtle variations of brightness in the outer dust disk. They presume this is because the gas and dust in the inner disk quickly turn around the star. The astronomers do not know yet which process causes the quick turning of the dust.”

    Astronomer Tomas Stolker is the first author of the paper about the shadows. He said the turning of the dust may be due to:

    “… winds, or swirls or clashes of pebbles.”

    The astronomers expect 1 or more large exoplanets – Jupiter-like worlds – to emerge from this dust disk eventually. Read more about this research from Astronomie.nl.

    Bottom line: For several days, astronomers imaged the young star HD 135344B and its dust disk. They saw moving shadows on the disk, which they believe is caused by a turning of the gas and dust in the star’s inner disk. Hence we learn more about the process by which stars and planets form.

    See the full article here .

    Please help promote STEM in your local schools.

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    Deborah Byrd created the EarthSky radio series in 1991 and founded EarthSky.org in 1994. Today, she serves as Editor-in-Chief of this website. She has won a galaxy of awards from the broadcasting and science communities, including having an asteroid named 3505 Byrd in her honor. A science communicator and educator since 1976, Byrd believes in science as a force for good in the world and a vital tool for the 21st century. “Being an EarthSky editor is like hosting a big global party for cool nature-lovers,” she says.

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  • richardmitnick 8:21 am on November 2, 2017 Permalink | Reply
    Tags: , , EarthSky, Twin Yellowstone super-eruptions altered global climate, Volcano science   

    From EarthSky: “Twin Yellowstone super-eruptions altered global climate” 

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    EarthSky

    November 2, 2017
    Eleanor Imster

    The Yellowstone supervolcano’s last eruption wasn’t a single event, but 2 closely-spaced eruptions that put the brakes on a natural global-warming trend, says a study.

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    The gorgeous colors of Yellowstone National Park’s Grand Prismatic hot spring are among the park’s myriad hydrothermal features created by the fact that Yellowstone is a supervolcano – the largest type of volcano on Earth. Photo via Windows into the Earth by Robert B. Smith and Lee J. Siegel

    The Yellowstone supervolcano’s last catastrophic eruption, about 630,000 years ago, was not a single event, but two powerful and closely-spaced eruptions, according to a new study. The super-eruptions were powerful enough, the researchers say, to slow a natural global warming trend that eventually led the planet out of a major ice age.

    For the study, presented at the Geological Society of American’s annual meeting in Seattle on October 25, 2017, a team of geologists from the University of California Santa Barbara (UCSB) analyzed two layers of volcanic ash discovered in seafloor sediments off the coast of Southern California. These layers of ash, sandwiched among sediments, bear the unique chemical fingerprint of Yellowstone’s most recent super eruption. and contain a remarkably detailed climate record of the violent events that formed the vast Yellowstone caldera – or cauldron-like crater – that we see today.
    UCSB geologist Jim Kennett said in a statement:

    “We discovered here that there are two ash-forming super eruptions 170 years apart, and each cooled the ocean by about three degrees Celsius.”

    Read more about the research here.

    By comparing the volcanic ash record with the climate record of single-celled marine animal fossils, it’s quite clear, Kennet said, that both of these eruptions caused separate volcanic winters, when ash and volcanic sulfur dioxide emissions reduce the amount of sunlight reaching Earth’s surface and cause temporary cooling. According to the study, the onset of the global cooling events was abrupt and coincided precisely with the timing of the supervolcanic eruptions.

    These cooling events occurred at an especially sensitive time, Kennet said, when the global climate was warming out of an ice age and easily disrupted by such events. But, Kennet added, each time, the cooling lasted longer than it should have, according to simple climate models. He said:

    “We see planetary cooling of sufficient magnitude and duration that there had to be other feedbacks involved.”

    These feedbacks might include increased sunlight-reflecting sea ice and snow cover or a change in ocean circulation that would cool the planet for a longer time.

    Bottom line: New research suggest that the Yellowstone supervolcano’s last eruption wasn’t a single event, but 2 closely-spaced eruptions that slowed a natural global-warming trend.

    See the full article here .

    Please help promote STEM in your local schools.

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    Stem Education Coalition

    Deborah Byrd created the EarthSky radio series in 1991 and founded EarthSky.org in 1994. Today, she serves as Editor-in-Chief of this website. She has won a galaxy of awards from the broadcasting and science communities, including having an asteroid named 3505 Byrd in her honor. A science communicator and educator since 1976, Byrd believes in science as a force for good in the world and a vital tool for the 21st century. “Being an EarthSky editor is like hosting a big global party for cool nature-lovers,” she says.

     
  • richardmitnick 8:51 am on September 28, 2017 Permalink | Reply
    Tags: , , , Both Type I and Type II active galaxies have central supermassive black holes, , EarthSky, New work suggests the black holes in Type I's eat faster   

    From U Maryland via EarthSky: “Black holes with ravenous appetites” 

    U Maryland bloc

    University of Maryland

    EarthSky

    September 27, 2017
    Deborah Byrd

    Both Type I and Type II active galaxies have central, supermassive black holes, which consume the galaxies from within. But new work suggests the black holes in Type I’s eat faster.

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    Artist’s concept of an active galaxy – with a supermassive black hole at its core, surrounded by a large, dark, donut-shaped cloud of gas and dust. Differences in Type I and Type II active galaxies were thought to be due to differences in the orientation of this cloud with respect to Earth. But a new study suggests otherwise. Image via NASA/JPL-Caltech.

    An international team of astronomers released results today (September 27, 2017) of a new X-ray study of active galaxies, which are those having a compact, highly luminous core in an otherwise normal-looking galaxy. The new study contradicts a decades-old, popular theory – the unified model of active galaxies – and provides a new answer to the question of why Type I active galaxies appear brighter than Type IIs. Both Type Is and Type IIs are thought to have supermassive black holes at their cores. The older unified model suggested Type Is appear brighter from Earth because they’re oriented differently. The new study suggests fundamental physical differences in the way Type Is consume matter and spit out energy. Specifically, it suggests, Type Is are more efficient eaters.

    The results will be published September 28 in the peer-reviewed journal Nature. Richard Mushotzky, a professor of astronomy at University of Maryland and a co-author of the study, said in a statement:

    “The unified model has been the prevailing wisdom for years. However, this idea does not fully explain the differences we observe in galaxies’ spectral fingerprints, and many have searched for an additional parameter that fills in the gaps.

    Our new analysis of X-ray data from NASA’s Swift Burst Alert Telescope suggests that Type I galaxies are much more efficient at emitting energy.”

    NASA/SWIFT Telescope

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    NASA’s Swift Burst Alert Telescope

    To measure the mass and growth rate of these galaxies’ active nuclei — the supermassive black holes at the galaxies’ centers — the researchers used data from 12 different ground-based telescopes spread across the globe to complement the data from the Swift satellite. Michael Koss, a research scientist at Eureka Scientific, Inc. and a co-author of the paper, said:

    “This project began in 2009, as part of my doctoral work at UMD, and has radically grown with the help of more than 40 researchers across the globe. When I started out, I spent a month of lonely nights by myself at the Kitt Peak National Observatory observing a few dozen galaxies.

    U Arizona Steward Observatory at Kitt Peak, AZ, USA

    I never dreamed we would eventually expand to such a large sample, enabling us to answer many amazing scientific questions for the first time.”

    The researchers said that – when they compared differences in the X-ray spectra between Type I and Type II galaxies – they found that, regardless of which way the galaxy faces Earth, the central black holes in Type I galaxies consume matter and emit energy much faster compared with the black holes at the center of Type II galaxies. Mushotzky said:

    “Our results suggest this has a lot to do with the amount of dust that sits close to the central black hole. Type II galaxies have a lot more dust close to the black hole, and this dust pushes against the gas as it enters the black hole.”

    The astronomers commented that, for decades, astronomers have preferentially studied Type II galaxies. That’s largely because the active nuclei of Type I galaxies are very bright, making it difficult to see the stars and gas clouds that constitute the rest of the galaxy and because, after all, the unified model had suggested that all active galaxies were fundamentally the same. Mushotzky said:

    “But now, because our results suggest that the two types of galaxies are indeed fundamentally different, it is likely that a lot of researchers will re-evaluate their data and take another look at Type I galaxies. By putting us on a path to better understand the differences between the galaxies that host Type I and Type II active nuclei, this work will help us better understand how supermassive black holes influence the evolution of their host galaxies.”

    Bottom line: New work suggests fundamental differences in Type I and Type II galaxies, contradicting a long-established theory.

    See the full article here .

    Please help promote STEM in your local schools.

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    Stem Education Coalition

    Deborah Byrd created the EarthSky radio series in 1991 and founded EarthSky.org in 1994. Today, she serves as Editor-in-Chief of this website. She has won a galaxy of awards from the broadcasting and science communities, including having an asteroid named 3505 Byrd in her honor. A science communicator and educator since 1976, Byrd believes in science as a force for good in the world and a vital tool for the 21st century. “Being an EarthSky editor is like hosting a big global party for cool nature-lovers,” she says.

    U Maryland Campus

    Driven by the pursuit of excellence, the University of Maryland has enjoyed a remarkable rise in accomplishment and reputation over the past two decades. By any measure, Maryland is now one of the nation’s preeminent public research universities and on a path to become one of the world’s best. To fulfill this promise, we must capitalize on our momentum, fully exploit our competitive advantages, and pursue ambitious goals with great discipline and entrepreneurial spirit. This promise is within reach. This strategic plan is our working agenda.

    The plan is comprehensive, bold, and action oriented. It sets forth a vision of the University as an institution unmatched in its capacity to attract talent, address the most important issues of our time, and produce the leaders of tomorrow. The plan will guide the investment of our human and material resources as we strengthen our undergraduate and graduate programs and expand research, outreach and partnerships, become a truly international center, and enhance our surrounding community.

    Our success will benefit Maryland in the near and long term, strengthen the State’s competitive capacity in a challenging and changing environment and enrich the economic, social and cultural life of the region. We will be a catalyst for progress, the State’s most valuable asset, and an indispensable contributor to the nation’s well-being. Achieving the goals of Transforming Maryland requires broad-based and sustained support from our extended community. We ask our stakeholders to join with us to make the University an institution of world-class quality with world-wide reach and unparalleled impact as it serves the people and the state of Maryland.

     
  • richardmitnick 7:29 am on September 13, 2017 Permalink | Reply
    Tags: , , , , , Does organic material in comets predate our solar system?, EarthSky,   

    From EarthSky: “Does organic material in comets predate our solar system?” 

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    EarthSky

    September 13, 2017
    Deborah Byrd

    “If cometary organic molecules were indeed produced in interstellar space—and if they played a role in the emergence of life on our planet—might they not also have seeded life on many other planets of our galaxy?”

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    Comet 67P/Churyumov-Gerasimenko as seen by ESA’s Rosetta spacecraft.

    On September 4, 2017, researchers in Paris announced the results of their study of the organic compounds – combinations of carbon, hydrogen, nitrogen, and oxygen – in comet 67P Churyumov-Gerasimenko. This is the comet studied up-close and in detail by ESA’s Rosetta spacecraft for two years, beginning in August 2014.

    ESA/Rosetta spacecraft

    The sorts of organic molecules found in this comet and others have long been proposed by scientists as possible building blocks for life on Earth. Published in late August in the peer-reviewed journal Monthly Notices of the Royal Astronomical Society, the French researchers advance the theory that this organic matter has its origin in interstellar space and predates the birth of our solar system.

    The Rosetta mission found a large amount of organic material in the nucleus of the comet, which some people simply 67P and others call Chury for Klim Ivanovich Churyumov, one of its discovers. The Rosetta mission found that organic matter made up 40% (by mass) of the nucleus of the comet. According to researchers Jean-Loup Bertaux and Rosine Lallement, not only were the organic molecules were produced in interstellar space, well before the formation of the solar system, but also other astronomers are already very familiar with the source of this matter. Their statement explained:

    “For 70 years, scientists have known that analysis of stellar spectra indicates unknown absorptions, throughout interstellar space, at specific wavelengths called the diffuse interstellar bands (DIBs). DIBs are attributed to complex organic molecules that American astrophysicist Theodore Snow believes may constitute the largest known reservoir of organic matter in the universe.

    This interstellar organic material is usually found in the same proportions. However, very dense clouds of matter like presolar nebulae are exceptions. In the middle of these nebulae, where matter is even denser, DIB absorptions plateau or even drop. This is because the organic molecules responsible for DIBs clump together there. The clumped matter absorbs less radiation than when it floated freely in space.

    Such primitive nebulae end up contracting to form a solar system like our own, with planets . . . and comets. The Rosetta mission taught us that comet nuclei form by gentle accretion of grains progressively greater in size. First, small particles stick together to form larger grains. These in turn combine to form still larger chunks, and so on, until we have a comet nucleus a few kilometers wide.

    Thus, the organic molecules that formerly populated the primitive nebulae—and that are responsible for DIBs—were probably not destroyed, but instead incorporated into the grains making up cometary nuclei. And there they have remained for 4.6 billion years. A sample-return mission would allow laboratory analysis of cometary organic material and finally reveal the identity of the mysterious interstellar matter underlying observed patterns in stellar spectra.

    If cometary organic molecules were indeed produced in interstellar space—and if they played a role in the emergence of life on our planet, as scientists believe today—might they not also have seeded life on many other planets of our galaxy?”

    Bottom line: French researchers advance the theory that the organic matter found in comets – possible building blocks for earthly life – has its origin in interstellar space and predates the birth of our solar system.

    See the full article here .

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  • richardmitnick 8:25 am on September 11, 2017 Permalink | Reply
    Tags: 2014 MU69 will soon become the only Kuiper Belt object ever to be visited by a spacecraft, , , , , EarthSky, , Pluto craft wakes from hibernation today   

    From EarthSky: “Pluto craft wakes from hibernation today” 

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    EarthSky

    September 11, 2017
    Deborah Byrd

    NASA/New Horizons spacecraft

    And last week mission scientists filed a flight plan for New Horizons’ next flyby – of the Kuiper Belt object 2014 MU69 – in early 2019. It’ll be farthest encounter yet between an earthly spacecraft and distant solar system body.

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    This image shows New Horizons’ current position along its full planned trajectory. The green segment of the line shows where New Horizons has traveled since launch; the red indicates the spacecraft’s future path. Positions of stars with magnitude 12 or brighter are shown from this perspective, which is slightly above the orbital plane of the planets. Via Johns Hopkins’ page Where is New Horizons?

    NASA’s New Horizons spacecraft – which visited Pluto in July, 2015 – was placed in hibernation on April 7, 2017. The craft is set to be awoken today (September 11, 2017). In the meantime, the science and mission operations teams have been developing detailed command loads for New Horizon’s next encounter, a nine-day flyby of the Kuiper Belt object 2014 MU69 on New Year’s Day, 2019. Among other things, the mission has now set the flight plan and the distance for closest approach, aiming to come three times closer to MU69 than it famously flew past Pluto in 2015.

    Hibernation reduced wear and tear on the spacecraft’s electronics, lowered operations costs and freed up NASA Deep Space Network tracking and communication resources for other missions. But New Horizons mission activity didn’t entirely stop during the hibernation period. While much of the craft is unpowered during hibernation, the onboard flight computer has continued to monitor system health and to broadcast a weekly beacon-status tone back to Earth. About once a month, the craft has sent home data on spacecraft health and safety. Onboard sequences sent in advance by mission controllers will eventually wake New Horizons to check out critical systems, gather new Kuiper Belt science data, and perform any necessary course corrections.

    2014 MU69 will soon become the only Kuiper Belt object ever to be visited by a spacecraft. It’ll be the farthest planetary encounter in history – some one billion miles (1.5 billion km) beyond Pluto and more than four billion miles (6.5 billion km) from Earth. If all goes as planned, New Horizons will come to within just 2,175 miles (3,500 km) of MU69 at closest approach, peering down on it from celestial north. The alternate plan, to be employed in certain contingency situations such as the discovery of debris near MU69, would take New Horizons within 6,000 miles (10,000 km)— still closer than the 7,800-mile (12,500-km) flyby distance to Pluto.

    The Johns Hopkins Applied Physics Laboratory manages the New Horizons mission for NASA’s Science Mission Directorate. Alan Stern, of the Southwest Research Institute (SwRI) is the principal investigator and leads the mission; SwRI leads the science team, payload operations, and encounter science planning. New Horizons is part of the New Frontiers Program managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama. APL designed, built and operates the New Horizons spacecraft. NASA.

    The Sleeping Spacecraft: How Hibernation Worked

    During hibernation mode, much of the New Horizons spacecraft was unpowered. The onboard flight computer monitored system health and broadcast a weekly beacon-status tone back to Earth. Onboard sequences sent in advance by mission controllers woke New Horizons two or three times each year to check out critical systems, calibrate instruments, gather some science data, rehearse Pluto-encounter activities, and perform course corrections.

    New Horizons pioneered routine cruise-flight hibernation for NASA. Not only has hibernation reduced wear and tear on the spacecraft’s electronics, it also lowered operations costs and freed up NASA Deep Space Network tracking and communication resources for other missions.

    Bottom line: The New Horizons spacecraft – famous for visiting Pluto in 2015 – will wake from a 157-day hibernation on September 11, 2017. Mission controllers have filed a flight plan for the 2019 encounter with 2014 MU69

    See the full article here .

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  • richardmitnick 9:01 am on September 4, 2017 Permalink | Reply
    Tags: A new look at ocean worlds, , , , , EarthSky, Europa and Enceladus - Ocean worlds?,   

    From EarthSky: “A new look at ocean worlds” 

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    EarthSky

    September 4, 2017
    Paul Scott Anderson

    Here’s how the James Webb Space Telescope – successor to Hubble, due to launch in 2018 – will study Jupiter’s moon Europa and Saturn’s moon Enceladus.

    NASA/ESA/CSA Webb Telescope annotated

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    This is Saturn’s moon Enceladus, as seen by the Cassini spacecraft. It’s thought to have a subsurface ocean and can be seen spewing water vapor from its interior. Photo via NASA/JPL-Caltech.

    NASA’s upcoming James Webb Space Telescope (JWST) will be used to study two of the most fascinating moons in our solar system – Europa and Enceladus, also known as ocean worlds since both have global oceans of water beneath their outer icy surfaces. The new observations will help scientists learn more about conditions on these worlds and guide the development of future robotic missions.

    Both moons are exciting targets since Europa’s surface has deposits of minerals thought to have come up from the ocean below, and Enceladus has huge plumes of water vapor erupting through fissures in the icy surface, originating from the subsurface ocean. Europa may also have plumes, which have been tentatively identified but not confirmed yet. Enceladus’ plumes also contain organic compounds of various complexities, which were sampled directly by the Cassini spacecraft multiple times.

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    A Galileo orbiter image of Europa has been added to a just-released Hubble Space Telescope image of what might be towering geysers of water erupting from near the moon’s south pole. NASA / ESA / W. Sparks / USGS Astrogeology Science Center

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    Enceladus. NASA.

    Astronomer Heidi Hammel is executive vice president of the Association of Universities for Research in Astronomy (AURA). She is spearheading the effort to study our solar system with the Webb telescope. She said:

    “We chose these two moons because of their potential to exhibit chemical signatures of astrobiological interest.”

    Astronomers will use Webb’s near-infrared camera (NIRCam) to take high-resolution images of Europa’s surface, to search for hot regions related to plumes and active geological processes. If a plume is found, they can then use Webb’s near-infrared spectrograph (NIRSpec) and mid-infrared instrument (MIRI) to analyze the plume’s composition. This video below shows possible results of using spectroscopy on Europa’s water plumes, obtainable using the Webb telescope’s NIRSpec instrument.

    NASA Webb NIRCam

    NASA Webb NIRspec

    NASA Webb MIRI

    Geronimo Villanueva, a planetary scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, is the lead scientist on the Webb telescope’s observation of Europa and Enceladus. He said:

    “Are they made of water ice? Is hot water vapor being released? What is the temperature of the active regions and the emitted water? Webb telescope’s measurements will allow us to address these questions with unprecedented accuracy and precision.”

    JWST will be able to study Enceladus’ plumes and surface in a similar manner, even though it is about 10 times smaller than Europa as seen by the telescope.

    For both moons, a focus will be to search for organic signatures such as methane, methanol, and ethane in the plumes. Evidence of life itself, like microbes, would be more difficult since some life-like processes could also have a geological explanation. Villanueva noted:

    “We only expect detections if the plumes are particularly active and if they are organic-rich.”

    JWST is the successor to the Hubble Space Telescope (HST) and will be the most powerful space-based telescope ever built. It is an international project led by NASA, along with the European Space Agency (ESA) and the Canadian Space Agency (CSA).

    Even if JWST isn’t able to find signs of life on either moon, it will be another huge step in understanding what conditions are like, both on their surfaces and below the ice in the oceans themselves, building on results from spacecraft such as Galileo and Cassini. It will help prepare the way for future, more advanced probes on the drawing boards now which may be able to answer that question of whether life has ever existed on (in) these far-off ocean worlds.

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    Diagram of an interior cross-section of the crust of Enceladus, showing how hydrothermal activity is thought to be causing the plumes of water vapor on the surface. Image via NASA-GSFC/SVS/NASA/JPL-Caltech/Southwest Research Institute.

    Bottom line: The James Webb Space Telescope will be used in part to study our own solar system, for example, Jupiter’s moon Europa and Saturn’s moon Enceladus, both considered ocean worlds.

    See the full article here .

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  • richardmitnick 12:17 pm on August 21, 2017 Permalink | Reply
    Tags: , , , , EarthSky, , ,   

    From EarthSky: “Studying sun’s atmosphere on eclipse day” 

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    EarthSky

    August 17, 2017
    EarthSky Voices

    Monday’s total solar eclipse will give scientists a rare opportunity to study the lower regions of the sun’s corona. Here’s what NASA scientists will be investigating.

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    A total solar eclipse gives scientists a rare opportunity to study the lower regions of the sun’s corona. These observations can help us understand solar activity, as well as the unexpectedly high temperatures in the corona. Image via NASA/S. Habbal, M. Druckmüller and P. Aniol.

    By Sarah Frazier, NASA’s Goddard Space Flight Center

    A total solar eclipse happens somewhere on Earth about once every 18 months. But because Earth’s surface is mostly ocean, most eclipses are visible over land for only a short time, if at all. The total solar eclipse of August 21, 2017, is different – its path stretches over land for nearly 90 minutes, giving scientists an unprecedented opportunity to make scientific measurements from the ground.

    Total solar eclipse of August 21, 2017: All you need to know

    When the moon moves in front of the sun on August 21, it will completely obscure the sun’s bright face. This happens because of a celestial coincidence – though the sun is about 400 times wider than the moon, the moon on August 21 will be about 400 times closer to us, making their apparent size in the sky almost equal. In fact, the moon will appear slightly larger than the sun to us, allowing it to totally obscure the sun for more than two and a half minutes in some locations. If they had the exact same apparent size, the total eclipse would only last for an instant.

    The eclipse will reveal the sun’s outer atmosphere, called the corona, which is otherwise too dim to see next to the bright sun. Though we study the corona from space with instruments called coronagraphs – which create artificial eclipses by using a metal disk to block out the sun’s face – there are still some lower regions of the sun’s atmosphere that are only visible during total solar eclipses. Because of a property of light called diffraction, the disk of a coronagraph must block out both the sun’s surface and a large part of the corona in order to get crisp pictures. But because the moon is so far away from Earth – about 230,000 miles away during the eclipse – diffraction isn’t an issue, and scientists are able to measure the lower corona in fine detail.

    NASA is taking advantage of the August 21, 2017, eclipse by funding 11 ground-based science investigations across the United States. Six of these focus on the sun’s corona.

    The source of space weather

    Our sun is an active star that constantly releases a flow of charged particles and magnetic fields known as the solar wind. This solar wind, along with discrete burps of solar material known as coronal mass ejections, can influence Earth’s magnetic field, send particles raining down into our atmosphere, and – when intense – impact satellites. Though we’re able to track these solar eruptions when they leave the sun, the key to predicting when they’ll happen could lie in studying their origins in the magnetic energy stored in the lower corona.

    A team led by Philip Judge of the High Altitude Observatory in Boulder, Colorado, will use new instruments to study the magnetic field structure of the corona by imaging this atmospheric layer during the eclipse. The instruments will image the corona to see fingerprints left by the magnetic field in visible and near-infrared wavelengths from a mountaintop near Casper, Wyoming. One instrument, POLARCAM, uses new technology based on the eyes of the mantis shrimp to obtain novel polarization measurements, and will serve as a proof-of-concept for use in future space missions. The research will enhance our understanding of how the sun generates space weather. Judge said:

    “We want to compare between the infrared data we’re capturing and the ultraviolet data recorded by NASA’s Solar Dynamics Observatory and JAXA/NASA’s Hinode satellite.

    NASA/SDO

    JAXA/HINODE spacecraft

    This work will confirm or refute our understanding of how light across the entire spectrum forms in the corona, perhaps helping to resolve some nagging disagreements.”

    The results from the camera will complement data from an airborne study imaging the corona in the infrared, as well as another ground-based infrared study led by Paul Bryans at the High Altitude Observatory.

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    High Altitude Observatory. Hawaii location.

    Bryans and his team will sit inside a trailer atop Casper Mountain in Wyoming, and point a specialized instrument at the eclipse. The instrument is a spectrometer, which collects light from the sun and separates each wavelength of light, measuring their intensity. This particular spectrometer, called the NCAR Airborne Interferometer, will, for the first time, survey infrared light emitted by the solar corona. Bryant said:

    “These studies are complementary. We will have the spectral information, which reveals the component wavelengths of light. And Philip Judge’s team will have the spatial resolution to tell where certain features are coming from.”

    This novel data will help scientists characterize the corona’s complex magnetic field — crucial information for understanding and eventually helping to forecast space weather events. The scientists will augment their study by analyzing their results alongside corresponding space-based observations from other instruments aboard NASA’s Solar Dynamics Observatory and the joint NASA/JAXA Hinode.

    In Madras, Oregon, a team of NASA scientists led by Nat Gopalswamy at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, will point a new, specialized polarization camera at the sun’s faint outer atmosphere, the corona, taking several-second exposures at four selected wavelengths in just over two minutes. Their images will capture data on the temperature and speed of solar material in the corona. Currently these measurements can only be obtained from Earth-based observations during a total solar eclipse.

    To study the corona at times and locations outside a total eclipse, scientists use coronagraphs, which mimic eclipses by using solid disks to block the sun’s face much the way the moon’s shadow does. Typical coronagraphs use a polarizer filter in a mechanism that turns through three angles, one after the other, for each wavelength filter. The new camera is designed to eliminate this clunky, time-consuming process, by incorporating thousands of tiny polarization filters to read light polarized in different directions simultaneously. Testing this instrument is a crucial step toward improving coronagraphs and ultimately, our understanding of the corona — the very root of the solar radiation that fills up Earth’s space environment.

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    NASA’s Solar and Heliospheric Observatory, or SOHO, constantly observes the outer regions of the sun’s corona. During the Aug. 21, 2017, eclipse, scientists will observe the lower regions of the sun’s corona to better understand the source of solar explosions called coronal mass ejections, as well as the unexpectedly high temperatures in the corona. Image via ESA/NASA/SOHO.

    ESA/NASA SOHO

    Unexplained coronal heating

    The answer to another mystery also lies in the lower corona: It is thought to hold the secrets to a longstanding question of how the solar atmosphere reaches such unexpectedly high temperatures. The sun’s corona is much hotter than its surface, which is counterintuitive, as the sun’s energy is generated by nuclear fusion at its core. Usually temperatures go down consistently as you move away from that heat source, the same way that it gets cooler as you move away from a fire – but not so in the case of the sun’s atmosphere. Scientists suspect that detailed measurements of the way particles move in the lower corona could help them uncover the mechanism that produces this enormous heating.

    Padma Yanamandra-Fisher of the Space Science Institute will lead an experiment to take images of the lower corona in polarized light. Polarized light is when all the light waves are oriented the same way, and it is produced when ordinary, unpolarized light passes through a medium – in this case, the electrons of the inner solar corona. Yanamandra-Fisher said:

    “By measuring the polarized brightness of the inner solar corona and using numerical modeling, we can extract the number of electrons along the line of sight. Essentially, we’re mapping the distribution of free electrons in the inner solar corona.”

    Mapping the inner corona in polarized light to reveal the density of elections is a critical factor in modeling coronal waves, one possible source of coronal heating. Along with unpolarized light images collected by the NASA-funded citizen science project called Citizen CATE, which will gather eclipse imagery from across the country, these polarized light measurements could help scientists address the question of the solar corona’s unusually high temperatures.

    Shadia Habbal of the University of Hawaii’s Institute for Astronomy in Honolulu will lead a team of scientists to image the sun during the total solar eclipse. The eclipse’s long path over land allows the team to image the sun from five sites across four different states, about 600 miles apart, allowing them to track short-term changes in the corona and increasing the odds of good weather.

    They will use spectrometers, which analyze the light emitted from different ionized elements in the corona. The scientists will also use unique filters to selectively image the corona in certain colors, which allows them to directly probe into the physics of the sun’s outer atmosphere.

    With this data, they can explore the composition and temperature of the corona, and measure the speed of particles flowing out from the sun. Different colors correspond to different elements — nickel, iron and argon — that have lost electrons, or been ionized, in the corona’s extreme heat, and each element ionizes at a specific temperature. By analyzing such information together, the scientists hope to better understand the processes that heat the corona.

    Amir Caspi of the Southwest Research Institute in Boulder, Colorado, and his team will use two of NASA’s WB-57F research jets take observations from twin telescopes mounted on the noses of the planes. They will ­­­­­capture the clearest images of the sun’s outer atmosphere — the corona — to date and the first-ever thermal images of Mercury, revealing how temperature varies across the planet’s surface.

    Bottom line: NASA scientists will study the sun’s atmosphere at the total solar eclipse of August 21, 2017. [Alot!!]

    See the full article here .

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  • richardmitnick 11:05 am on August 15, 2017 Permalink | Reply
    Tags: , , , , Dark Rift in the Milky Way, EarthSky   

    From EarthSky: “Dark Rift in the Milky Way” 

    1

    EarthSky

    August 14, 2017
    Bruce McClure

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    Thick dust clouds block our night-time view of the Milky Way, creating what is sometimes called the Great Rift or Dark Rift. Image via NASA.

    Have you ever looked up from a dark place on a starry August evening and noticed the dark areas in the Milky Way? For centuries, skywatchers pondered this Great Rift or Dark Rift, as it’s called, but today’s astronomers know it consists of dark, obscuring dusk in the disk of our Milky Way galaxy.

    How to see the Dark Rift. The Milky Way is easy to see if you have dark skies. It’s a shining band, stretching across the sky. If you want to see the Dark Rift, that’s easy, too, as long as you realize you aren’t looking for a bright object. You’re looking instead for dark lanes of dust, running the length of the starlit Milky Way band.

    You will be looking south from sometime in June or July (probably) through about October – in a dark sky – and, from a Northern Hemisphere location, you’ll see the Milky Way come off the southern to southwestern horizon. Notice that the Milky Way band looks milky white. The skies aren’t really black like ink between stars in the Milky Way. You will know when you see the Dark Rift because it is as if someone took a marker and colored it darker.

    2
    Photo by Manish Mamtani.

    Don’t miss the Milky Way and Great Rift rise. One of the most spectacular sights is to see the Milky Way as it rises. Around 10 p.m. in June, or earlier in July and August, step outside and look in the east to see the phenomena of the Great Rift and the rest of the Milky Way make its dramatic entrance as it rises into the night skies.

    Make sure you have your binoculars handy to scan the Milky Way. There are many interesting star forming regions, star clusters and millions of stars that will capture your attention.

    Look in the Great Rift and imagine all the stars that will eventually reveal themselves as the molecular gas dissipates. More about that below.

    Molecular dust is the reason it is dark. Stars are formed from great clouds of gas and dust in our Milky Way galaxy and other galaxies. When we look up at the starry band of the Milky Way, and see the Dark Rift, we are looking into our galaxy’s star-forming regions. The protostars (newly forming stars) are generating molecular dust that doesn’t allow light in the visual spectrum to shine through.

    However, with the advancement of telescopes that see in different light waves – such as X-rays or infrared – we now know that there’s activity in the area.

    Ancient cultures focused on the dark not the light areas. You know those paintings where if you look at the light areas you see one thing, but in the dark areas you see something else?

    The Dark Rift is a bit like that. A few ancient cultures in Central and South America saw the dark areas of the Milky Way as constellations. These dark constellations had a variety of myths associated with them. For example, one important dark constellation was Yacana the Llama. It rises above Cuzco, the ancient city of the Incas, every year in November.

    By the way, the other famous area of the sky that is obscured by molecular dust is visible from the Southern Hemisphere. It’s the famous Coalsack Nebula near the Southern Cross, also known as the constellation Crux. The Coal Sack is another region of star-forming activity in our night sky – much like the Great Rift.

    Bottom line: On a dark August night, looking edgewise into our galaxy’s disk, you’ll notice a long, dark lane dividing the bright starry band of the Milky Way. This Dark Rift is a place where new stars are forming.

    See the full article here .

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  • richardmitnick 1:25 pm on August 5, 2017 Permalink | Reply
    Tags: Albireo-Doubke (tripple) star system, , , , , EarthSky   

    From EarthSky: “Star of the week: Albireo” 

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    EarthSky

    1
    Albireo – one star blue and the other golden – as captured by EarthSky community member Tom Wildoner in July, 2015. Visit Tom’s blog, Leisurely Scientist.

    Albireo – also called Beta Cygni – isn’t the brightest star in the sky. It looks like an ordinary single star to the eye. But peer at it through a telescope, you’ll learn why stargazers love Albireo. With a telescope, you’ll easily see Albireo as a beautiful double star, with the brighter star gold and the dimmer star blue.

    How can you see Albireo as two stars? They are best viewed at 30X (“30 power” or a magnification of 30). Unless you have exceedingly powerful binoculars, mounted on a tripod, binoculars won’t show you Albireo as two stars, but any small telescope will. When you do see Albireo as two stars, notice the striking color contrast between the two.

    How can you spot Albireo in the night sky? It’s easy to find, if you can located Cygnus the Swan. Cygnus has an easy-to-recognize shape, that of a cross, and the constellation is also known as the Northern Cross. The brightest star in Cygnus, called Deneb, marks the head of the Cross or the Tail of the Swan. Albireo marks the base of the Cross or the Head of Cygnus.

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    The constellation Cygnus the Swan. The bright star Deneb is in the Tail of Cygnus, while Albireo is at the Head of the Swan. Albireo represents the Swan’s Beak or Eye. Image via Constellation of Words.

    3
    The constellation Cygnus lies within a larger star pattern known as the Summer Triangle. See the three bright stars here: Vega, Deneb and Altair? See how the pattern of the cross (Cygnus the Swan) likes inside the triangle made by those three stars? More about the Summer Triangle here.

    The two stars of Albireo constitute a true binary star system. In other words, its two stars aren’t merely a chance alignment as seen from Earth. Instead, they revolve around a common center of mass.

    These two stars lie quite far apart, however, and might take as long as 100,000 years to orbit one another. Even though these two stars appear close together in a telescope, keep in mind that you’re looking at a system that’s 430 light-years away.

    By the way, the brighter of the two stars in the Albireo system has been found with advanced telescopic techniques to be two stars as well. Thus there are at least three stars in this system.

    Bottom line: The star Albireo in the constellation Cygnus – also known as Beta Cygni – is a famous double star. A small telescope reveals that one star is blue and the other is gold.

    See the full article here .

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  • richardmitnick 1:34 pm on July 28, 2017 Permalink | Reply
    Tags: , EarthSky, Gravitational anomaly seen in lab crystal, , ,   

    From EarthSky: “Gravitational anomaly seen in lab crystal” 

    1

    EarthSky

    July 24, 2017
    Daniela Breitman

    An exotic effect in particle physics, theorized to occur in immense gravitational fields — near a black hole, or in conditions just after the Big Bang — has been seen in laboratory crystal.

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    Scientists use laboratory crystal to see how spacetime curvature affects subatomic particles known as Weyl fermions. Image by Robert Strasser, Kees Scherer, collage by Michael Buker via Nature.

    Physicist Johannes Gooth and his team from IBM Research in Zurich, Switzerland, claim to have observed an effect called an axial–gravitational anomaly in a crystal. The effect is predicted by Einstein’s General Relativity, which describes gravity as curved spacetime. The newly observed laboratory effect was thought to be observable only under conditions of immense gravity — for example, near a black hole, or shortly after the Big Bang. Yet it has been seen in a lab. The scientists published their work in the peer-reviewed journal Nature on July 20, 2017.

    What is a gravitational anomaly? A good explanation comes from co-author Karl Landsteiner at the IBM Research Blog:

    “Symmetries are the holy grail for physicists. Symmetry means that one can transform an object in a certain way that leaves it invariant. For example, a round ball can be rotated by an arbitrary angle, but always looks the same. Physicists say it is ‘symmetric under rotations.’ Once the symmetry of a physical system is identified it’s often possible to predict its dynamics.

    Sometimes however the laws of quantum mechanics destroy a symmetry that would happily exist in a world without quantum mechanics, i.e classical systems. Even to physicists this looks so strange that they named this phenomenon an ‘anomaly.’

    For most of their history, these quantum anomalies were confined to the world of elementary particle physics explored in huge accelerator laboratories such as Large Hadron Collider at CERN in Switzerland …

    But now a quantum anomaly has been observed in a lab. Nature said the result bolsters an emerging view that crystals such as these — crystals whose properties are dominated by quantum-mechanical effects – can act as experimental test-beds for physics effects that could be seen otherwise only under exotic circumstances (Big Bang, black hole, particle accelerator).

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    Co-author of the new paper Karl Landsteiner, a string theorist at the Instituto de Fisica Teorica UAM/CSIC, made this graphic to explain the gravitational anomaly. Image via http://newatlas.com/gravitational-anomaly-observed/50559/.

    In advanced science classes, at one point or another, we are taught Lavoisier’s Law. It states that nothing is being created, nothing is being lost, and that all is being transformed. This law – the law of the conservation of mass – is an underlying principle of basic science.

    However, when peek into the funky world of quantum materials through high energy physics, the law of the conservation of mass seems to break apart.

    Meanwhile, Einstein’s famous equation, E=mc^2, suggests that mass and energy are interchangeable (E, or energy, equals m, or mass, times c^2, or the speed of light squared).

    Gooth and his team used Einstein’s equation to create an analogy: a change heat (E) is the same as a change in mass (m). In other words, changing the temperature of a Weyl semimetal would be the same as generating a gravitational field.

    Lead author of the paper, Johannes Gooth, explained:

    “For the first time, we have experimentally observed this quantum anomaly on Earth which is extremely important towards our understanding of the universe.”

    3
    Co-authors of the paper (left to right): Fabian Menges, Johannes Gooth, and Bernd Gotsmann in a noise-free lab at IBM Research, Zurich. Image via <a href="https://c1.staticflickr.com/5/4206/34582536554_4fff0cdf49.jpg.

    Weyl fermions have been proposed in the 1920s by mathematician Hermann Weyl. They have been very interesting to scientists for some time, for some of their unique properties.

    This discovery is considered a spectacular one by many scientists, but not all scientists are convinced. Boris Spivak, physicist at the University of Washington in Seattle, doesn’t believe that an axial-gravitational anomaly could be observed in a Weyl semimetal. He said:

    "There are many other mechanisms which can explain their data."

    As always in science, time will tell.

    Bottom line: IBM scientists claim to have observed the effects of the axial-gravitational anomaly in a laboratory crystal.

    See the full article here .

    Please help promote STEM in your local schools.

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