Recent Updates Page 2 Toggle Comment Threads | Keyboard Shortcuts

  • richardmitnick 3:41 pm on January 22, 2018 Permalink | Reply
    Tags: , , , , , , , ,   

    From CfA: “A New Bound on Axions” 

    Harvard Smithsonian Center for Astrophysics


    Center For Astrophysics

    January 19, 2018

    1
    A composite image of M87 in the X-ray from Chandra (blue) and in radio emission from the Very Large Array (red-orange). Astronomers used the X-ray emission from M87 to constrain the properties of axions, putative particles suggested as dark matter candidates. X-ray NASA/CXC/KIPAC/N. Werner, E. Million et al.; Radio NRAO/AUI/NSF/F. Owen.

    NASA/Chandra Telescope

    NRAO/Karl V Jansky VLA, on the Plains of San Agustin fifty miles west of Socorro, NM, USA, at an elevation of 6970 ft (2124 m)

    An axion is a hypothetical elementary particle whose existence was postulated in order to explain why certain subatomic reactions appear to violate basic symmetry constraints, in particular symmetry in time. The 1980 Nobel Prize in Physics went for the discovery of time-asymmetric reactions. Meanwhile, during the following decades, astronomers studying the motions of galaxies and the character of the cosmic microwave background [CMB] radiation came to realize that most of the matter in the universe was not visible.

    CMB per ESA/Planck

    Cosmic Background Radiation per Planck

    ESA/Planck

    It was dubbed dark matter, and today’s best measurements find that about 84% of matter in the cosmos is dark. This component is dark not only because it does not emit light — it is not composed of atoms or their usual constituents, like electrons and protons, and its nature is mysterious. Axions have been suggested as one possible solution. Particle physicists, however, have so far not been able to detect directly axions, leaving their existence in doubt and reinvigorating the puzzles they were supposed to resolve.

    CfA astronomer Paul Nulsen and his colleagues used a novel method to investigate the nature of axions. Quantum mechanics constrain axions, if they exist, to interact with light in the presence of a magnetic field. As they propagate along a strong field, axions and photons should transmute from one to the other other in an oscillatory manner. Because the strength of any possible effect depends in part on the energy of the photons, the astronomers used the Chandra X-ray Observatory to monitor bright X-ray emission from galaxies. They observed X-rays from the nucleus of the galaxy Messier 87, which is known to have strong magnetic fields, and which (at a distance of only fifty-three million light-years) is close enough to enable precise measurements of variations in the X-ray flux. Moreover, Me3ssier 87 lies in a cluster of galaxies, the Virgo cluster, which should insure the magnetic fields extend over very large scales and also facilitate the interpretation. Not least, Messier 87 has been carefully studied for decades and its properties are relatively well known.

    The search did not find the signature of axions. It does, however, set an important new limit on the strength of the coupling between axions and photons, and is able to rule out a substantial fraction of the possible future experiments that might be undertaken to detect axions. The scientists note that their research highlights the power of X-ray astronomy to probe some basic issues in particle physics, and point to complementary research activities that can be undertaken on other bright X-ray emitting galaxies.

    Science paper:
    A New Bound on Axion-Like Particles, Journal of Cosmology and Astroparticle Physics.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    The 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 (SAO) is a bureau of the Smithsonian Institution, founded in 1890. The Harvard College Observatory (HCO), 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.

    Advertisements
     
  • richardmitnick 2:58 pm on January 22, 2018 Permalink | Reply
    Tags: "Cosmic messenger" particles, , , , , , , KM3NeT neutrino telescope, , , , , ,   

    From Penn State: “Three types of extreme-energy space particles may have unified origin” 

    Penn State Bloc

    Pennsylvania State University

    22 January 2018
    Kohta Murase
    murase@psu.edu
    (+1) 814-863-9594

    Barbara Kennedy (PIO):
    bkk1@psu.edu,
    (+1) 814-863-4682

    [ Barbara K. Kennedy ]

    1
    This image illustrates the “multi-messenger” emission from a gigantic reservoir of cosmic rays that are accelerated by powerful jets from a supermassive black hole. Credit: Kanoko Horio.

    One of the biggest mysteries in astroparticle physics has been the origins of ultrahigh-energy cosmic rays, very high-energy neutrinos, and high-energy gamma rays. Now, a new theoretical model reveals that they all could be shot out into space after cosmic rays are accelerated by powerful jets from supermassive black holes and they travel inside clusters and groups of galaxies. It also shows that these space particles could travel inside clusters and groups of galaxies.

    The model explains the natural origins of all three types of “cosmic messenger” particles simultaneously, and is the first astrophysical model of its kind based on detailed numerical computations. A scientific paper that describes this model, produced by Penn State and University of Maryland scientists, will be published as an Advance Online Publication on the website of the journal Nature Physics on January 22, 2018.

    “Our model shows a way to understand why these three types of cosmic messenger particles have a surprisingly similar amount of power input into the universe, despite the fact that they are observed by space-based and ground-based detectors over ten orders of magnitude in individual particle energy,” said Kohta Murase, assistant professor of physics and astronomy and astrophysics at Penn State. “The fact that the measured intensities of very high-energy neutrinos, ultrahigh-energy cosmic rays, and high-energy gamma rays are roughly comparable tempted us to wonder if these extremely energetic particles have some physical connections. The new model suggests that very high-energy neutrinos and high-energy gamma rays are naturally produced via particle collisions as daughter particles of cosmic rays, and thus can inherit the comparable energy budget of their parent particles. It demonstrates that the similar energetics of the three cosmic messengers may not be a mere coincidence.”

    Ultrahigh-energy cosmic rays are the most energetic particles in the universe — each of them carries an energy that is too high to be produced even by the Large Hadron Collider, the most powerful particle accelerator in the world. Neutrinos are mysterious and ghostly particles that hardly ever interact with matter. Very high-energy neutrinos, with energy more than one million mega-electronvolts, have been detected in the IceCube neutrino observatory in Antarctica.

    U Wisconsin IceCube neutrino observatory

    U Wisconsin IceCube experiment at the South Pole



    U Wisconsin ICECUBE neutrino detector at the South Pole


    IceCube Gen-2 DeepCore PINGU


    IceCube reveals interesting high-energy neutrino events

    Gamma rays have the highest-known electromagnetic energy — those with energies more than a billion times higher than a photon of visible light have been observed by the Fermi Gamma-ray Space Telescope and other ground-based observatories.

    NASA/Fermi LAT


    NASA/Fermi Gamma Ray Space Telescope

    “Combining all information on these three types of cosmic messengers is complementary and relevant, and such a multi-messenger approach has become extremely powerful in the recent years,” Murase said.

    Murase and the first author of this new paper, Ke Fang, a postdoctoral associate at the University of Maryland, attempt to explain the latest multi-messenger data from very high-energy neutrinos, ultrahigh-energy cosmic rays, and high-energy gamma rays, based on a single but realistic astrophysical setup. They found that the multi-messenger data can be explained well by using numerical simulations to analyze the fate of these charged particles.

    “In our model, cosmic rays accelerated by powerful jets of active galactic nuclei escape through the radio lobes that are often found at the end of the jets,” Fang said. “Then we compute the cosmic-ray propagation and interaction inside galaxy clusters and groups in the presence of their environmental magnetic field. We further simulate the cosmic-ray propagation and interaction in the intergalactic magnetic fields between the source and the Earth. Finally we integrate the contributions from all sources in the universe.”

    The leading suspects in the half-century old mystery of the origin of the highest-energy cosmic particles in the universe were in galaxies called “active galactic nuclei,” which have a super-radiating core region around the central supermassive black hole. Some active galactic nuclei are accompanied by powerful relativistic jets. High-energy cosmic particles that are generated by the jets or their environments are shot out into space almost as fast as the speed of light.

    “Our work demonstrates that the ultrahigh-energy cosmic rays escaping from active galactic nuclei and their environments such as galaxy clusters and groups can explain the ultrahigh-energy cosmic-ray spectrum and composition. It also can account for some of the unexplained phenomena discovered by ground-based experiments,” Fang said. “Simultaneously, the very high-energy neutrino spectrum above one hundred million mega-electronvolts can be explained by particle collisions between cosmic rays and the gas in galaxy clusters and groups. Also, the associated gamma-ray emission coming from the galaxy clusters and intergalactic space matches the unexplained part of the diffuse high-energy gamma-ray background that is not associated with one particular type of active galactic nucleus.”

    “This model paves a way to further attempts to establish a grand-unified model of how all three of these cosmic messengers are physically connected to each other by the same class of astrophysical sources and the common mechanisms of high-energy neutrino and gamma-ray production,” Murase said. “However, there also are other possibilities, and several new mysteries need to be explained, including the neutrino data in the ten-million mega-electronvolt range recorded by the IceCube neutrino observatory in Antarctica. Therefore, further investigations based on multi-messenger approaches — combining theory with all three messenger data — are crucial to test our model.”

    The new model is expected to motivate studies of galaxy clusters and groups, as well as the development of other unified models of high-energy cosmic particles. It is expected to be tested rigorously when observations begin to be made with next-generation neutrino detectors such as IceCube-Gen2 and KM3Net, and the next-generation gamma-ray telescope, Cherenkov Telescope Array.

    Artist’s expression of the KM3NeT neutrino telescope

    HESS Cherenkov Telescope Array, located on the Cranz family farm, Göllschau, in Namibia, near the Gamsberg

    “The golden era of multi-messenger particle astrophysics started very recently,” Murase said. “Now, all information we can learn from all different types of cosmic messengers is important for revealing new knowledge about the physics of extreme-energy cosmic particles and a deeper understanding about our universe.”

    The research was partially supported by the National Science Foundation (grant No. PHY-1620777) and the Alfred P. Sloan Foundation.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    Penn State Campus

    WHAT WE DO BEST

    We teach students that the real measure of success is what you do to improve the lives of others, and they learn to be hard-working leaders with a global perspective. We conduct research to improve lives. We add millions to the economy through projects in our state and beyond. We help communities by sharing our faculty expertise and research.

    Penn State lives close by no matter where you are. Our campuses are located from one side of Pennsylvania to the other. Through Penn State World Campus, students can take courses and work toward degrees online from anywhere on the globe that has Internet service.

    We support students in many ways, including advising and counseling services for school and life; diversity and inclusion services; social media sites; safety services; and emergency assistance.

    Our network of more than a half-million alumni is accessible to students when they want advice and to learn about job networking and mentor opportunities as well as what to expect in the future. Through our alumni, Penn State lives all over the world.

    The best part of Penn State is our people. Our students, faculty, staff, alumni, and friends in communities near our campuses and across the globe are dedicated to education and fostering a diverse and inclusive environment.

     
  • richardmitnick 2:14 pm on January 22, 2018 Permalink | Reply
    Tags: , , , CoRoT-2b, , , McGill University   

    From McGill: “A ‘hot Jupiter’ with unusual winds” 

    McGill University

    McGill University

    Contact Information
    Contact:
    Chris Chipello
    Media Relations Office
    christopher.chipello@mcgill.ca
    Office Phone:
    O: 514-398-4201
    C:514-717-4201

    Secondary Contact Information
    Nicolas Cowan
    McGill University/ McGill Space Institute
    nicolas.cowan@mcgill.ca

    Puzzling finding raises new questions about atmospheric physics of giant planets.

    1
    Artist’s concept shows the gaseous exoplanet CoRoT-2b with a westward hot spot in orbit around its host star.
    CREDIT: NASA/JPL-Caltech/T. Pyle (IPAC).

    The hottest point on a gaseous planet near a distant star isn’t where astrophysicists expected it to be – a discovery that challenges scientists’ understanding of the many planets of this type found in solar systems outside our own.

    Unlike our familiar planet Jupiter, so-called hot Jupiters circle astonishingly close to their host star — so close that it typically takes fewer than three days to complete an orbit. And one hemisphere of these planets always faces its host star, while the other faces permanently out into the dark.

    Not surprisingly, the “day” side of the planets gets vastly hotter than the night side, and the hottest point of all tends to be the spot closest to the star. Astrophysicists theorize and observe that these planets also experience strong winds blowing eastward near their equators, which can sometimes displace the hot spot toward the east.

    In the mysterious case of exoplanet CoRoT-2b, however, the hot spot turns out to lie in the opposite direction: west of center. A research team led by astronomers at McGill University’s McGill Space Institute (MSI) and the Institute for research on exoplanets (iREx) in Montreal made the discovery using NASA’s Spitzer Space Telescope.

    NASA/Spitzer Infrared Telescope

    Their findings are reported Jan. 22 in the journal Nature Astronomy.

    Wrong-way wind

    “We’ve previously studied nine other hot Jupiter, giant planets orbiting super close to their star. In every case, they have had winds blowing to the east, as theory would predict,” says McGill astronomer Nicolas Cowan, a co-author on the study and researcher at MSI and iREx. “But now, nature has thrown us a curveball. On this planet, the wind blows the wrong way. Since it’s often the exceptions that prove the rule, we are hoping that studying this planet will help us understand what makes hot Jupiters tick.”

    CoRoT-2b, discovered a decade ago by a French-led space observatory mission, is 930 light years from Earth. While many other hot Jupiters have been detected in recent years, CoRoT-2b has continued to intrigue astronomers because of two factors: its inflated size and the puzzling spectrum of light emissions from its surface.

    “Both of these factors suggest there is something unusual happening in the atmosphere of this hot Jupiter,” says Lisa Dang, a McGill PhD student and lead author of the new study. By using Spitzer’s Infrared Array Camera to observe the planet while it completed an orbit around its host star, the researchers were able to map the planet’s surface brightness for the first time, revealing the westward hot spot.

    New questions

    The researchers offer three possible explanations for the unexpected discovery – each of which raises new questions:

    The planet could be spinning so slowly that one rotation takes longer than a full orbit of its star; this could create winds blowing toward the west rather than the east – but it would also undercut theories about planet-star gravitational interaction in such tight orbits.

    The planet’s atmosphere could be interacting with the planet’s magnetic field to modify its wind pattern; this could provide a rare opportunity to study an exoplanet’s magnetic field.

    Large clouds covering the eastern side of the planet could make it appear darker than it would otherwise – but this would undercut current models of atmospheric circulation on such planets.

    “We’ll need better data to shed light on the questions raised by our finding,” Dang says. “Fortunately, the James Webb Space Telescope, scheduled to launch next year, should be capable of tackling this problem. Armed with a mirror that has 100 times the collecting power of Spitzer’s, it should provide us with exquisite data like never before.”

    Scientists from the University of Michigan, the California Institute of Technology, Arizona State University, New York University Abu Dhabi, the University of California, Santa Cruz, and Pennsylvania State University also contributed to the study.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    All about McGill

    With some 300 buildings, more than 38,500 students and 250,000 living alumni, and a reputation for excellence that reaches around the globe, McGill has carved out a spot among the world’s greatest universities.
    Founded in Montreal, Quebec, in 1821, McGill is a leading Canadian post-secondary institution. It has two campuses, 11 faculties, 11 professional schools, 300 programs of study and some 39,000 students, including more than 9,300 graduate students. McGill attracts students from over 150 countries around the world, its 8,200 international students making up 21 per cent of the student body.

     
  • richardmitnick 11:48 am on January 22, 2018 Permalink | Reply
    Tags: , , Geocorona, Lyman Alpha Imaging Camera U Tokyo, The PROCYON spacecraft NAOJ/ESA, Tracing the Path of Gas Atoms from Earth to the Final Frontier   

    From Eos: “Tracing the Path of Gas Atoms from Earth to the Final Frontier” 

    AGU bloc

    AGU
    Eos news bloc

    Eos

    1.22.18
    Sarah Witman

    Scientists capture the first complete image of Earth’s luminous geocorona and prove its ecliptic north–south symmetry.

    1
    An image of the geocorona, a luminous halo formed by photons released by hydrogen atoms in the outermost layer of Earth’s atmosphere. Credit: Rikkyo University.

    The outermost layer of Earth’s atmosphere, called the outer exosphere, is almost entirely made up of hydrogen. These hydrogen atoms scatter photons, producing a luminous halo called the geocorona. Observing the precise shape of the geocorona would shed light on the last phase of an important geophysical process: the escape of hydrogen atoms from Earth into interplanetary space.

    The exosphere has been observed from within—distances of less than 64,000 kilometers—extensively. But, from the outside looking in, past space missions have been able to observe the geocorona only from far greater distances. For example, Mariner 5 caught a glimpse from roughly 240,000 kilometers out, and Apollo 16 observed it from the Moon—about 380,000 kilometers away.

    In a recent study, Kameda et al. [Geophysical Research Letters] used the Lyman Alpha Imaging Camera on board the Proximate Object Close Flyby with Optical Navigation (PROCYON ) spacecraft to observe Earth’s geocorona from the greatest distance yet: more than 15 million kilometers away.

    3
    LAICA flight model (image credit: U Tokyo.)

    2
    The PROCYON spacecraft and comet 67P/Churumov-Gerasiment (Conceptual Image). Credit: NAOJ/ESA/Go Miyazaki.

    The camera was able to capture the first image of the entire geocorona, stretching more than 240,000 kilometers: 38 times the length of Earth’s radius. (In comparison, partial images captured by past observation revealed roughly 100,000 kilometers, or less than 16 times the length of Earth’s radius.)

    In addition to this comprehensive image—which proved the ecliptic north–south symmetry of the geocorona for the first time—the team used a mathematical model to determine the distribution of the geocoronal emission’s intensity. From this model, they found that the production of hot hydrogen in the magnetized plasmasphere (a layer of dense plasma surrounding Earth) is likely not the main process involved in shaping the outer exosphere, although it may still be involved somehow.

    This study is a step forward in the geophysical and space sciences and the first successful attempt since the 1970s era Apollo mission to paint a picture of the outermost reaches of Earth’s atmosphere.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    Eos is the leading source for trustworthy news and perspectives about the Earth and space sciences and their impact. Its namesake is Eos, the Greek goddess of the dawn, who represents the light shed on understanding our planet and its environment in space by the Earth and space sciences.

     
  • richardmitnick 10:53 am on January 22, 2018 Permalink | Reply
    Tags: , , , , , Marine geodesy, Megathrust zone, ,   

    From Eos: “Modeling Megathrust Zones” 

    AGU bloc

    AGU
    Eos news bloc

    Eos

    1.22.18
    Rob Govers

    A recent paper in Review of Geophysics built a unifying model to predict the surface characteristics of large earthquakes.

    1
    The Sendai coast of Japan approximately one year after the 2011 Tohoku earthquake. The harbor moorings and the quay show significant co-seismic subsidence. The dark band along the quay wall resulted from post-seismic uplift. Credit: Rob Govers.

    The past few decades have seen a number of very large earthquakes at subduction zones. Researchers now have an array of advanced technologies that provide insights into the processes of plate movement and crustal deformation. A review article recently published in Reviews of Geophysics pulled together observations from different locations worldwide to evaluate whether similar physical processes are active at different plate margins. The editors asked one of the authors to describe advances in our understanding and where additional research is still needed.

    What are “megathrust zones” and what are the main processes that occur there?

    A megathrust zone is a thin boundary layer between a tectonic plate that sinks into the Earth’s mantle and an overriding plate. The largest earthquakes and tsunamis are produced here. High friction in the shallow part of the megathrust zone effectively locks parts of the interface during decades to centuries. Ongoing plate motion slowly brings the shallow interface closer to failure, i.e., an earthquake. Other parts of the megathrust zone are mechanically weaker. They consequently attempt to creep at a rate that is required by plate tectonics, but are limited by being connected to the locked part of the interface.

    What insights have been learned from recent megathrust earthquakes at different margins?

    High magnitude earthquakes in Indonesia (2004), Chile (2010) and Japan (2011) were recorded by new networks utilizing Global Positioning System technology, which is capable of measuring ground displacements with millimeter accuracy. This complemented seismological observations of megathrust slip during these earthquakes. The crust turned out to deform significantly during and after these earthquakes. These observations indicated that slip on weak parts of the megathrust zone may be responsible, likely in combination with the more classical stress relaxation in the Earth’s mantle. In regions where megathrust earthquakes are anticipated, crustal deformation observations allowed researchers to identify parts of the megathrust zone that are currently locked. In our review article, we integrate these perspectives into a general framework for the earthquake cycle.

    How have models been used to complement observations and better understand these processes?

    Mechanical models are needed to tie the surface observations to their causative processes that take place from a few to hundreds of kilometers deep into the Earth, which is beyond what is directly accessible by drilling. Many of the published models focus on a single earthquake along a specific megathrust zone. We wondered what deep earth processes are common to these regions globally and built a unifying model to predict its surface expressions. Our model roughly reproduced the observed surface deformation, but it also became clear that some regional diversity would be required to match the data shortly after a major earthquake.

    What have been some of the recent significant scientific advances in understanding plate boundaries?

    Creep on weak parts of the megathrust zone is a very significant contributor to the surface measurements after an earthquake. Mantle relaxation is also relevant. We demonstrate that the surface deformation of these processes may give a biased impression of low friction on the megathrust zone. Creep on the megathrust zone downdip of a major earthquake may be responsible for observations that were puzzling thus far; in an overall context of convergence and compression, tension was observed in the overriding plate shortly after recent major earthquakes.

    What are some of the unresolved questions where additional research or modeling is needed?

    Marine geodesy is an exciting new field that aims to monitor deformation of the sea floor that already yielded important constraints on the deformation of the Japan megathrust. Measurements along various margins will tell whether all megathrusts are locked all the way up to the seafloor. A longstanding question is how observations on geological time scales of mountain building and deformation of the overriding plate are linked to the observations of active deformation. We think that the multi-earthquake cycle model that we present in this review article is a first step towards that goal.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    Eos is the leading source for trustworthy news and perspectives about the Earth and space sciences and their impact. Its namesake is Eos, the Greek goddess of the dawn, who represents the light shed on understanding our planet and its environment in space by the Earth and space sciences.

     
  • richardmitnick 9:57 am on January 22, 2018 Permalink | Reply
    Tags: , , , , Henrietta Swan Leavitt, Mapping the cosmos with Cepheid stars,   

    From astronomy.com: “Mapping the cosmos with Cepheid stars” 

    Astronomy magazine

    astronomy.com

    January 19, 2018
    Alison Klesman

    A young astronomer improves our ability to use a well-established law to measure distance.

    1
    RS Puppis is a bright Cepheid star – a star that pulsates regularly, changing its size and its brightness over time.
    NASA, ESA, and the Hubble Heritage Team (STScI/AURA)-Hubble/Europe Collaboration; Acknowledgment: H. Bond (STScI and Penn State University)

    Cepheid variable stars are a vital rung on the “ladder” astronomers use to determine the distance to astronomical objects. These pulsating stars, which change in brightness as they also change in physical size over time, allowed Edwin Hubble to measure the distance to the Andromeda Galaxy and determine that our Milky Way was one of what we now know are trillions of “island universes” — galaxies — scattered throughout the larger, expanding universe.

    These stars have been used as distance indicators since the early 1900s, thanks to the hard work of Henrietta Leavitt.

    3
    Henrietta Swan Leavitt, Born July 4, 1868, Died December 12, 1921; and Kate Hartman today

    And today, a young astronomer is using the Sloan Digital Sky Survey’s Apache Point Galactic Evolution Experiment (APOGEE) to make more precise measurements of Cepheid variables than ever before.

    SDSS APOGEE spectrograph

    SDSS Telescope at Apache Point Observatory, near Sunspot NM, USA, Altitude 2,788 meters (9,147 ft)

    Her project, featured in a press conference during last week’s 231st Meeting of the American Astronomical Society, showed that astronomers are still striving to understand the intricacies of these stars — and how they are closer than ever before to the final piece of the puzzle.

    Why Cepheid variables are special

    Kate Hartman, an undergraduate from Pomona College working with Rachael Beaton, the NASA Hubble and Carnegie-Princeton Postdoctoral Fellow at Princeton University, was tasked with using APOGEE data to determine the amount of elements present in each Cepheid star measured. Though it may sound simple, this type of measurement is vital to ensure astronomers’ calibration of the period-luminosity relationship for Cepheid variables — called the Leavitt Law — is correct. Problems with that calibration would affect distances measured using the law, which would increase uncertainties in other types of distance measurements, as well.

    2
    A light curve showing Delta Cephei’s brightness over time. Delta Cephei is the prototype Cepheid variable star, after which the class is named.
    ThomasK Vbg (Wikipedia)

    The Leavitt Law works like this: Cepheid variables are giant stars that pulsate — physically — over the course of hours or days. As Beaton explained in a press release, “over a pulsation cycle of a Cepheid variable, the star’s properties change. Its temperature, surface gravity, and atmospheric properties can vary greatly over a fairly short time.” These stars demonstrate a clear period-luminosity relationship — a correlation between the period over which a star varies and its intrinsic brightness — that means once an astronomer has measured a Cepheid’s light curve (the variation in its light over time), they immediately know the brightness of the star. Knowing the intrinsic brightness of the star — rather than simply how bright the star appears — allows the astronomer to calculate its distance, because objects get dimmer with distance via a simple and universal law.

    This is why only certain types of stars can be used as distance indicators — without the ability to know for certain how bright a star or other object actually is, astronomers cannot use it to measure distance.

    APOGEE’s Cepheid catalog

    So then the question arises: Do variables with slightly different chemical compositions or in different chemical environments have different period-luminosity relationships? Or is the single Leavitt Law capable of letting astronomers view any Cepheid variable, anywhere, and measuring its distance in a more straightforward way? And, additionally: Are surveys like APOGEE capable of producing reliable information, such as composition, about these stars, when a single image could catch the star at any random time during its pulsation period?

    Hartman and Beaton wanted to find out. APOGEE was perfect for this job, because although it’s “optimized to study the cool, old giant-type stars found all across our galaxy,” said Beaton, “Cepheid variables … are similar in temperature, so they are well suited for APOGEE.”

    Thus, APOGEE not only provides a large catalog of Cepheids, it also provides a tool to measure their properties in the same way that other (older) stars are measured. This type of consistency lets astronomers study both young and old parts of the galaxy to better trace its evolution.

    4
    The Cepheid variable star in the Andromeda Galaxy that allowed Edwin Hubble to measure the distance to our neighboring galaxy. NASA/ESA/Hubble Heritage Team

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

     
  • richardmitnick 9:14 am on January 22, 2018 Permalink | Reply
    Tags: , , Cambridge Rindge and Latin School (CRLS), , Harvard Life Sciences Outreach Program,   

    From Harvard Gazette “Learning to understand their own DNA” 

    Harvard University
    Harvard University


    Harvard Gazette

    January 19, 2018
    Deborah Blackwell

    1
    Cambridge Rindge and Latin student Hannah Thomsen isolates her DNA for sequencing during an Amgen biotech lab inside the Science Center. Kris Snibbe/Harvard Staff Photographer.

    Harvard opens its labs to help local high school students decode biotech

    On the fourth floor of Harvard’s Science Center, high school biology students from Cambridge Rindge and Latin School (CRLS) put on safety goggles and gloves, and step up to lab tables conveniently set up with pipettes, centrifuges, and other implements.

    Then they get to work isolating their own DNA.

    “This is real-life science, the stuff that people who work in biotech are actually doing in their labs, and the fact that kids get to do this at the high school level is amazing,” said Janira Arocho, a biology teacher at CRLS. “I didn’t get to do this type of stuff until I was in college.”

    Teaching younger students the tools of modern science is the goal of the Amgen Biotech Experience (ABE,) a STEM (science, technology, engineering, and mathematics) program that opens the field of biotechnology to high schoolers and their teachers, while at the same time teaching them how to approach science as critical thinkers and innovators — and a lot about who they are.

    “It’s normally really, really challenging to give them a good sense of what happens just by lecturing about it,” said Tara Bennett Bristow, site director of the Massachusetts ABE. “The ABE program is not only helping to increase their scientific literacy in biotechnology, it’s exposing them in a hands-on fashion, which generates enthusiasm.”

    In its sixth year in Massachusetts, the local branch of the program is a partnership between the Harvard and the Amgen Foundation. A foundation grant through the University’s Life Sciences Outreach Program provides the kits of materials and equipment for students to do labs that mirror the process of therapeutic research and development, and Massachusetts teachers participating in the program complete summer training workshops at Harvard.

    Arocho, who has participated in the program for several years, said with the training, “I was able to learn everything my students would be doing ahead of time, as opposed to learning along with them in my own classroom.”

    More than 80,000 students around the world — 6,000 of them from Massachusetts high schools, along with 100 of their teachers — participated in ABE last year. At Harvard, which in July received another three-year grant to continue ABE programing, about 500 CRLS students are able to use the undergraduate biology teaching laboratories, where their own teacher leads the lab and graduate students and postdoctoral fellows are on site for assistance.

    2
    CRLS students Hannah Thomsen (from left) and Elizabeth Lucas-Foley work with their Biology teacher Janira Arocho, GSAS student Alyson Ramirez, and CRLS students Peter Fulweiler and Kerri Sands. Kris Snibbe/Harvard Staff Photographer.

    n one lab in December, the CRLS students isolated their own DNA (their results were sent out for sequencing, and reports returned to them several days later for analysis). In another, the students produced a red fluorescent protein — used in the field for in vivo imaging — with common biotech tools.

    Alia Qatarneh, the site coordinator of the ABE program at Harvard, leads teacher ABE workshops, training, and student labs. Qatarneh said she is particularly excited that the program was just implemented at her alma mater, Boston Latin School, where she was able to teach an ABE lab to four advanced placement biology classes last fall.

    “It was amazing to go back to Boston Latin and think of my own experience as a high school student. I was so into science and loved hands-on things, but didn’t take AP biology because I was scared,” she said. “If I were a high school student and I had a chance to hold pipettes, to change the genetic makeup of bacteria to make it glow in the dark, how cool would that be?”

    An assessment by the nonprofit research firm WestEd found that the ABE program substantially adds to students’ knowledge of biotechnology, and increases their interest and confidence in their scientific abilities. The program is open and for free participating high school biology students, including those with learning disabilities, and even those without an interest in science.

    “Students may say, ‘Wow biotech, I didn’t know that this field existed. I thought that if I liked science I had to be a doctor, and now I have this whole different path in front of me,’” Qatarneh said.

    Arocho said her students love going to Harvard, seeing what the labs look like, and doing their work there. “Alia always starts by telling them that this is the exact same lab that the Harvard freshman are doing, and the exact same place, so they do get excited about that,” she said.

    CRLS junior Peter Fulweiler, one of Arocho’s students, said the best part is taking what he learned in the classroom and putting it all together in the lab.

    “I love the hands-on part of this. It’s really interesting, because it’s not like we are reading instructions; we are making an attempt to actually understand what we are learning by doing it,” he said. “The bonus is that we get to find out where we are from on our mothers’ side.”

    Science teacher Lawrence Spezzano is one of 10 instructors at Boston Latin now implementing the ABE program. He said it allows for flexibility and differentiation, and enhances learning opportunities as well as classroom logistics.

    “The program was perfect. As an AP biology teacher struggling to fit more labs and biotechnology into a time-constrained curriculum, the mapped-out process is creative and engaging to both me and my students,” Spezzano said.

    Kerri Sands, a junior at CRLS, said she has always dreamed of being a geneticist. She wants to eventually change the future of medicine, and now feels like she can.

    “I just love the science of this, the lab is like my home. I love the whole experience of everything from the micro pipetting to the centrifuging. I love it all,” she said. “This has made my passion for science even stronger.”

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    Harvard University campus
    Harvard is the oldest institution of higher education in the United States, established in 1636 by vote of the Great and General Court of the Massachusetts Bay Colony. It was named after the College’s first benefactor, the young minister John Harvard of Charlestown, who upon his death in 1638 left his library and half his estate to the institution. A statue of John Harvard stands today in front of University Hall in Harvard Yard, and is perhaps the University’s best known landmark.

    Harvard University has 12 degree-granting Schools in addition to the Radcliffe Institute for Advanced Study. The University has grown from nine students with a single master to an enrollment of more than 20,000 degree candidates including undergraduate, graduate, and professional students. There are more than 360,000 living alumni in the U.S. and over 190 other countries.

     
  • richardmitnick 8:17 am on January 22, 2018 Permalink | Reply
    Tags: , , Mounting Evidence Suggests a Remote Australian Region Was Once Part of North America,   

    From Science Alert: “Mounting Evidence Suggests a Remote Australian Region Was Once Part of North America” 

    ScienceAlert

    Science Alert

    22 JAN 2018
    MICHELLE STARR

    1
    (Janaka Dharmasena/Shutterstock)

    It really is a small world after all.

    Geologists tend to agree that, billions of years ago, the configuration of the continents was very different. How exactly they all fit together and when is a bit more of a puzzle, the pieces of which can be put together by studying rocks and fossils.

    Now researchers have found a series of rocks that show something surprising: part of Australia could have once been connected to part of Canada on the North American continent, around 1.7 billion years ago.

    Actually, the discovery that the two continents were once connected isn’t hugely surprising. Speculation about such a connection has existed since the late 1970s, when a paper proposed a connection dating back to the continent of Rodinia, around 1.13 billion years ago. However, an exact time and location for the connection has remained under debate.

    Found in Georgetown, a small town of just a few hundred people in the north east of Australia, the rocks are unlike other rocks on the Australian continent.

    Instead, they show similarities to ancient rocks found in Canada, in the exposed section of the continental crust called the Canadian Shield.

    This unexpected finding, according to researchers at Curtin University, Monash University and the Geological Survey of Queensland in Australia, reveals something about the composition of the ancient supercontinent Nuna.

    “Our research shows that about 1.7 billion years ago, Georgetown rocks were deposited into a shallow sea when the region was part of North America. Georgetown then broke away from North America and collided with the Mount Isa region of northern Australia around 100 million years later,” said Curtin PhD student and lead researcher Adam Nordsvan.

    “This was a critical part of global continental reorganisation when almost all continents on Earth assembled to form the supercontinent called Nuna.”

    The last time the continents were close to one another was the major supercontinent known as Pangea, which broke apart around 175 million years ago.

    However, before Pangea, the planet went through a number of supercontinent configurations – one of which was Nuna, also called Columbia, which existed from around 2.5 billion to 1.5 billion years ago.

    The team reached its conclusion by examining new sedimentological field data, and new and existing geochronological data from both Georgetown and Mount Isa, another remote town in north east Australia, and comparing it to rocks from Canada.

    According to the research, when Nuna started breaking up, the Georgetown area remained permanently stuck to Australia.

    This, the researchers said in their paper, challenges the current model that suggests the Georgetown region was part of the continent that would become Australia prior to 1.7 billion years ago.

    The research also found new evidence that Georgetown and Mount Isa mountain ranges were formed when the two regions collided.

    “Ongoing research by our team shows that this mountain belt, in contrast to the Himalayas, would not have been very high, suggesting the final continental assembling process that led to the formation of the supercontinent Nuna was not a hard collision like India’s recent collision with Asia,” said co-author Zheng-Xiang Li.

    “This new finding is a key step in understanding how Earth’s first supercontinent Nuna may have formed, a subject still being pursued by our multidisciplinary team here at Curtin University.”

    The research has been published in the journal Geology.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

     
  • richardmitnick 7:48 am on January 22, 2018 Permalink | Reply
    Tags: , , , , , New Study on Black Hole Magnetic Fields Has Thrown a Huge Surprise at Astronomers,   

    From Science Alert: “New Study on Black Hole Magnetic Fields Has Thrown a Huge Surprise at Astronomers” 

    ScienceAlert

    Science Alert

    22 JAN 2018
    MICHELLE STARR

    For the first time, scientists have studied the magnetic field of a black hole inside the Milky Way in multiple wavelengths – and found that it doesn’t conform to what we previously thought.

    1
    X-ray echoes during V404 Cygni’s feeding event in 2015. (Andrew Beardmore & NASA/Swift)

    NASA Neil Gehrels Swift Observatory

    According to researchers at the University of Florida and the University of Texas at San Antonio, the black hole called V404 Cygni’s magnetic field is much weaker than expected – a discovery that means we may have to rework our current models for black hole jets.

    V404 Cygni, located around 7,800 light-years away in the constellation of Cygnus, is a binary microquasar system consisting of a black hole about 9 times the mass of the Sun, and its companion star, an early red giant slightly smaller than the Sun.

    In 2015, the system flared into life, and, over the course of about a week, periodically flashed with activity as the black hole devoured material from its companion star.

    At times, it was the brightest X-ray object in the sky; but it also showed, according to NASA-Goddard’s Eleonora Troja, “exceptional variation at all wavelengths” – offering a rare opportunity to study both V404 Cygni and black hole feeding activity.

    It was this period that the team, led by Yigit Dallilar at the University of Florida, studied.

    When black holes are active, they become surrounded by a brightly glowing accretion disc, lit by the gravitational and frictional forces that heat the material as it swirls towards the black hole.

    As they consume matter, black holes expel powerful jets of plasma at near light-speed from the coronae – regions of hot, swirling gas above and below the accretion disc.

    Previous research [Astronomy] has shown that these coronae and the jets are controlled by powerful magnetic fields – and the stronger the magnetic fields close to the black hole’s event horizon, the brighter its jets.

    This is because the magnetic fields are thought to act like a synchrotron, accelerating the particles that travel through it.

    Dallilar’s team studied V404 Cygni’s 2015 feeding event across optical, infrared, X-ray and radio wavelengths, and found rapid synchrotron cooling events that allowed them to obtain a precise measurement of the magnetic field.

    Their data revealed a much weaker magnetic field than predicted by current models.

    “These models typically talk about much larger magnetic fields at the base of the jet, which many assume to be equivalent to the corona,” Dallilar told Newsweek.

    “Our results indicate that these models might be oversimplified. Specifically, there may not be a single magnetic field value for each black hole.”

    Black holes themselves don’t have magnetic poles, and therefore don’t generate magnetic fields. This means that the accretion disc corona magnetic fields are somehow generated by the space around a black hole – a process that is not well understood at this point.

    This result doesn’t mean that previous findings showing strong magnetic fields are incorrect, but it does suggest that the dynamics may be a little more complicated than previously thought.

    The team’s research did find that synchrotron processes dominated the cooling events, but could not provide data on what caused the particles to accelerate in the first place. It is, as one has come to expect from black holes, a finding that answers one question and turns up a lot more in need of further research.

    “We need to understand black holes in general,” said researcher Chris Packham of the University of Texas at San Antonio.

    “If we go back to the very earliest point in our universe, just after the big bang, there seems to have always been a strong correlation between black holes and galaxies. It seems that the birth and evolution of black holes and galaxies, our cosmic island, are intimately linked.

    “Our results are surprising and one that we’re still trying to puzzle out.”

    The research has been published in the journal Science.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

     
  • richardmitnick 7:25 am on January 22, 2018 Permalink | Reply
    Tags: , , , Great Barrier Reef - Australia, Helping put the Great Barrier Reef on the road to recovery,   

    From CSIROscope: “Helping put the Great Barrier Reef on the road to recovery” 

    CSIRO bloc

    CSIROscope

    22 January 2018
    No writer credit

    3
    2
    1

    The Great Barrier Reef.

    We often hear the same depressing story about the Great Barrier Reef: Australia’s iconic living structure is struggling to cope with a plethora of problems. Deteriorating water quality, rising water temperatures and ocean acidification, and consecutive bleaching events all have their detrimental impacts on the Reef.

    Despite these multiple large-scale and complex problems, many areas of the Great Barrier Reef still show resilience, which presents a window of opportunity to act.

    The Hon. Prime Minister Malcolm Turnbull recently announced a $60 million package of measures to address the challenges that face the Reef. The range of activities includes $6 million for the Australian Institute of Marine Science, ourselves and partners to scope and design a Reef Restoration and Adaptation Program (RRAP). This program will assess and develop existing and novel technologies to assist the recovery and repair of the Reef.

    Dr Peter Mayfield, our Executive Director for Environment, Energy And Resources, said the magnitude of challenges facing the Reef means it cannot be addressed by one organisation alone.

    “The RRAP will provide a unique opportunity to harness our collective knowledge and expertise across the entire research and science sector,” Dr Mayfield said.

    “We’re delighted be working alongside our many partner institutions to help deliver material solutions for the Reef.”

    Bringing together the best

    The nature of the environmental challenge facing the Reef demands the best scientific minds across a range of Australian universities, research institutions, park managers and charities. These include the Australian Institute of Marine Science, Great Barrier Reef Foundation, James Cook University, The University of Queensland, Queensland University of Technology, the Great Barrier Reef Marine Park Authority and researchers from many other organisations.

    We have a long history of working together with AIMS and the Great Barrier Marine Park Authority in the Great Barrier Reef World Heritage Area. The Reef Restoration and Adaptation Program takes this historical collaboration to a new level, involving many more national and international partners.

    Global solutions

    Coral reefs around the world support 25 per cent of all marine life and provide essential goods and services to an estimated one billion people. The solutions we uncover through this program could be used to help save reefs around the world.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    SKA/ASKAP radio telescope at the Murchison Radio-astronomy Observatory (MRO) in Mid West region of Western Australia

    So what can we expect these new radio projects to discover? We have no idea, but history tells us that they are almost certain to deliver some major surprises.

    Making these new discoveries may not be so simple. Gone are the days when astronomers could just notice something odd as they browse their tables and graphs.

    Nowadays, astronomers are more likely to be distilling their answers from carefully-posed queries to databases containing petabytes of data. Human brains are just not up to the job of making unexpected discoveries in these circumstances, and instead we will need to develop “learning machines” to help us discover the unexpected.

    With the right tools and careful insight, who knows what we might find.

    CSIRO campus

    CSIRO, the Commonwealth Scientific and Industrial Research Organisation, is Australia’s national science agency and one of the largest and most diverse research agencies in the world.

     
c
Compose new post
j
Next post/Next comment
k
Previous post/Previous comment
r
Reply
e
Edit
o
Show/Hide comments
t
Go to top
l
Go to login
h
Show/Hide help
shift + esc
Cancel
%d bloggers like this: