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  • richardmitnick 12:34 pm on August 27, 2016 Permalink | Reply
    Tags: , Basic Research, Erika Tuttle, ,   

    From WCG: Women in STEM – “Meet a World Community Grid Team Member: Erika Tuttle” 

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    World Community Grid (WCG)

    26 Aug 2016

    1
    Erika Tuttle can be considered World Community Grid’s chief detective, since her job duties include searching for everything from website bugs to old invoices.

    Erika Tuttle began working on the World Community Grid team in 2009, but she was already very familiar with the project and many other IBM programs. Both of her parents (now retired) were longtime IBM employees who had begun working for the company in the 1960s. “IBM is what my parents talked about at the dinner table,” Erika says. “Sometimes I would go in to the office with my mother, and I thought it was the coolest place. I loved hearing about what she did at work.”

    After graduating from the University of Georgia with a degree in journalism, Erika began a career the television industry, eventually becoming a senior producer. But she continued to be interested in IBM. Her mother, longtime program coordinator Tedi Hahn, worked with World Community Grid for many years. As Tedi moved from being a full-time employee to part-time, she began training Erika to handle the program coordinator position.

    Tedi retired in 2015, and Erika became the full-time program coordinator. Every day, she dives into areas such as website testing, financial reconciliation, helping to coordinate with IBM’s legal team, managing the World Community Grid forum, and other important operations tasks.

    With a busy career and a family, spare time is limited. But she and her family enjoy boating on Lake Lanier and rooting for the Georgia Bulldogs together.

    Erika appreciates working with World Community Grid volunteers and with IBMers from around the world. “I really enjoy the international aspect of this job,” she says. “This is a great opportunity to work with people worldwide.”

    See the full article here.

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    World Community Grid (WCG) brings people together from across the globe to create the largest non-profit computing grid benefiting humanity. It does this by pooling surplus computer processing power. We believe that innovation combined with visionary scientific research and large-scale volunteerism can help make the planet smarter. Our success depends on like-minded individuals – like you.”

    WCG projects run on BOINC software from UC Berkeley.
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    BOINC is a leader in the field(s) of Distributed Computing, Grid Computing and Citizen Cyberscience.BOINC is more properly the Berkeley Open Infrastructure for Network Computing.

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    “Download and install secure, free software that captures your computer’s spare power when it is on, but idle. You will then be a World Community Grid volunteer. It’s that simple!” You can download the software at either WCG or BOINC.

    Please visit the project pages-

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  • richardmitnick 2:05 pm on August 26, 2016 Permalink | Reply
    Tags: , Basic Research, , ,   

    From JPL-Caltech: “Jupiter’s Extended Family? A Billion or More” 

    NASA JPL Banner

    JPL-Caltech

    August 26, 2016
    News Media Contact
    Preston Dyches
    Jet Propulsion Laboratory, Pasadena, Calif.
    818-354-7013
    preston.dyches@jpl.nasa.gov

    Written by Pat Brennan
    NASA Exoplanet Program

    1
    Comparing Jupiter with Jupiter-like planets that orbit other stars can teach us about those distant worlds, and reveal new insights about our own solar system’s formation and evolution. (Illustration) Credit: NASA/JPL-Caltech

    Our galaxy is home to a bewildering variety of Jupiter-like worlds: hot ones, cold ones, giant versions of our own giant, pint-sized pretenders only half as big around.

    Astronomers say that in our galaxy alone, a billion or more such Jupiter-like worlds could be orbiting stars other than our sun. And we can use them to gain a better understanding of our solar system and our galactic environment, including the prospects for finding life.

    It turns out the inverse is also true — we can turn our instruments and probes to our own backyard, and view Jupiter as if it were an exoplanet to learn more about those far-off worlds. The best-ever chance to do this is now, with Juno, a NASA probe the size of a basketball court, which arrived at Jupiter in July to begin a series of long, looping orbits around our solar system’s largest planet. Juno is expected to capture the most detailed images of the gas giant ever seen. And with a suite of science instruments, Juno will plumb the secrets beneath Jupiter’s roiling atmosphere.

    NASA/Juno
    NASA/Juno

    It will be a very long time, if ever, before scientists who study exoplanets — planets orbiting other stars — get the chance to watch an interstellar probe coast into orbit around an exo-Jupiter, dozens or hundreds of light-years away. But if they ever do, it’s a safe bet the scene will summon echoes of Juno.

    “The only way we’re going to ever be able to understand what we see in those extrasolar planets is by actually understanding our system, our Jupiter itself,” said David Ciardi, an astronomer with NASA’s Exoplanet Science Institute (NExSci) at Caltech.

    2

    Not all Jupiters are created equal

    Juno’s detailed examination of Jupiter could provide insights into the history, and future, of our solar system. The tally of confirmed exoplanets so far includes hundreds in Jupiter’s size-range, and many more that are larger or smaller.

    The so-called hot Jupiters acquired their name for a reason: They are in tight orbits around their stars that make them sizzling-hot, completing a full revolution — the planet’s entire year — in what would be a few days on Earth. And they’re charbroiled along the way.

    But why does our solar system lack a “hot Jupiter?” Or is this, perhaps, the fate awaiting our own Jupiter billions of years from now — could it gradually spiral toward the sun, or might the swollen future sun expand to engulf it?

    Not likely, Ciardi says; such planetary migrations probably occur early in the life of a solar system.

    “In order for migration to occur, there needs to be dusty material within the system,” he said. “Enough to produce drag. That phase of migration is long since over for our solar system.”

    Jupiter itself might already have migrated from farther out in the solar system, although no one really knows, he said.

    Looking back in time

    If Juno’s measurements can help settle the question, they could take us a long way toward understanding Jupiter’s influence on the formation of Earth — and, by extension, the formation of other “Earths” that might be scattered among the stars.

    “Juno is measuring water vapor in the Jovian atmosphere,” said Elisa Quintana, a research scientist at the NASA Ames Research Center in Moffett Field, California. “This allows the mission to measure the abundance of oxygen on Jupiter. Oxygen is thought to be correlated with the initial position from which Jupiter originated.”

    If Jupiter’s formation started with large chunks of ice in its present position, then it would have taken a lot of water ice to carry in the heavier elements which we find in Jupiter. But a Jupiter that formed farther out in the solar system, then migrated inward, could have formed from much colder ice, which would carry in the observed heavier elements with a smaller amount of water. If Jupiter formed more directly from the solar nebula, without ice chunks as a starter, then it should contain less water still. Measuring the water is a key step in understanding how and where Jupiter formed.

    That’s how Juno’s microwave radiometer, which will measure water vapor, could reveal Jupiter’s ancient history.

    “If Juno detects a high abundance of oxygen, it could suggest that the planet formed farther out,” Quintana said.

    A probe dropped into Jupiter by NASA’s Galileo spacecraft in 1995 found high winds and turbulence, but the expected water seemed to be absent. Scientists think Galileo’s one-shot probe just happened to drop into a dry area of the atmosphere, but Juno will survey the entire planet from orbit.

    NASA Galileo
    NASA/Galileo

    The chaotic early years

    Where Jupiter formed, and when, also could answer questions about the solar system’s “giant impact phase,” a time of crashes and collisions among early planet-forming bodies that eventually led to the solar system we have today.

    Our solar system was extremely accident-prone in its early history — perhaps not quite like billiard balls caroming around, but with plenty of pileups and fender-benders.

    “It definitely was a violent time,” Quintana said. “There were collisions going on for tens of millions of years. For example, the idea of how the moon formed is that a proto-Earth and another body collided; the disk of debris from this collision formed the moon.

    Theia collision with Earth
    Theia collision with Earth. William K. Hartmann

    And some people think Mercury, because it has such a huge iron core, was hit by something big that stripped off its mantle; it was left with a large core in proportion to its size.”

    Part of Quintana’s research involves computer modeling of the formation of planets and solar systems. Teasing out Jupiter’s structure and composition could greatly enhance such models, she said. Quintana already has modeled our solar system’s formation, with Jupiter and without, yielding some surprising findings.

    “For a long time, people thought Jupiter was essential to habitability because it might have shielded Earth from the constant influx of impacts [during the solar system’s early days] which could have been damaging to habitability,” she said. “What we’ve found in our simulations is that it’s almost the opposite. When you add Jupiter, the accretion times are faster and the impacts onto Earth are far more energetic. Planets formed within about 100 million years; the solar system was done growing by that point,” Quintana said.

    “If you take Jupiter out, you still form Earth, but on timescales of billions of years rather than hundreds of millions. Earth still receives giant impacts, but they’re less frequent and have lower impact energies,” she said.

    Getting to the core

    Another critical Juno measurement that could shed new light on the dark history of planetary formation is the mission’s gravity science experiment. Changes in the frequency of radio transmissions from Juno to NASA’s Deep Space Network will help map the giant planet’s gravitational field.

    NASA Deep Space Network Canberra, Australia
    “NASA Deep Space Network Canberra, Australia, radio telescopes on watch.

    Knowing the nature of Jupiter’s core could reveal how quickly the planet formed, with implications for how Jupiter might have affected Earth’s formation.

    And the spacecraft’s magnetometers could yield more insight into the deep internal structure of Jupiter by measuring its magnetic field.

    “We don’t understand a lot about Jupiter’s magnetic field,” Ciardi said. “We think it’s produced by metallic hydrogen in the deep interior. Jupiter has an incredibly strong magnetic field, much stronger than Earth’s.”

    Mapping Jupiter’s magnetic field also might help pin down the plausibility of proposed scenarios for alien life beyond our solar system.

    Earth’s magnetic field is thought to be important to life because it acts like a protective shield, channeling potentially harmful charged particles and cosmic rays away from the surface.

    4
    Earth’s magnetic field, NASA

    “If a Jupiter-like planet orbits its star at a distance where liquid water could exist, the Jupiter-like planet itself might not have life, but it might have moons which could potentially harbor life,” he said.

    An exo-Jupiter’s intense magnetic field could protect such life forms, he said. That conjures visions of Pandora, the moon in the movie “Avatar” inhabited by 10-foot-tall humanoids who ride massive, flying predators through an exotic alien ecosystem.

    Juno’s findings will be important not only to understanding how exo-Jupiters might influence the formation of exo-Earths, or other kinds of habitable planets. They’ll also be essential to the next generation of space telescopes that will hunt for alien worlds. The Transiting Exoplanet Survey Satellite (TESS) will conduct a survey of nearby bright stars for exoplanets beginning in June 2018, or earlier.

    NASA/TESS
    NASA/TESS

    The James Webb Space Telescope, expected to launch in 2018, and WFIRST (Wide-Field Infrared Survey Telescope), with launch anticipated in the mid-2020s, will attempt to take direct images of giant planets orbiting other stars.

    NASA/ESA/CSA Webb Telescope annotated
    NASA/ESA/CSA Webb Telescope annotated

    NASA/WFIRST
    NASA/WFIRST

    “We’re going to be able to image planets and get spectra,” or light profiles from exoplanets that will reveal atmospheric gases, Ciardi said. Juno’s revelations about Jupiter will help scientists to make sense of these data from distant worlds.

    “Studying our solar system is about studying exoplanets,” he said. “And studying exoplanets is about studying our solar system. They go together.”

    To learn more about a few of the known exo-Jupiters, visit:

    https://exoplanets.nasa.gov/alien-worlds/strange-new-worlds

    See the full article here .

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    Jet Propulsion Laboratory (JPL) is a federally funded research and development center and NASA field center located in the San Gabriel Valley area of Los Angeles County, California, United States. Although the facility has a Pasadena postal address, it is actually headquartered in the city of La Cañada Flintridge [1], on the northwest border of Pasadena. JPL is managed by the nearby California Institute of Technology (Caltech) for the National Aeronautics and Space Administration. The Laboratory’s primary function is the construction and operation of robotic planetary spacecraft, though it also conducts Earth-orbit and astronomy missions. It is also responsible for operating NASA’s Deep Space Network.

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  • richardmitnick 11:59 am on August 26, 2016 Permalink | Reply
    Tags: , , Basic Research, , New Efforts to Identify Dark Matter   

    From AAS NOVA: “New Efforts to Identify Dark Matter” 

    AASNOVA

    American Astronomical Society

    26 August 2016
    Susanna Kohler

    1
    The dark matter of the universe forms the basis for the formation of galaxies. But what is this dark matter made of? [AMNH]

    Could the dark matter in our universe be “warm” instead of “cold”? Recent observations have placed new constraints on the warm dark matter model.

    What’s the Deal with Cold/Warm/Hot Dark Matter?

    2
    An example of cold dark matter: MACHOs, massive objects like black holes that are hiding in the halo of our galaxy. [Alain r]

    Nobody knows what dark matter is made of, but we have a few theories. The objects or particles that could make up dark matter fall into three broad categories — cold, warm, and hot dark matter — based on something called their “free streaming length,” or how far they moved due to random motions in the early universe.

    Neutrinos are an example of hot dark matter: very light particles with free streaming lengths much longer than the size of a typical galaxy. Cold dark matter could consist of objects like black holes or brown dwarfs, or particles like WIMPs — all of which are very heavy and therefore have free streaming lengths much shorter than the size of a galaxy.

    Warm dark matter is what’s in between: middle-mass particles with free streaming lengths roughly the size of a galaxy. There aren’t any known particles that fit this description, but there are theorized particles such as sterile neutrinos or gravitinos that do.

    3
    Cumulative mass functions at z = 6 for different values of the warm dark matter particle mass mX. The shaded boxs on the left correspond to the observed number density of faint galaxies within different confidence levels. [Menci et al. 2016]

    Smoothing Out the Universe

    The widely favored model is lambda-CDM, in which cold dark matter makes up the missing matter in our universe. This model nicely explains much of what we observe, but it still has a few problems. The biggest issue with lambda-CDM is that it predicts that there should be many more small, dwarf galaxies than we observe.

    While this could just mean that we haven’t yet managed to see all the existing, faint dwarf galaxies, we should also consider alternative models — the warm dark matter model chief among them.

    In the early universe, small density perturbations on sub-galactic scales produce dwarf galaxies in the lambda-CDM model. But in the warm dark matter model, the longer free streaming length of the dark matter particles smooth out some of those small perturbations. This results in the formation of fewer dwarf galaxies — which fits better with our current observations.

    Limits on Warm Dark Matter

    So how can we test this alternative model? The maximum number density of dark-matter halos predicted by the warm dark matter model at a given redshift depends on the mass of the candidate dark matter particle: a larger particle mass means that more halos form. We therefore can set lower limits on the mass of dark matter particles in a two-step process:

    1. Calculate the maximum number density of dark matter halos predicted by models, and
    2. Compare this to the measured abundance of the faintest galaxies at a given redshift.

    4
    Another way of looking at it: for different values of the dark matter particle mass mX, this shows the maximum number density of dark matter halos predicted at z = 6. The shaded areas represent the observed number density of faint galaxies at different confidence levels. [Menci et al. 2016]

    Recently, unprecedented new Hubble observations of ultra-faint, lensed galaxies in the Hubble Frontier Fields at z~6 have allowed for the discovery of more faint galaxies at this redshift than ever before. Now, a team of scientists led by Nicola Menci (INAF Rome) have used these observations to set a new limit on the lowest mass that candidate dark matter particles can have.

    Menci and collaborators find that these new observations constrain the particle masses to be above 2.9 keV at the 1σ confidence level. These constitute the tightest constraints on the mass of candidate warm dark matter particles derived to date, and they even allow us to rule out some production mechanisms for theorized particles.

    Extending this analysis to other clusters with deep observations will only improve the constraints, bringing us ever closer to understanding what dark matter is made of.

    Citation

    N. Menci et al 2016 ApJ 825 L1. doi:10.3847/2041-8205/825/1/L1

    See the full article here .

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  • richardmitnick 11:43 am on August 26, 2016 Permalink | Reply
    Tags: Astronomers find a brown dwarf companion to a nearby debris disk host star, , Basic Research, HR 2562,   

    From phys.org: “Astronomers find a brown dwarf companion to a nearby debris disk host star” 

    physdotorg
    phys.org

    August 26, 2016
    Tomasz Nowakowski

    1
    Collapsed datacubes showing HR 2562B in each of the four modes observed with GPI and reduced using KLIP. The K2 image is from February 2016 and demonstrates two possible solutions for the inner edge of the disk (38 and 75 AU with dashed and dotted-dashed lines respectively) assuming inclination of 78 degrees and position angle of 120 degrees. Credit: Konopacky et al., 2016.

    Astronomers have detected a brown dwarf orbiting HR 2562 – a nearby star known to host a debris disk. The newly discovered substellar companion is the first brown dwarf-mass object found to reside in the inner hole of a debris disk. The findings were presented in a paper published Aug. 23 on the arXiv pre-print server.

    HR 2562, located some 110 light years away, is an F5V star, about 30 percent more massive than the sun. It has a debris disk—a circumstellar belt of dust and planetesimals left over from planetary formation. The disk around HR 2562, spans from 38 to 75 AU away from the host star.

    In January and February 2016, a team of researchers, led by Quinn Konopacky of the University of California, San Diego, observed HR 2562 using the Gemini Planet Imager (GPI), mounted on the Gemini South Telescope in Chile. GPI is a high-contrast imaging instrument, allowing imaging and integral field spectroscopy of extrasolar planets. The observations of HR 2562 were conducted as part of the Gemini Planet Imager Exoplanet Survey (GPIES), that images young Jupiters and debris disks around nearby stars.

    However, their search for a young, Jupiter-like planet resulted in a discovery of a much more massive substellar object. The data obtained during the observations, allowed the team to confirm the existence of a brown dwarf that could have at least 15 Jupiter masses. The newly found companion is separated by about 20 AU from the host star and was designated HR 2562B.

    “We present the discovery of a brown dwarf companion to the debris disk host star HR 2562. This object, discovered with the Gemini Planet Imager, has a projected separation of 20.3±0.3 AU from the star,” the researchers wrote in the paper.

    Separation by only 20 AU means that HR 2562B lies within the inner hole of the debris disk; significantly, it is the first known brown dwarf residing inside such a gap. The scientists also noted that so far, only few substellar companions have been imaged within 100 AU from their host stars.

    While the separation of HR 2562B has been precisely estimated, its mass remains uncertain. The scientists revealed that its minimum mass is at least 15 Jupiter masses. However, the brown dwarf could be even 45 times more massive than Jupiter as well. Thus, the mean value was calculated to be 30 Jupiter masses.

    Moreover, the host star’s age also remains to be determined, as previous observations delivered conflicting results, ranging from 20 million to even 1.6 billion years. However, for the purposes of the recent study, the team adopted a nominal age range of 300 to 900 million years.

    The findings, accepted for publication in ApJ Letters, published by Konopacky and her team, could be helpful to better understand the formation process of circumstellar companions; it is widely debated whether these objects form within a circumstellar disk and reach a mass above the deuterium burning limit or via cloud fragmentation, as in binary systems with a high mass ratio.

    The researchers concluded that future studies of the HR 2562 system should focus on constraining the true mass and orbit of the companion. It could be essential to determine its possible origin, which could offer evidence of planet formation above the deuterium burning limit.

    See the full article here .

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    Phys.org™ (formerly Physorg.com) is a leading web-based science, research and technology news service which covers a full range of topics. These include physics, earth science, medicine, nanotechnology, electronics, space, biology, chemistry, computer sciences, engineering, mathematics and other sciences and technologies. Launched in 2004, Phys.org’s readership has grown steadily to include 1.75 million scientists, researchers, and engineers every month. Phys.org publishes approximately 100 quality articles every day, offering some of the most comprehensive coverage of sci-tech developments world-wide. Quancast 2009 includes Phys.org in its list of the Global Top 2,000 Websites. Phys.org community members enjoy access to many personalized features such as social networking, a personal home page set-up, RSS/XML feeds, article comments and ranking, the ability to save favorite articles, a daily newsletter, and other options.

     
  • richardmitnick 11:24 am on August 26, 2016 Permalink | Reply
    Tags: , Basic Research, , , ,   

    From Ethan Siegel: “NASA’s Revived STEREO-B Could Save Us From A Trillion Dollar Disaster” 

    From Ethan Siegel

    Aug 26, 2016

    1
    An X-class solar flare erupted from the Sun’s surface in 2012. At the time, it was the largest flare in five years. Image credit: NASA/Solar Dynamics Observatory (SDO) via Getty Images.

    Solar flares are spectacular sights from space, where giant streams of plasma are ejected from the Sun’s interior at incredibly high energies and speeds. They stream through the Solar System, usually traveling the Sun-Earth distance in three days or fewer. While this intense, ionized radiation would be dangerous to an astronaut in the depths of space, for the most part our planet’s magnetic field and atmosphere shields our bodies from any harm. The magnetic field funnels the radiation away from Earth, only enabling it to strike in a region around the poles, while the atmosphere ensures that the charged particles themselves don’t make it down to the surface. But their changing magnetic fields do, and that’s enough to induce currents in electrical wires, circuits and loops. Thankfully, now that NASA’s STEREO-A and STEREO-B spacecraft are both alive simultaneously, we’ll get the earliest warnings possible if a potential catastrophe is headed our way.

    NASA/STEREO spacecraft
    NASA/STEREO spacecraft

    You might think this is a rare event, but it’s not at all rare like a meteor striking Earth is rare. It’s not even “rare” in the sense that seeing a supernova from Earth is rare; an ultra-high-energy solar flare directed right at Earth is a question of when, not if. Imagine a beautiful, clear day. The Sun is shining, the skies are clear, and you couldn’t ask for a nicer day. All of a sudden, the Sun itself appears to brighten, just for a brief amount of time, like it released an extra burst of energy. That night, some 17 hours later, the most spectacular auroral display ever brightens the night in a way you never imagined.

    2
    Sunspots are often, but not always, portents of where a solar flare is most likely to occur. Image credit: Shahrin Ahmad (ShahGazer), Kuala Lumpur, Malaysia.

    Workers across the United States awaken at 1 a.m., because the sky is as bright as the dawn. Aurorae illuminate the skies as far south as the Caribbean, beneath the Tropic of Cancer. And long, electricity-carrying wires spark, start fires and even operate and send signals when there’s no electricity! This even includes, believe it or not, when they aren’t plugged in. This isn’t a science-fiction scenario; this is history. This is what a catastrophic Solar Storm looks like, and this actually occurred exactly as described in 1859.

    3
    A significant coronal mass ejection from the Sun that (thankfully) was not directed at Earth. Image credit: NASA / GSFC / SDO.

    NASA/SDO
    NASA/SDO

    The way this actually happens is that the Sun, rather than being this constant ball of nuclear fire in the sky, has an active surface, complete with an intricate magnetic structure, temperature variations, sunspots, and occasional flares and mass ejections. For reasons we don’t completely understand, the Sun’s activity levels ebb and peak on an 11-year timescale known as the Solar Cycle, and the transition between 2013/2014 was anticipated to have been the peak of our current cycle. We’re more likely to see larger numbers of flares, as well as stronger-than-average flares, during the peak years, but in reality they can occur at any time.

    Typically (but not always), these flares pose no danger to anything here on Earth, for a variety of reasons.

    1.) Most solar flares are not directed anywhere near the Earth. Space is a big place, and even at our relatively close distance of 93 million miles (or 150 million km) from the Sun, that’s a long way away. Even though most sunspots occur near the solar equator, more than 95% of flares and ejections, when they occur, never impact our planet at all. But there is that pesky few percent that does impact us.

    4
    A representation of how most ionized particles are diverted away from Earth by our magnetic field. Image credit: NASA.

    Magnetosphere of Earth, original bitmap from NASA. SVG rendering by Aaron Kaase
    Magnetosphere of Earth, original bitmap from NASA. SVG rendering by Aaron Kaase

    2.) Most flares are too small, too slow and sub-optimally aligned to get past the Earth’s magnetic field. Our magnetic field is awesome! Sure, it might be less than 1 G (gauss) at the surface (or 0.0001 T — for Tesla — for you mks sticklers out there), barely enough to deflect your compass needles towards the magnetic poles. But the field extends far into space, and the matter ejected in a solar flare are almost exclusively charged particles, which typically move at speeds of only a million miles an hour.

    These particles are bent by our magnetic field (as are all charged particles moving through a magnetic field) and will mostly be deflected away from the Earth. The ones that are bent into the Earth will crash into our upper atmosphere; this is the cause of nearly all auroral events.

    5
    The atmospheric effects of the aurorae, as seen from space. Image credit: NASA / ISS expedition crew 23.

    3.) Our atmosphere is sufficiently thick to prevent these charged particles from irradiating us. Even if the flare moves quickly (or at about five million miles-per-hour), is huge (containing billions of tons of matter), and is aimed directly at us, the charged particles will never make it through our atmosphere, down to the surface. In fact, they peter out to practically nothing nearly 50 km above the Earth’s surface, far higher than any mountains or even that the heights airliners reach. Unless you’re in space (for some reason) at the time, you won’t receive any more radiation than you normally would, and there is no biological risk.

    But there is one real risk, and it’s a consequence of our physical laws of electromagnetism.

    6
    The anatomy of the dangers of a solar flare. Image credit: NASA.

    A charged particle is bent as it moves through a magnetic field because of the connection between electricity and magnetism. But that same connection means that a change in electric currents — which are made by the motion of charged particles — create changing magnetic fields. And if you have a changing magnetic field either around a wire or through a loop or coil of wire, you will generate electric currents!

    So while there may not be a danger to you, there is a huge danger to electronics, ranging from automobiles to transformers to — most frighteningly of all — the entire power grid! That’s the real danger of a solar storm: an event similar to the 1859 Carrington event could cause anywhere between an estimated $1-to-$2 trillion of property damage, mostly due to electrical fires and damage to our infrastructure.

    7
    Depiction of 1859 Carrington event.Politesseo

    8
    A number of NASA satellites throughout the solar system. Image credit: NASA.

    With the space weather satellites we had up just a few years ago, we would have about a half-day’s warning to shut down our power stations and voluntarily shut off the grid in the event of such a flare. With STEREO-A and STEREO-B operating simultaneously, however, we can know as soon as the flare occurs, giving us up to three days of lead time. These events cannot be predicted in advance, and neither can their interaction with the interplanetary-and-Earth’s magnetic field, so you must never listen to fear-mongers who tell you a catastrophic solar flare is imminent; we can only be prepared to react when one is detected.

    9
    The combination of NASA’s STEREO-A (ahead) and STEREO-B (behind), combined with the solar dynamics observatory (SDO) near Earth gives us a full view of the entire photosphere of the Sun at once. Image credit: NASA.

    Ideally, we’d be able to either upgrade the grid or to simply install a sufficient amount of electrical grounding, but practically, the first option is a long-term project that no one is working on, and the second one is continuously thwarted by thievery of copper wire. Power stations and substations simply do not maintain enough grounding due to this thievery, and there’s no known antidote to that, since if death-by-electrocution isn’t enough of a deterrent, what will be?

    There’s no need to be afraid of these things, but you do need to be prepared. If an ultra-massive, fast-moving coronal mass ejection ever heads directly towards Earth, you are literally taking your life into your hands if you do not shut down and unplug all of your electronic devices — and your power companies deliberately black out your neighborhood — until the storm passes. Long-distance wires, power stations and substations and the major components of the electrical grid itself will be at the greatest risk, as they will have huge direct currents (in systems designed only to carry AC) induced in them. The smartest move for those components, quite honestly, might be to sever the wires. That’s the only surefire way we have of personally safely dealing with things now.

    But you should also keep in mind that there’s only about a 1% chance we’ll get a large, powerful Earth-directed flare in any given year, and only about a 0.2% of getting an event like we did in 1859. So be aware, be informed and know how to deal with it if it happens, but don’t lose any sleep over it! Instead, your best bet is — when applicable — to go outside and enjoy the auroral show!

    This article is dedicated to Jake Morgan, whose fascination with solar storms led him to write his first book: Sunburned. Jake recently suffered a catastrophic accident and is undergoing significant time in the ICU; you can help support his GoFundMe here.

    See the full article here .

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    “Starts With A Bang! is a blog/video blog about cosmology, physics, astronomy, and anything else I find interesting enough to write about. I am a firm believer that the highest good in life is learning, and the greatest evil is willful ignorance. The goal of everything on this site is to help inform you about our world, how we came to be here, and to understand how it all works. As I write these pages for you, I hope to not only explain to you what we know, think, and believe, but how we know it, and why we draw the conclusions we do. It is my hope that you find this interesting, informative, and accessible,” says Ethan

     
  • richardmitnick 7:40 am on August 26, 2016 Permalink | Reply
    Tags: , Basic Research, ,   

    From Sandia: Women in STEM – “Path to success: Sandia women honored for leadership, science ” Jill Hruby and Christine Coverdale 


    Sandia Lab

    August 26, 2016

    Two women at Sandia National Laboratories were recognized by professional organizations for their leadership and groundbreaking scientific research.

    The Society of Women Engineers (SWE) recently gave Sandia President and Laboratories Director Jill Hruby — the first woman to lead a national security laboratory — its 2016 Suzanne Jenniches Upward Mobility Award and gave plasma physicist Christine Coverdale its Prism Award.

    And this year Coverdale became the first woman to win the IEEE Plasma Science and Applications Committee Award in its 28-year history.

    The Suzanne Jenniches award is one of SWE’s top honors, recognizing a woman “who has succeeded in rising within her organization to a significant management position such that she is able to influence the decision-making process and has created a nurturing environment for other women in the workplace.” The Prism Award honors “a woman who has charted her own path throughout her career, providing leadership in technology fields and professional organizations along the way.”

    Coverdale’s IEEE award recognizes outstanding contributions to the field of plasma science through research, teaching and professional service to the scientific community.

    Hruby said the awards reflect on the entire lab. “Sandia has created opportunities for me and women like Christine Coverdale that allowed our careers to thrive,” she said. “This award recognizes a culture that values diversity and encourages every individual to succeed.”

    Coverdale said she is grateful for the recognition from her peers. “These awards mean a lot to me,” she said. “I have been lucky to have had many opportunities at Sandia to lead interesting and challenging projects, be mentored by highly capable people and ultimately give back and mentor students and newer staff members.”

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    Sandia President and Labs Director Jill Hruby, the first woman to lead a national security laboratory, has been a longtime mentor and advocate for women in engineering. (Photo by Randy Montoya)

    Jill Hruby: Rising to the top

    Hruby joined Sandia in 1983 at the labs’ Livermore, California, site. She worked six years in thermal and fluid sciences, solar thermal energy and nuclear weapons components then was promoted to technical manager. Over the next eight years, she led teams focused on the maturation of nuclear weapon components, analytical chemistry and materials selection for nuclear weapons systems, and materials management for advanced energy storage devices, including batteries and capacitors.

    Hruby became a senior manager and for six years was technical deputy director, leading a portfolio of programs ranging from microtechnologies to weapons components to materials processing. She moved into executive management in 2003 as director of the Materials and Engineering Sciences department at the California site. She led a team of about 200 working in hydrogen science and engineering, and nanosystem science and fabrication.

    She went on to direct the organization overseeing Sandia’s programs with the Department of Homeland Security, National Institutes of Health and numerous partners. She and her team focused on homeland work preventing and countering weapons of mass destruction, infrastructure protection and cybersecurity.

    Hruby came to Sandia New Mexico in 2010 as vice president for both the Energy, Non-Proliferation and High Consequence Security division and the International, Homeland, and Nuclear Security program management unit. She oversaw projects in nuclear nonproliferation, arms control, nuclear weapons and nuclear materials security, nuclear incident response, biological and chemical defense and security, counterterrorism and homeland security.

    Five years later, in June 2015, Hruby was tapped for the top job at Sandia, the nation’s largest national lab with more than 10,000 employees and a $2.8 billion annual budget.

    Hruby has been a longtime mentor and advocate for women in engineering. She worked with the Sandia Women’s Action Network in New Mexico and the Sandia Women’s Connection in California. She has been a role model to dozens of women at the Labs and inspired them to become leaders. And through community outreach, she has encouraged female high school and college students to consider careers in engineering.

    “I am honored to receive this award on behalf of Sandia, where I was encouraged every step of the way,” Hruby said. “It is the kind of inclusive and supportive environment where future leaders will be developed.”

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    Christine Coverdale of Sandia National Laboratories is the first woman to win the IEEE Plasma Science and Applications Committee Award in its 28-year history. (Photo by Randy Montoya)

    Christine Coverdale: Experiments in pulsed power

    Coverdale joined Sandia in 1997 and in 2011 was named a Distinguished Member of the Technical Staff. She has been involved in a broad range of experiments at the Saturn and Z pulsed power facilities centered around nuclear weapons certification and other national security projects. She most recently worked on radiation detection systems and diagnostics to assess warm and hard X-rays from Z-pinch plasmas.

    Coverdale has a doctorate in plasma physics from the University of California, Davis, has authored or co-authored more than 120 papers and regularly presents at conferences. She served three terms on the Executive Committee of the IEEE Plasma Science and Applications Committee and was technical program chair for the IEEE International Conference on Plasma Science in 2009, 2010, 2012 and 2015. She also served a four-year term on the IEEE Nuclear Plasma Sciences Society Administrative Committee.

    Coverdale was on the Executive Committee of the American Physical Society (APS) Division of Plasma Physics and is senior editor for High Energy Density Physics for IEEE Transactions on Plasma Science. She is a Fellow of both the IEEE and APS.

    A mother of three, Coverdale has worked with the leadership of IEEE and APS to include more women in technical programs and award nominations, and has promoted work-life balance by helping develop a child-care grant program for the IEEE Nuclear Plasma Sciences Society. “I worked with bosses and teams who were willing to be flexible,” she said. “It’s a good thing to balance family and work. I’ve tried to impress upon my kids to choose career paths that allow you do to many things in life.”

    Coverdale mentors women in her field and speaks to aspiring female engineers through IEEE-sponsored diversity events. She also organizes and judges science fairs in local elementary schools.

    “I have been able to take advantage of many programs that encourage community involvement,” she said. “I appreciate that my family has been supportive of my career throughout, and receiving awards like these helps reinforce my belief that the skills I have developed to balance work and family are useful in both areas.”

    See the full article here .

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    Sandia Campus
    Sandia National Laboratory

    Sandia National Laboratories is a multiprogram laboratory operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy’s National Nuclear Security Administration. With main facilities in Albuquerque, N.M., and Livermore, Calif., Sandia has major R&D responsibilities in national security, energy and environmental technologies, and economic competitiveness.
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  • richardmitnick 8:11 pm on August 25, 2016 Permalink | Reply
    Tags: , Basic Research, ,   

    From JPL-Caltech: “Spitzer Space Telescope Begins ‘Beyond’ Phase” 

    NASA JPL Banner

    JPL-Caltech

    NASA Spitzer Telescope
    Spitzer

    August 25, 2016

    Elizabeth Landau
    Jet Propulsion Laboratory, Pasadena, Calif.
    818-354-6425
    elizabeth.landau@jpl.nasa.gov

    1

    Spitzer Space Telescope Begins ‘Beyond’ Phase

    This diagram shows how the different phases of Spitzer’s mission relate to its location relative to the Earth over time.Credit: NASA/JPL-Caltech

    Celebrating the spacecraft’s ability to push the boundaries of space science and technology, NASA’s Spitzer Space Telescope team has dubbed the next phase of its journey “Beyond.”

    “Spitzer is operating well beyond the limits that were set for it at the beginning of the mission,” said Michael Werner, the project scientist for Spitzer at NASA’s Jet Propulsion Laboratory in Pasadena, California. “We never envisioned operating 13 years after launch, and scientists are making discoveries in areas of science we never imagined exploring with the spacecraft.”

    NASA recently granted the spacecraft a two-and-a-half-year mission extension. This Beyond phase of the Spitzer mission will explore a wide range of topics in astronomy and cosmology, as well as planetary bodies in and out of our solar system.

    Because of Spitzer’s orbit and age, the Beyond phase presents a variety of new engineering challenges. Spitzer trails Earth in its journey around the sun, but because the spacecraft travels slower than Earth, the distance between Spitzer and Earth has widened over time. As Spitzer gets farther away, its antenna must be pointed at higher angles toward the sun to communicate with Earth, which means that parts of the spacecraft will experience more and more heat. At the same time, Spitzer’s solar panels point away from the sun and will receive less sunlight, so the batteries will be under greater stress. To enable this riskier mode of operations, the mission team will have to override some autonomous safety systems.

    “Balancing these concerns on a heat-sensitive spacecraft will be a delicate dance, but engineers are hard at work preparing for the new challenges in the Beyond phase,” said Mark Effertz, the Spitzer spacecraft chief engineer at Lockheed Martin Space Systems Company, Littleton, Colorado, which built the spacecraft.

    Spitzer, which launched on Aug. 25, 2003, has consistently adapted to new scientific and engineering challenges during its mission, and the team expects it will continue to do so during the “Beyond” phase, which begins Oct. 1. The selected research proposals for the Beyond phase, also known as Cycle 13, include a variety of objects that Spitzer wasn’t originally planned to address — such as galaxies in the early universe, the black hole at the center of the Milky Way and exoplanets.

    Sag A*  NASA Chandra X-Ray Observatory 23 July 2014, the supermassive black hole at the center of the Milky Way
    Sag A* NASA Chandra X-Ray Observatory 23 July 2014, the supermassive black hole at the center of the Milky Way

    “We never even considered using Spitzer for studying exoplanets when it launched,” said Sean Carey of NASA’s Spitzer Science Center at Caltech in Pasadena. “It would have seemed ludicrous back then, but now it’s an important part of what Spitzer does.”

    Spitzer’s exoplanet exploration

    Spitzer has many qualities that make it a valuable asset in exoplanet science, including an extremely accurate star-targeting system and the ability to control unwanted changes in temperature. Its stable environment and ability to observe stars for long periods of time led to the first detection of light from known exoplanets in 2005. More recently, Spitzer’s Infrared Array Camera (IRAC) has been used for finding exoplanets using the “transit” method — looking for a dip in a star’s brightness that corresponds to a planet passing in front of it. This brightness change needs to be measured with exquisite accuracy to detect exoplanets. IRAC scientists have created a special type of observation to make such measurements, using single pixels within the camera.

    Another planet-finding technique that Spitzer uses, but was not designed for, is called microlensing. When a star passes in front of another star, the gravity of the first star can act as a lens, making the light from the more distant star appear brighter. Scientists are using microlensing to look for a blip in that brightening, which could mean that the foreground star has a planet orbiting it. Spitzer and the ground-based Polish Optical Gravitational Lensing Experiment (OGLE) were used together to find one of the most distant planets known outside the solar system, as reported in 2015. This type of investigation is made possible by Spitzer’s increasing distance from Earth, and could not have been done early in the mission.

    Peering into the early universe

    Understanding the early universe is another area where Spitzer has broken ground. IRAC was designed to detect remote galaxies roughly 12 billion light-years away — so distant that their light has been traveling for roughly 88 percent of the history of the universe. But now, thanks to collaborations between Spitzer and NASA’s Hubble Space Telescope, scientists can peer even further into the past. The farthest galaxy ever seen, GN-z11, was characterized in a 2016 study using data from these telescopes. GN-z11 is about 13.4 billion light-years away, meaning its light has been traveling since 400 million years after the big bang.

    “When we designed the IRAC instrument, we didn’t know those more distant galaxies existed,” said Giovanni Fazio, principal investigator of IRAC, based at the Harvard Smithsonian Center for Astrophysics in Cambridge, Massachusetts. “The combination of the Hubble Space Telescope and Spitzer has been fantastic, with the telescopes working together to determine their distance, stellar mass and age.”

    Closer to home, Spitzer advanced astronomers’ understanding of Saturn when scientists using the observatory discovered the planet’s largest ring in 2009. Most of the material in this ring — consisting of ice and dust — begins 3.7 million miles (6 million kilometers) from Saturn and extends about 7.4 million miles (12 million kilometers) beyond that. Though the ring doesn’t reflect much visible light, making it difficult for Earth-based telescopes to see, Spitzer could detect the infrared glow from the cool dust.

    The multiple phases of Spitzer

    Spitzer reinvented itself in May 2009 with its warm mission, after the depletion of the liquid helium coolant that was chilling its instruments since August 2003. At the conclusion of the “cold mission,” Spitzer’s Infrared Spectrograph and Multiband Imaging Photometer stopped working, but two of the four cameras in IRAC persisted. Since then, the spacecraft has made numerous discoveries despite operating in warmer conditions (which, at about minus 405 Fahrenheit or 30 Kelvin, is still cold by Earthly standards).

    “With the IRAC team and the Spitzer Science Center team working together, we’ve really learned how to operate the IRAC instrument better than we thought we could,” Fazio said. “The telescope is also very stable and in an excellent orbit for observing a large part of the sky.”

    Spitzer’s Beyond mission phase will last until the commissioning phase of NASA’s James Webb Space Telescope, currently planned to launch in October 2018. Spitzer is set to identify targets that Webb can later observe more intensely.

    “We are very excited to continue Spitzer in its Beyond phase. We fully expect new, exciting discoveries to be made over the next two-and-a-half years,” said Suzanne Dodd, project manager for Spitzer, based at JPL.

    JPL manages the Spitzer Space Telescope mission for NASA’s Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center at Caltech in Pasadena, California. Spacecraft operations are based at Lockheed Martin Space Systems Company, Littleton, Colorado. Data are archived at the Infrared Science Archive housed at the Infrared Processing and Analysis Center at Caltech. Caltech manages JPL for NASA. For more information about Spitzer, visit:

    http://spitzer.caltech.edu

    http://www.nasa.gov/spitzer

    See the full article here .

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    NASA JPL Campus

    Jet Propulsion Laboratory (JPL) is a federally funded research and development center and NASA field center located in the San Gabriel Valley area of Los Angeles County, California, United States. Although the facility has a Pasadena postal address, it is actually headquartered in the city of La Cañada Flintridge [1], on the northwest border of Pasadena. JPL is managed by the nearby California Institute of Technology (Caltech) for the National Aeronautics and Space Administration. The Laboratory’s primary function is the construction and operation of robotic planetary spacecraft, though it also conducts Earth-orbit and astronomy missions. It is also responsible for operating NASA’s Deep Space Network.

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  • richardmitnick 2:50 pm on August 25, 2016 Permalink | Reply
    Tags: , Basic Research, , , ,   

    From JHU: “Can one cosmic enigma help solve another? Johns Hopkins researchers think so” 

    Johns Hopkins
    Johns Hopkins University

    8.24.16
    Arthur Hirsch

    1
    Image credit: VectaRay

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    A massive cluster of yellowish galaxies, seemingly caught in a red and blue spider web of eerily distorted background galaxies, makes for a spellbinding picture from the new Advanced Camera for Surveys aboard NASA’s Hubble Space Telescope. To make this unprecedented image of the cosmos, Hubble peered straight through the center of one of the most massive galaxy clusters known, called Abell 1689. The gravity of the cluster’s trillion stars — plus dark matter — acts as a 2-million-light-year-wide lens in space. This gravitational lens bends and magnifies the light of the galaxies located far behind it. Some of the faintest objects in the picture are probably over 13 billion light-years away (redshift value 6). Strong gravitational lensing as observed by the Hubble Space Telescope in Abell 1689 indicates the presence of dark matter. Credit: NASA, N. Benitez (JHU), T. Broadhurst (Racah Institute of Physics/The Hebrew University), H. Ford (JHU), M. Clampin (STScI),G. Hartig (STScI), G. Illingworth (UCO/Lick Observatory), the ACS Science Team and ESA. phys.org.

    Astrophysicists from Johns Hopkins University have proposed a clever new way of shedding light on the mysterious dark matter believed to make up most of the universe. The irony is they want to try to pin down the nature of this unexplained phenomenon by using another obscure cosmic emanation known as “fast radio bursts.”

    In a paper published today in Physical Review Letters, the team of astrophysicists argues that these extremely bright and brief flashes of radio-frequency radiation can provide clues about whether certain black holes are dark matter.

    Julian Muñoz, a Johns Hopkins graduate student and the paper’s lead author, said fast radio bursts, or FRBs, provide a direct and specific way of detecting black holes of a specific mass, which are the suspect dark matter.

    FRB Fast Radio Bursts from NAOJ Subaru
    FRB Fast Radio Bursts from NAOJ Subaru, Mauna Key, Hawaii, USA

    Muñoz wrote the paper along with Ely D. Kovetz, a post-doctoral fellow; Marc Kamionkowski, a professor in the Department of Physics and Astronomy; and Liang Dai, who completed his doctorate in astrophysics at Johns Hopkins last year. Dai is now a NASA Einstein Postdoctoral Fellow at the Institute for Advanced Study in Princeton, New Jersey.

    The paper builds on a hypothesis offered in a paper published this spring by Muñoz, Kovetz, and Kamionkowski, along with five Johns Hopkins colleagues. Also published in Physical Review Letters, that research made a speculative case that the collision of black holes detected early in the year by the Laser Interferometer Gravitational-Wave Observatory, or LIGO, was actually dark matter, a substance that makes up 85 percent of the mass of the universe.

    Gravitational waves. Credit: MPI for Gravitational Physics/W.Benger-Zib
    Credit: MPI for Gravitational Physics/W.Benger-Zib
    LSC LIGO Scientific Collaboration
    Caltech/MIT Advanced aLigo Hanford, WA, USA installation
    Caltech/MIT Advanced aLigo Hanford, WA, USA installation
    Caltech/MIT Advanced aLigo detector installation Livingston, LA, USA
    Caltech/MIT Advanced aLigo detector installation Livingston, LA, USA

    The earlier paper made what Kamionkowski called a “plausibility argument” that LIGO found dark matter. The study took as a point of departure the fact that the objects detected by LIGO fit within the predicted range of mass of so-called “primordial” black holes. Unlike black holes that formed from imploded stars, primordial black holes are believed to have formed from the collapse of large expanses of gas during the birth of the universe.

    The existence of primordial black holes has not been established with certainty, but they have been suggested before as a possible solution to the riddle of dark matter. With so little evidence of them to examine, the hypothesis had not gained a large following among scientists.

    The earlier paper made what Kamionkowski called a “plausibility argument” that LIGO found dark matter. The study took as a point of departure the fact that the objects detected by LIGO fit within the predicted range of mass of so-called “primordial” black holes. Unlike black holes that formed from imploded stars, primordial black holes are believed to have formed from the collapse of large expanses of gas during the birth of the universe.

    The LIGO findings, however, raised the prospect anew, especially as the objects detected in that experiment conform to the mass predicted for dark matter.

    The Johns Hopkins team calculated how often these primordial black holes would form binary pairs, and eventually collide. Taking into account the size and elongated shape believed to characterize primordial black hole binary orbits, the team came up with a collision rate that conforms to the LIGO findings.

    Key to the argument is that the black holes that LIGO detected fall within a range of 29 to 36 solar masses, meaning they are that many times greater than the mass of the sun. The new paper considers the question of how to test the hypothesis that dark matter consists of black holes of roughly 30 solar masses.

    That’s where the fast radio bursts come in. First observed only a few years ago, these flashes of radio frequency radiation emit intense energy, but last only fractions of a second. Their origins are unknown but are believed to lie in galaxies outside the Milky Way.

    If the speculation about their origins is true, Kamionkowski said, the radio waves would travel great distances before they’re observed on Earth, perhaps passing a black hole. According to Einstein’s theory of general relativity, the ray would be deflected when it passes a black hole. If it passes close enough, it could be split into two rays shooting off in the same direction—creating two images from one source.

    The new study shows that if the black hole has 30 times the mass of the Sun, the two images will arrive a few milliseconds apart. If 30-solar-mass black holes make up the dark matter, there is a chance that any given fast radio burst will be deflected in this way and followed in a few milliseconds by an echo.

    “The echoing of FRBs is a very direct probe of dark matter,” Muñoz said. “While gravitational waves might ‘indicate’ that dark matter is made of black holes, there are other ways to produce very-massive black holes with regular astrophysics, so it would be hard to convince oneself that we are detecting dark matter. However, gravitational lensing of fast radio bursts has a very unique signature, with no other astrophysical phenomenon that could reproduce it.”

    Kaimonkowski said that while the probability for any such FRB echo is small, “it is expected that several of the thousands of FRBs to be detected in the next few years will have such echoes … if black holes make up the dark matter.”

    So far, only about 20 fast radio bursts have been detected and recorded since 2001. The very sensitive instruments needed to detect them can look at only very small slices of the sky at a time, limiting the rate at which the bursts can be found. A new telescope expected to go into operation this year that seems particularly promising for spotting radio bursts is the Canadian Hydrogen Intensity Mapping Experiment. The joint project of the University of British Columbia, McGill University, the University of Toronto, and the Dominion Radio Astrophysical Observatory stands in British Columbia.

    “Once the thing is working up to their planned specifications, they should collect enough FRBs to begin the tests we propose,” said Kamionkowski, estimating results could be available in three to five years.

    See the full article here .

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    Johns Hopkins Campus

    The Johns Hopkins University opened in 1876, with the inauguration of its first president, Daniel Coit Gilman. “What are we aiming at?” Gilman asked in his installation address. “The encouragement of research … and the advancement of individual scholars, who by their excellence will advance the sciences they pursue, and the society where they dwell.”

    The mission laid out by Gilman remains the university’s mission today, summed up in a simple but powerful restatement of Gilman’s own words: “Knowledge for the world.”

    What Gilman created was a research university, dedicated to advancing both students’ knowledge and the state of human knowledge through research and scholarship. Gilman believed that teaching and research are interdependent, that success in one depends on success in the other. A modern university, he believed, must do both well. The realization of Gilman’s philosophy at Johns Hopkins, and at other institutions that later attracted Johns Hopkins-trained scholars, revolutionized higher education in America, leading to the research university system as it exists today.

     
  • richardmitnick 1:57 pm on August 25, 2016 Permalink | Reply
    Tags: , Basic Research, Dark galaxy Dragonfly 44, , , ,   

    From Keck: “Scientists Discover Massive Galaxy Made of 99.99 Percent Dark Matter” 

    Keck Observatory

    August 25, 2016

    SCIENCE CONTACT
    Pieter van Dokkum
    Yale University
    New Haven, Connecticut, USA
    Tel: +1-203-432-3000
    E-mail: pieter.vandokkum@yale.edu

    MEDIA CONTACT

    Steve Jefferson
    W. M. Keck Observatory
    (808) 881-3827
    sjefferson@keck.hawaii.edu

    Keck Observatory.
    Keck, with Subaru and IRTF (NASA Infrared Telescope Facility). Vadim Kurland

    Keck Observatory

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    The dark galaxy Dragonfly 44. The image on the left is a wide view of the galaxy taken with the Gemini North telescope using the Gemini Multi-Object Spectrograph (GMOS). The close-up on the right is from the same very deep image, revealing the large, elongated galaxy, and halo of spherical clusters of stars around the galaxy’s core, similar to the halo that surrounds our Milky Way Galaxy. Dragonfly 44 is very faint for its mass, and consists almost entirely of Dark Matter. Credit: Pieter van Dokkum, Roberto Abraham, Gemini; Sloan Digital Sky Survey.

    Using the world’s most powerful telescopes, an international team of astronomers has discovered a massive galaxy that consists almost entirely of Dark Matter. Using the W. M. Keck Observatory and the Gemini North telescope – both on Maunakea, Hawaii – the team found a galaxy whose mass is almost entirely Dark Matter. The findings are being published in The Astrophysical Journal Letters today.

    Gemini/North telescope at Manua Kea, Hawaii, USA
    GEMINI/North GMOS
    Gemini/North telescope at Manua Kea, Hawaii, USA; GEMINI/North GMOS

    Even though it is relatively nearby, the galaxy, named Dragonfly 44, had been missed by astronomers for decades because it is very dim. It was discovered just last year when the Dragonfly Telephoto Array observed a region of the sky in the constellation Coma.

    U Toronto Dunlap Dragonfly telescope Array
    U Toronto Dunlap Dragonfly telescope Array

    Upon further scrutiny, the team realized the galaxy had to have more than meets the eye: it has so few stars that it quickly would be ripped apart unless something was holding it together.

    To determine the amount of Dark Matter in Dragonfly 44, astronomers used the DEIMOS instrument installed on Keck II to measure the velocities of stars for 33.5 hours over a period of six nights so they could determine the galaxy’s mass.

    Keck/DEIMOS
    Keck/DEIMOS

    The team then used the Gemini Multi-Object Spectrograph (GMOS) on the 8-meter Gemini North telescope on Maunakea in Hawaii to reveal a halo of spherical clusters of stars around the galaxy’s core, similar to the halo that surrounds our Milky Way Galaxy.

    “Motions of the stars tell you how much matter there is, van Dokkum said. “They don’t care what form the matter is, they just tell you that it’s there. In the Dragonfly galaxy stars move very fast. So there was a huge discrepancy: using Keck Observatory, we found many times more mass indicated by the motions of the stars, then there is mass in the stars themselves.”

    The mass of the galaxy is estimated to be a trillion times the mass of the Sun – very similar to the mass of our own Milky Way galaxy. However, only one hundredth of one percent of that is in the form of stars and “normal” matter; the other 99.99 percent is in the form of dark matter. The Milky Way has more than a hundred times more stars than Dragonfly 44.

    Finding a galaxy with the mass of the Milky Way that is almost entirely dark was unexpected. “We have no idea how galaxies like Dragonfly 44 could have formed,” Roberto Abraham, a co-author of the study, said. “The Gemini data show that a relatively large fraction of the stars is in the form of very compact clusters, and that is probably an important clue. But at the moment we’re just guessing.”

    “This has big implications for the study of Dark Matter,” van Dokkum said. “It helps to have objects that are almost entirely made of Dark Matter so we don’t get confused by stars and all the other things that galaxies have. The only such galaxies we had to study before were tiny. This finding opens up a whole new class of massive objects that we can study.

    “Ultimately what we really want to learn is what Dark Matter is,” van Dokkum said. “The race is on to find massive dark galaxies that are even closer to us than Dragonfly 44, so we can look for feeble signals that may reveal a Dark Matter particle.”

    Additional co-authors are Shany Danieli, Allison Merritt, and Lamiya Mowla of Yale, Jean Brodie of the University of California Observatories, Charlie Conroy of Harvard, Aaron Romanowsky of San Jose State University, and Jielai Zhang of the University of Toronto.

    The W. M. Keck Observatory operates the largest, most scientifically productive telescopes on Earth. The two, 10-meter optical/infrared telescopes near the summit of Maunakea on the Island of Hawaii feature a suite of advanced instruments including imagers, multi-object spectrographs, high-resolution spectrographs, integral-field spectrographs and world-leading laser guide star adaptive optics systems.

    DEIMOS (DEep Imaging Multi-Object Spetrograph) boasts the largest field of view (16.7 arcmin by 5 arcmin) of any of the Keck Observatory instruments, and the largest number of pixels (64 Mpix). It is used primarily in its multi-object mode, obtaining simultaneous spectra of up to 130 galaxies or stars. Astronomers study fields of distant galaxies with DEIMOS, efficiently probing the most distant corners of the universe with high sensitivity.

    See the full article here .

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    Mission
    To advance the frontiers of astronomy and share our discoveries with the world.

    The W. M. Keck Observatory operates the largest, most scientifically productive telescopes on Earth. The two, 10-meter optical/infrared telescopes on the summit of Mauna Kea on the Island of Hawaii feature a suite of advanced instruments including imagers, multi-object spectrographs, high-resolution spectrographs, integral-field spectrometer and world-leading laser guide star adaptive optics systems. Keck Observatory is a private 501(c) 3 non-profit organization and a scientific partnership of the California Institute of Technology, the University of California and NASA.

    Today Keck Observatory is supported by both public funding sources and private philanthropy. As a 501(c)3, the organization is managed by the California Association for Research in Astronomy (CARA), whose Board of Directors includes representatives from the California Institute of Technology and the University of California, with liaisons to the board from NASA and the Keck Foundation.
    Keck UCal

    Keck NASA

    Keck Caltech

     
  • richardmitnick 1:19 pm on August 25, 2016 Permalink | Reply
    Tags: , ALMA Finds Unexpected Trove of Gas Around Larger Stars, , Basic Research, ,   

    From ALMA: “ALMA Finds Unexpected Trove of Gas Around Larger Stars” 

    ESO/NRAO/NAOJ ALMA Array
    ESO/NRAO/NAOJ ALMA Array in Chile in the Atacama at Chajnantor plateau, at 5,000 metres
    ALMA

    25 August 2016
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    1
    Artist impression of a debris disk surrounding a star in the Scorpius-Centaurus Association. ALMA discovered that — contrary to expectations — the more massive stars in this region retain considerable stores of carbon monoxide gas. This finding could offer new insights into the timeline for giant planet formation around young stars. Credit: NRAO/AUI/NSF; D. Berry / SkyWorks

    Astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) surveyed dozens of young stars – some Sun-like and others nearly double that size – and discovered that the larger variety have surprisingly rich reservoirs of carbon monoxide gas in their debris disks. In contrast, the lower-mass, Sun-like stars have debris disks that are virtually gas-free.

    This finding runs counter to astronomer’s expectations, which hold that stronger radiation from larger stars should strip away gas from their debris disks faster than the comparatively mild radiation from smaller stars. It may also offer new insights into the timeline for giant planet formation around young stars.

    Debris disks are found around stars that have shed their dusty, gas-filled protoplanetary disks and gone on to form planets, asteroids, comets, and other planetesimals. Around younger stars, however, many of these newly formed objects have yet to settle into stately orbits and routinely collide, producing enough rubble to spawn a “second-generation” disk of debris.

    “Previous spectroscopic measurements of debris disks revealed that certain ones had an unexpected chemical signature suggesting they had an overabundance of carbon monoxide gas,” said Jesse Lieman-Sifry, lead author on a paper published in Astrophysical Journal. At the time of the observations, Lieman-Sifry was an undergraduate astronomy major at Wesleyan University in Middletown, Connecticut. “This discovery was puzzling since astronomers believe that this gas should be long gone by the time we see evidence of a debris disk,” he said.

    In search of clues as to why certain stars harbor gas-rich disks, Lieman-Sifry and his team surveyed 24 star systems in the Scorpius-Centaurus Association. This loose stellar agglomeration, which lies a few hundred light-years from Earth, contains hundreds of low- and intermediate-mass stars. For reference, astronomers consider our Sun to be a low-mass star.

    The astronomers narrowed their search to stars between five and ten million years old — old enough to host full-fledged planetary systems and debris disks — and used ALMA to examine the millimeter-wavelength “glow” from the carbon monoxide in the star’s debris disks.

    The team carried out their survey over a total of six nights between December 2013 and December 2014, observing for a mere ten minutes each night. At the time it was conducted, this study constituted the most extensive millimeter-wavelength interferometric survey of stellar debris disks ever achieved.

    2
    ALMA image of the debris disk surrounding a star in the Scorpius-Centaurus Association known as HIP 73145. The green region maps the carbon monoxide gas that suffuses the debris disk. The red is the millimeter-wavelength light emitted by the dust surrounding the central star. The star HIP 73145 is estimated to be approximately twice the mass of the Sun. The disk in this system extends well past what would be the orbit of Neptune in our solar system, drawn in for scale. The location of the central star is also highlighted for reference. Credit: J. Lieman-Sifry, et al., ALMA (ESO/NAOJ/NRAO); B. Saxton (NRAO/AIU/NSF)

    Armed with an incredibly rich set of observations, the astronomers found the most gas-rich disks ever recorded in a single study. Among their sample of two dozen disks, the researchers spotted three that exhibited strong carbon monoxide emission. Much to their surprise, all three gas-rich disks surrounded stars about twice as massive as the Sun. None of the 16 smaller, Sun-like stars in the sample appeared to have disks with large stores of carbon monoxide. These observations suggest that larger stars are more likely to sport disks with significant gas reservoirs than Sun-like stars.

    This finding is counterintuitive, because higher-mass stars flood their planetary systems with energetic ultraviolet radiation that should destroy the carbon monoxide gas lingering in their debris disks. This new research reveals, however, that the larger stars are somehow able to either preserve or replenish their carbon monoxide stockpiles.

    “We’re not sure whether these stars are holding onto reservoirs of gas much longer than expected, or whether there’s a sort of ‘last gasp’ of second-generation gas produced by collisions of comets or evaporation from the icy mantles of dust grains,” said Meredith Hughes, an astronomer at Wesleyan University and coauthor of the study.

    The existence of this gas may have important implications for planet formation, says Hughes. Carbon monoxide is a major constituent of the atmospheres of giant planets. Its presence in debris disks could mean that other gases, including hydrogen, are present, but perhaps in much lower concentrations. If certain debris disks are able to hold onto appreciable amounts of gas, it might push back the expected deadline for giant planet formation around young stars, the astronomers speculate.

    3
    ALMA image of the debris disk surrounding a star in the Scorpius-Centaurus Association known as HIP 73145. The green region maps the carbon monoxide gas that suffuses the debris disk. The red is the millimeter-wavelength light emitted by the dust surrounding the central star. The star HIP 73145 is estimated to be approximately twice the mass of the Sun. The disk in this system extends well past what would be the orbit of Neptune in our solar system. Credit: J. Lieman-Sifry, et al., ALMA (ESO/NAOJ/NRAO); B. Saxton (NRAO/AIU/NSF)

    “Future high-resolution observations of these gas-rich systems may allow astronomers to infer the location of the gas within the disk, which may shed light on the origin of the gas,” says Antonio Hales, an astronomer with the Joint ALMA Observatory in Santiago, Chile, and the National Radio Astronomy Observatory in Charlottesville, Virginia, and coauthor on the study. “For instance, if the gas was produced by planetesimal collisions, it should be more highly concentrated in regions of the disk where those impacts occurred. ALMA is the only instrument capable of making these kind of high-resolution images.”

    According to Lieman-Sifry, these dusty disks are just as diverse as the planetary systems they accompany. The discovery that the debris disks around some larger stars retain carbon monoxide longer than their Sun-like counterparts may provide insights into the role this gas plays in the development of planetary systems.

    4
    Four out of 24 debris disks observed by ALMA in the Scorpius-Centaurus Association. Researchers were surprised to discover that the larger, more energetic stars retained much more gas in their debris disks than smaller, Sun-like stars. Credit: Lieman-Sifry et al. ALMA (ESO/NAOJ/NRAO); B. Saxton, NRAO/AUI/NSF

    Additional information

    This research is presented in the paper titled “Debris disks in the Scorpius-Centaurus OB association resolved by ALMA,” by J. Lieman-Sifry et al., published in Astrophysical Journal on 23 August 2016. [Preprint: http://arxiv.org/abs/1606.07068.

    The team is composed of Jesse Lieman-Sifry (Wesleyan Univ., Middletown, Connecticut), A. Meredith Hughes (Wesleyan Univ., Middletown, Connecticut), John M. Carpenter (California Institute of Technology, Pasadena), Uma Gorti (SETI Institute, Mountain View, California), Antonio Hales (Joint ALMA Observatory, Santiago, Chile, and National Radio Astronomy Observatory, Charlottesville, Virginia), and Kevin M. Flaherty (Wesleyan Univ., Middletown, Connecticut).

    See the full article here .

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

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

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