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  • richardmitnick 3:16 pm on July 26, 2016 Permalink | Reply
    Tags: , , NASA Goddard, NASA Team Begins Testing of a New-Fangled Optic, Variant of Fresnel Zone Plate   

    From Goddard: “NASA Team Begins Testing of a New-Fangled Optic” 

    NASA Goddard Banner

    NASA Goddard Space Flight Center

    July 26, 2016
    Lori Keesey
    NASA’s Goddard Space Flight Center

    It’s an age-old astronomical truth: To resolve smaller and smaller physical details of distant celestial objects, scientists need larger and larger light-collecting mirrors. This challenge is not easily overcome given the high cost and impracticality of building and — in the case of space observatories — launching large-aperture telescopes.

    2
    This image shows how the photon sieve brings red laser light to a pinpoint focus on its optical axis, but produces exotic diffraction patterns when viewed from the side. Credits: NASA/W. Hrybyk

    However, a team of scientists and engineers at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, has begun testing a potentially more affordable alternative called the photon sieve. This new-fangled telescope optic could give scientists the resolution they need to see finer details still invisible with current observing tools – a jump in resolution that could help answer a 50-year-old question about the physical processes heating the sun’s million-degree corona.

    Although potentially useful at all wavelengths, the team specifically is developing the photon sieve for studies of the sun in the ultraviolet, the wavelengths needed to disentangle the coronal heating mystery. With support from Goddard’s Research and Development program, the team has fabricated three sieves and now plans to begin testing to see if it can withstand the rigors of operating in space — milestones achieved in less than a year. “This is already a success,” said Doug Rabin, who is leading the R&D initiative.

    3
    This drawing shows the differences between Fresnel zone plates and the photon sieve. The latter is dotted with millions of precisely machined holes. Credits: NASA

    Variant of Fresnel Zone Plate

    The optic is a variant of something called a Fresnel zone plate. Rather than focusing light as most telescopes do through refraction or reflection, Fresnel plates cause light to diffract — a phenomenon that happens when light travels through a thin opening and then spreads out. This causes the light waves on the other side to reinforce or cancel each other out in precise patterns.

    Fresnel plates consist of a tightly spaced set of rings, alternatingly transparent or opaque. Light travels through the spaces between the opaque zones, which are precisely spaced so that the diffracted light overlaps and focuses at a specific point, creating an image that can be recorded by a solid-state sensor.

    The photon sieve operates largely the same. However, the sieve is dotted with millions of holes precisely placed on silicon in a circular pattern that takes the place of conventional Fresnel zones.

    The team wants to build a photon sieve at least three feet, or one meter, in diameter — a size they think could achieve up to 100 times better angular resolution in the ultraviolet than NASA’s high-resolution space telescope, the Solar Dynamics Observatory.

    “For more than 50 years, the central unanswered question in solar coronal science has been to understand how energy transported from below is able to heat the corona,” Rabin said. “Current instruments have spatial resolutions about 100 times larger than the features that must be observed to understand this process.”

    Rabin believes his team is well along the way in building an optic that can help answer the question.

    Millions of Holes

    In just a few months’ time, his team built three devices measuring three inches wide — five times larger than the initial 17-millimeter optic developed four years ago under a previous R&D-funded effort. Each device contains 16 million holes whose sizes and locations were determined by team member Adrian Daw. Another team member, Kevin Denis, then etched the holes in a silicon wafer to Daw’s exacting specifications using a fabrication technique called photolithography.

    Team members Anne-Marie Novo-Gradac and John O’Neill have acquired optical images with the new photon sieves, while Tom Widmyer and Greg Woytko have prepared them for vibration testing to make sure they can survive harsh g-forces encountered during launch.

    “This testing is to prove that the photon sieve will work as well as theory predicts,” Rabin said. Although the team has already accomplished nearly all the goals it set forth when work began late last year, Rabin believes the team can enlarge the optics by a factor of two before the end of the fiscal year.

    Formation-Flying CubeSat

    But the work likely won’t end there. In the nearer term, Rabin believes his team can mature the technology for a potential sounding-rocket demonstration. In the longer term, he and team member Joe Davila envision the optic flying on a two-spacecraft formation-flying CubeSat-type mission designed specifically to study the sun’s corona.

    “The scientific payoff is a feasible and cost-effective means of achieving the resolution necessary to answer a key problem in solar physics,” he said.

    For more technology news, go to: http://gsfctechnology.gsfc.nasa.gov/newsletter/Current.pdf

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    NASA’s Goddard Space Flight Center is home to the nation’s largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe.

    Named for American rocketry pioneer Dr. Robert H. Goddard, the center was established in 1959 as NASA’s first space flight complex. Goddard and its several facilities are critical in carrying out NASA’s missions of space exploration and scientific discovery.

    NASA Goddard Campus
    NASA/Goddard Campus
    NASA

     
  • richardmitnick 12:56 pm on July 14, 2016 Permalink | Reply
    Tags: , NASA Goddard, , NASA REXIS   

    From Goddard: “NASA Instrument to Use X-Rays to Map an Asteroid” 

    NASA Goddard Banner

    NASA Goddard Space Flight Center

    July 12, 2016
    Sarah Schlieder
    sarah.schlieder@nasa.gov
    NASA’s Goddard Space Flight Center in Greenbelt, Md.

    1
    REXIS. No image caption. No image credit.

    NASA’s OSIRIS-REx spacecraft will launch September 2016 and travel to the near-Earth asteroid Bennu to harvest a sample of surface material and return it to Earth for study. But before the science team selects a sample site, they can find out a bit about Bennu’s elemental make-up.

    NASA OSIRIS-Rex Spacecraft
    NASA/OSIRIS-Rex Spacecraft

    To determine the composition of Bennu’s surface, the Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer (OSIRIS-REx) team equipped the spacecraft with an instrument that will identify which elements are present on the asteroid and measure their abundance.


    NASAs OSIRIS-REx mission launches in September 2016 and plans to return a sample of asteroid Bennu to Earth in 2023.
    Access mp4 video here .

    The Regolith X-ray Imaging Spectrometer, or REXIS can image X-ray emission from Bennu in order to provide an elemental abundance map of the asteroid’s surface.

    “REXIS is different from the other imaging instruments on OSIRIS-REx because we’re going to determine what Bennu is made of at the level of individual atomic elements,” said Richard Binzel, REXIS principal investigator and instrument scientist at the Massachusetts Institute of Technology (MIT), Cambridge. “We’re sniffing the atoms on the surface of Bennu.”

    To do that, REXIS gets a little help from the sun. Atoms on Bennu’s surface absorb incoming solar X-rays that are emitted along with the solar wind. This causes electrons in the atom to move to a higher energy level. However, because these excited electrons are unstable, they quickly de-excite and drop back down to their original energy level and emit their own X-ray in turn. This process is known as fluorescence.

    “You have all this energy coming in, and it kicks electrons up to the next energy level, but the electrons quickly decay back down and emit X-rays of precisely that same energy,” said Josh Grindlay, REXIS co-principal investigator and deputy instrument scientist at Harvard University, Cambridge, Massachusetts. “The net result is a glowing surface on Bennu.”

    The energies of the re-emitted X-rays are characteristic of the elements from which they came. Elements absorb and re-emit X-rays at different, specific energies. The energies that the science team will see glowing at Bennu’s surface will tell the researchers which elements are present.

    In order to map these emitted X-rays, REXIS is fitted with what’s known as a coded aperture mask. The mask consists of a pattern of pinholes that, when X-rays shine through, creates a shadow pattern on REXIS’ detector.

    Imagine sitting in your bedroom at night and a car drives by. The headlights cast a pattern of light and shadow on the walls. As the car moves, so do the shadows. In REXIS’ case, it’s the spacecraft that moves over the asteroid surface. The changing shadow patterns allow the team to identify any particular bright spots on Bennu that might be especially abundant in a certain element.

    REXIS was selected as a Student Collaboration Experiment for the OSIRIS-REx mission. Built by a team from MIT and Harvard, students will perform data analysis of REXIS as part of their coursework.

    “This has been an amazing experience for the students,” said Rebecca Masterson, REXIS co-principal investigator and instrument manager at MIT. “They get to see how a mission evolves and what it takes to get to the point of launch. They’re getting to see how an idea goes from conception to completion and actually play a role in its success.”

    More than 100 students will have been involved in REXIS upon the completion of the OSIRIS-REx mission.

    “Even though OSIRIS-REx hasn’t left the ground, I think REXIS is already a success,” said David Miller, NASA’s chief technologist and a former REXIS team lead at MIT. “We’ve inspired so many students. They are our next generation of space scientists and engineers, and they’ve already had a profound impact on our abilities to go further and explore deep space.”

    Goddard provides overall mission management, systems engineering and safety and mission assurance for OSIRIS-REx. Dante Lauretta is the mission’s principal investigator at the University of Arizona. Lockheed Martin Space Systems in Denver built the spacecraft. OSIRIS-REx is the third mission in NASA’s New Frontiers Program. NASA’s Marshall Space Flight Center in Huntsville, Alabama, manages New Frontiers for the agency’s Science Mission Directorate in Washington.

    For more information about OSIRIS-REx, visit:

    http://www.nasa.gov/osiris-rex

    http://www.asteroidmission.org

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    NASA’s Goddard Space Flight Center is home to the nation’s largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe.

    Named for American rocketry pioneer Dr. Robert H. Goddard, the center was established in 1959 as NASA’s first space flight complex. Goddard and its several facilities are critical in carrying out NASA’s missions of space exploration and scientific discovery.

    NASA Goddard Campus
    NASA/Goddard Campus
    NASA

     
  • richardmitnick 8:34 pm on June 29, 2016 Permalink | Reply
    Tags: , , , NASA Goddard,   

    From Goddard: “NASA’s OSIRIS-REx Gears up for 3-D Mapping on the Fly” 

    NASA Goddard Banner
    NASA Goddard Space Flight Center

    June 29, 2016
    Elizabeth Zubritsky
    elizabeth.a.zubritsky@nasa.gov
    NASA’S Goddard Space Flight Center, Greenbelt, Maryland

    Scheduled for launch on Sept. 8, NASA’s OSIRIS-REx mission will travel to an asteroid, study it and return a sample to Earth for analysis. All of these goals depend on accurate mapping of the target, Bennu, so the team is gearing up for the challenges of cartography of an asteroid.

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    Bennu with OSIRIS-REx

    NASA OSIRIS-Rex Spacecraft
    NASA OSIRIS-Rex Spacecraft

    “Mapping of Bennu is necessary, of course, but it’s also an exciting and technically interesting aspect of the mission,” said Ed Beshore, OSIRIS-REx deputy principal investigator at the University of Arizona in Tucson. The mission is managed by NASA’s Goddard Space Flight Center in Greenbelt, Maryland.

    The maps will be generated using information gathered by the five instruments aboard OSIRIS-REx, which stands for Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer. Upon its rendezvous with Bennu, the spacecraft will spend a year surveying the asteroid for both scientific and operations purposes – including searching for plumes of material coming from the asteroid, measuring non-gravitational forces acting on Bennu, and identifying the best location to collect a sample.

    Most of the mapping work will be done during this survey phase. The team will document the shape of the asteroid, generate a suite of top-level maps, and perform reconnaissance on the final few candidates on the list of possible sampling sites. The reconnaissance maps will be so detailed that team members will be able to spot individual pebbles measuring about three-fourths of an inch (2 centimeters) across – roughly the maximum size of material that the sampling head can collect.

    “Everything the spacecraft learns will be woven together like a tapestry to tell the story of Bennu,” said Kevin Walsh, an OSIRIS-REx co-investigator at the Southwest Research Institute in Boulder, Colorado.

    In the meantime, the groundwork for mapping is being laid.

    The underlying framework is a 3-D shape model. This step is crucial because asteroids, unlike planets and moons, aren’t nice and round. They tend to be bumpy and irregular, often like potatoes. Bennu is more of a lumpy ball that gets thicker around the middle – a shape astronomers compare to a spinning top.

    This rough shape was determined from radar studies conducted from Earth since the asteroid’s discovery in 1999. After OSIRIS-REx surveys Bennu, a new model that captures the subtleties of the asteroid’s shape will be developed.

    For the global maps, information from the spacecraft’s instruments will be overlaid on the shape model. The team plans to incorporate some of these 3-D maps as a routine part of mission-critical operations. Three top-level operations maps are planned: one to evaluate which areas are safe enough to allow the spacecraft to move close to the asteroid, one to determine where the sampling arm can make good contact with the surface to perform its touch-and-go maneuver, and one to indicate where to find the material most suitable for sampling. A fourth top-level map will evaluate how scientifically valuable different regions of the asteroid are.

    “These four maps will be the key to selecting a sampling site,” said Lucy Lim, OSIRIS-REx assistant project scientist at Goddard. “To make sure the map-making goes smoothly once we arrive at Bennu, we started developing the algorithms and practicing all the steps long before launch.”

    Preparations also include establishing map conventions, such as specifying which of Bennu’s poles is north. The team based this decision on the direction of the asteroid’s rotation – a choice that fits with guidelines from the International Astronomical Union. Bennu spins in the direction opposite to Earth, so the asteroid’s poles are reversed compared to our planet’s poles.

    The location of Bennu’s prime meridian – zero degrees longitude – also has been chosen. It runs through a large bump seen on the preliminary shape model. Later, this selection will be refined, or perhaps redefined, depending on what Bennu looks like up close.

    “We make as many decisions about mapping as we can ahead of time, because the work will be intensive once we arrive at Bennu,” said Daniella DellaGiustina, the OSIRIS-REx lead image processing scientist at the University of Arizona. “But we have to allow some flexibility to make changes later, if we need to.”

    Navigation is another special consideration when mapping Bennu. Because the asteroid is so small, its gravitational force is very weak, accounting for only about half of the total force the orbiting spacecraft will feel when it’s close to Bennu. The other half will come from pressure due to sunlight on the surface of the spacecraft.

    The pressure exerted by sunlight is difficult to model, so the navigation team will have to perform frequent updates – perhaps daily. The instrument teams will have to adjust quickly to the changes in plans.

    “This won’t be an orbit the way we usually think of one – that’s how important this force will be,” said Michael Moreau, OSIRIS-REx flight dynamics system manager at Goddard. “OSIRIS-REx is going to take this work to a new level at Bennu.”

    NASA Goddard Space Flight Center in Greenbelt, Maryland provides overall mission management, systems engineering and safety and mission assurance for OSIRIS-REx. Dante Lauretta is the mission’s principal investigator at the University of Arizona, Tucson. Lockheed Martin Space Systems in Denver is building the spacecraft. OSIRIS-REx is the third mission in NASA’s New Frontiers Program. NASA Marshall Space Flight Center in Huntsville, Alabama, manages New Frontiers for the agency’s Science Mission Directorate in Washington.

    Launch management is the responsibility of NASA’s Launch Services Program at the Kennedy Space Center in Florida.

    OSIRIS-Rex instruments

    NASA OSIRIS REX OLA
    NASA OSIRIS REX OLA

    NASA OSIRIS REX OTES
    NASA OSIRIS REX OTES

    NASA OSIRIS-REX OVIRS
    NASA OSIRIS-REX OVIRS

    NASA OSIRIS REX FEROS
    NASA OSIRIS REX FEROS

    These instruments will be dealt with in future posts.

    For more information on OSIRIS-REx visit:
    http://www.nasa.gov/osiris-rex
    and
    http://www.asteroidmission.org

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    NASA’s Goddard Space Flight Center is home to the nation’s largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe.

    Named for American rocketry pioneer Dr. Robert H. Goddard, the center was established in 1959 as NASA’s first space flight complex. Goddard and its several facilities are critical in carrying out NASA’s missions of space exploration and scientific discovery.

    NASA Goddard Campus
    NASA/Goddard Campus
    NASA

     
  • richardmitnick 7:46 am on June 24, 2016 Permalink | Reply
    Tags: , , NASA Goddard,   

    From Goddard: “X-ray Echoes of a Shredded Star Provide Close-up of ‘Killer’ Black Hole” 

    NASA Goddard Banner

    NASA Goddard Space Flight Center

    June 22, 2016
    Francis Reddy
    NASA’s Goddard Space Flight Center, Greenbelt, Maryland
    francis.j.reddy@nasa.gov

    Some 3.9 billion years ago in the heart of a distant galaxy, the intense tidal pull of a monster black hole shredded a star that passed too close. When X-rays produced in this event first reached Earth on March 28, 2011, they were detected by NASA’s Swift satellite, which notified astronomers around the world.

    NASA/SWIFT Telescope
    NASA/SWIFT Telescope

    Within days, scientists concluded that the outburst, now known as Swift J1644+57, represented both the tidal disruption of a star and the sudden flare-up of a previously inactive black hole.


    Access mp4 video here .
    NASA Goddard astronomer Erin Kara discusses the discovery of X-ray echoes from Swift J1644+57, a black hole that shattered a passing star. X-rays produced by flares near this million-solar-mass black hole bounced off the nascent accretion disk and revealed its structure. Credits: NASA’s Goddard Space Flight Center

    Now astronomers using archival observations from Swift, the European Space Agency’s (ESA) XMM-Newton observatory and the Japan-led Suzaku satellite have identified the reflections of X-ray flares erupting during the event.

    ESA/XMM Newton
    ESA/XMM Newton

    JAXA/Suzaku satellite
    JAXA/Suzaku satellite

    Led by Erin Kara, a postdoctoral researcher at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and the University of Maryland, College Park (UMCP), the team has used these light echoes, or reverberations, to map the flow of gas near a newly awakened black hole for the first time.

    “While we don’t yet understand what causes X-ray flares near the black hole, we know that when one occurs we can detect its echo a couple of minutes later, once the light has reached and illuminated parts of the flow,” Kara explained. “This technique, called X-ray reverberation mapping, has been previously used to explore stable disks around black holes, but this is the first time we’ve applied it to a newly formed disk produced by a tidal disruption.”


    Access mp4 video here .
    Astronomers using data from the European Space Agency’s XMM-Newton satellite have found a long-sought X-ray signal from NGC 4151, a galaxy that contains a supermassive black hole. When the black hole’s X-ray source flares, its accretion disk brightens about half an hour later. The discovery promises a new way to unravel what’s happening in the neighborhood of these powerful objects. Credit: NASA’s Goddard Space Flight Center

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    In this artist’s rendering, a thick accretion disk has formed around a supermassive black hole following the tidal disruption of a star that wandered too close. Stellar debris has fallen toward the black hole and collected into a thick chaotic disk of hot gas. Flashes of X-ray light near the center of the disk result in light echoes that allow astronomers to map the structure of the funnel-like flow, revealing for the first time strong gravity effects around a normally quiescent black hole. Credits: NASA/Swift/Aurore Simonnet, Sonoma State University

    Stellar debris falling toward a black hole collects into a rotating structure called an accretion disk. There the gas is compressed and heated to millions of degrees before it eventually spills over the black hole’s event horizon, the point beyond which nothing can escape and astronomers cannot observe. The Swift J1644+57 accretion disk was thicker, more turbulent and more chaotic than stable disks, which have had time to settle down into an orderly routine. The researchers present the findings in a paper published online in the journal Nature on Wed., June 22.

    One surprise from the study is that high-energy X-rays arise from the inner part of the disk. Astronomers had thought most of this emission originated from a narrow jet of particles accelerated to near the speed of light. In blazars, the most luminous galaxy class powered by supermassive black holes, jets produce most of the highest-energy emission.

    “We do see a jet from Swift J1644, but the X-rays are coming from a compact region near the black hole at the base of a steep funnel of inflowing gas we’re looking down into,” said co-author Lixin Dai, a postdoctoral researcher at UMCP. “The gas producing the echoes is itself flowing outward along the surface of the funnel at speeds up to half the speed of light.”

    X-rays originating near the black hole excite iron ions in the whirling gas, causing them to fluoresce with a distinctive high-energy glow called iron K-line emission. As an X-ray flare brightens and fades, the gas follows in turn after a brief delay depending on its distance from the source.

    “Direct light from the flare has different properties than its echo, and we can detect reverberations by monitoring how the brightness changes across different X-ray energies,” said co-author Jon Miller, a professor of astronomy at the University of Michigan in Ann Arbor.

    Swift J1644+57 is one of only three tidal disruptions that have produced high-energy X-rays, and to date it remains the only event caught at the peak of this emission. These star shredding episodes briefly activate black holes astronomers wouldn’t otherwise know about. For every black hole now actively accreting gas and producing light, astronomers think nine others are dormant and dark. These quiescent black holes were active when the universe was younger, and they played an important role in how galaxies evolved. Tidal disruptions therefore offer a glimpse of the silent majority of supersized black holes.

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    Images from Swift’s Ultraviolet/Optical (white, purple) and X-Ray telescopes (yellow and red) were combined in this composite of Swift J1644+57, an X-ray outburst astronomers classify as a tidal disruption event. The event is seen only in the X-ray image, which is a 3.4-hour exposure taken on March 28, 2011. The outburst was triggered when a passing star came too close to a supermassive black hole. The star was torn apart, and much of the gas fell toward the black hole. To date, this is the only tidal disruption event emitting high-energy X-rays that astronomers have caught at peak luminosity. Credits: NASA/Swift/Stefan Immler

    “If we only look at active black holes, we might be getting a strongly biased sample,” said team member Chris Reynolds, a professor of astronomy at UMCP. “It could be that these black holes all fit within some narrow range of spins and masses. So it’s important to study the entire population to make sure we’re not biased.”

    The researchers estimate the mass of the Swift J1644+57 black hole at about a million times that of the sun but did not measure its spin. With future improvements in understanding and modeling accretion flows, the team thinks it may be possible to do so.

    ESA’s XMM-Newton satellite was launched in December 1999 from Kourou, French Guiana. NASA funded elements of the XMM-Newton instrument package and provides the NASA Guest Observer Facility at Goddard, which supports use of the observatory by U.S. astronomers. Suzaku operated from July 2005 to August 2015 and was developed at the Japanese Institute of Space and Astronautical Science, which is part of the Japan Aerospace Exploration Agency, in collaboration with NASA and other Japanese and U.S. institutions.

    NASA’s Swift satellite was launched in November 2004 and is managed by Goddard. It is operated in collaboration with Penn State University in University Park, the Los Alamos National Laboratory in New Mexico, and Orbital Sciences Corp. in Dulles, Virginia, with international collaborators in the U.K., Italy, Germany and Japan.

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    NASA’s Goddard Space Flight Center is home to the nation’s largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe.

    Named for American rocketry pioneer Dr. Robert H. Goddard, the center was established in 1959 as NASA’s first space flight complex. Goddard and its several facilities are critical in carrying out NASA’s missions of space exploration and scientific discovery.

    NASA Goddard Campus
    NASA/Goddard Campus
    NASA

     
  • richardmitnick 10:15 am on June 22, 2016 Permalink | Reply
    Tags: , , , , NASA Goddard, ,   

    From Goddard: “Astronomers Find the First ‘Wind Nebula’ Around a Magnetar” 

    NASA Goddard Banner
    NASA Goddard Space Flight Center

    June 21, 2016
    Francis Reddy
    francis.j.reddy@nasa.gov
    NASA’s Goddard Space Flight Center, Greenbelt, Maryland

    Astronomers have discovered a vast cloud of high-energy particles called a wind nebula around a rare ultra-magnetic neutron star, or magnetar, for the first time. The find offers a unique window into the properties, environment and outburst history of magnetars, which are the strongest magnets in the universe.

    1
    This X-ray image shows extended emission around a source known as Swift J1834.9-0846, a rare ultra-magnetic neutron star called a magnetar. The glow arises from a cloud of fast-moving particles produced by the neutron star and corralled around it. Color indicates X-ray energies, with 2,000-3,000 electron volts (eV) in red, 3,000-4,500 eV in green, and 5,000 to 10,000 eV in blue. The image combines observations by the European Space Agency’s XMM-Newton spacecraft taken on March 16 and Oct. 16, 2014. Credits: ESA/XMM-Newton/Younes et al. 2016

    ESA/XMM Newton
    ESA/XMM Newton

    A neutron star is the crushed core of a massive star that ran out of fuel, collapsed under its own weight, and exploded as a supernova. Each one compresses the equivalent mass of half a million Earths into a ball just 12 miles (20 kilometers) across, or about the length of New York’s Manhattan Island. Neutron stars are most commonly found as pulsars, which produce radio, visible light, X-rays and gamma rays at various locations in their surrounding magnetic fields. When a pulsar spins these regions in our direction, astronomers detect pulses of emission, hence the name.

    2
    This illustration compares the size of a neutron star to Manhattan Island in New York, which is about 13 miles long. A neutron star is the crushed core left behind when a massive star explodes as a supernova and is the densest object astronomers can directly observe. Credits: NASA’s Goddard Space Flight Center

    Typical pulsar magnetic fields can be 100 billion to 10 trillion times stronger than Earth’s. Magnetar fields reach strengths a thousand times stronger still, and scientists don’t know the details of how they are created. Of about 2,600 neutron stars known, to date only 29 are classified as magnetars.

    The newfound nebula surrounds a magnetar known as Swift J1834.9-0846 — J1834.9 for short — which was discovered by NASA’s Swift satellite on Aug. 7, 2011, during a brief X-ray outburst.

    NASA/SWIFT Telescope
    NASA/SWIFT Telescope

    Astronomers suspect the object is associated with the W41 supernova remnant, located about 13,000 light-years away in the constellation Scutum toward the central part of our galaxy.

    “Right now, we don’t know how J1834.9 developed and continues to maintain a wind nebula, which until now was a structure only seen around young pulsars,” said lead researcher George Younes, a postdoctoral researcher at George Washington University in Washington. “If the process here is similar, then about 10 percent of the magnetar’s rotational energy loss is powering the nebula’s glow, which would be the highest efficiency ever measured in such a system.”

    A month after the Swift discovery, a team led by Younes took another look at J1834.9 using the European Space Agency’s (ESA) XMM-Newton X-ray observatory, which revealed an unusual lopsided glow about 15 light-years across centered on the magnetar. New XMM-Newton observations in March and October 2014, coupled with archival data from XMM-Newton and Swift, confirm this extended glow as the first wind nebula ever identified around a magnetar. A paper describing the analysis will be published by The Astrophysical Journal.

    “For me the most interesting question is, why is this the only magnetar with a nebula? Once we know the answer, we might be able to understand what makes a magnetar and what makes an ordinary pulsar,” said co-author Chryssa Kouveliotou, a professor in the Department of Physics at George Washington University’s Columbian College of Arts and Sciences.

    The most famous wind nebula, powered by a pulsar less than a thousand years old, lies at the heart of the Crab Nebula supernova remnant in the constellation Taurus. Young pulsars like this one rotate rapidly, often dozens of times a second. The pulsar’s fast rotation and strong magnetic field work together to accelerate electrons and other particles to very high energies. This creates an outflow astronomers call a pulsar wind that serves as the source of particles making up in a wind nebula.

    Supernova remnant Crab nebula. NASA/ESA Hubble
    The best-known wind nebula is the Crab Nebula, located about 6,500 light-years away in the constellation Taurus. At the center is a rapidly spinning neutron star that accelerates charged particles like electrons to nearly the speed of light. As they whirl around magnetic field lines, the particles emit a bluish glow. This image is a composite of Hubble observations taken in late 1999 and early 2000. The Crab Nebula spans about 11 light-years. Credits: NASA, ESA, J. Hester and A. Loll (Arizona State University)

    “Making a wind nebula requires large particle fluxes, as well as some way to bottle up the outflow so it doesn’t just stream into space,” said co-author Alice Harding, an astrophysicist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “We think the expanding shell of the supernova remnant serves as the bottle, confining the outflow for a few thousand years. When the shell has expanded enough, it becomes too weak to hold back the particles, which then leak out and the nebula fades away.” This naturally explains why wind nebulae are not found among older pulsars, even those driving strong outflows.

    A pulsar taps into its rotational energy to produce light and accelerate its pulsar wind. By contrast, a magnetar outburst is powered by energy stored in the super-strong magnetic field. When the field suddenly reconfigures to a lower-energy state, this energy is suddenly released in an outburst of X-rays and gamma rays. So while magnetars may not produce the steady breeze of a typical pulsar wind, during outbursts they are capable of generating brief gales of accelerated particles.

    “The nebula around J1834.9 stores the magnetar’s energetic outflows over its whole active history, starting many thousands of years ago,” said team member Jonathan Granot, an associate professor in the Department of Natural Sciences at the Open University in Ra’anana, Israel. “It represents a unique opportunity to study the magnetar’s historical activity, opening a whole new playground for theorists like me.”

    ESA’s XMM-Newton satellite was launched on Dec. 10, 1999, from Kourou, French Guiana, and continues to make observations. NASA funded elements of the XMM-Newton instrument package and provides the NASA Guest Observer Facility at Goddard, which supports use of the observatory by U.S. astronomers.

    See the full article here.

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    NASA’s Goddard Space Flight Center is home to the nation’s largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe.

    Named for American rocketry pioneer Dr. Robert H. Goddard, the center was established in 1959 as NASA’s first space flight complex. Goddard and its several facilities are critical in carrying out NASA’s missions of space exploration and scientific discovery.

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  • richardmitnick 6:56 pm on June 13, 2016 Permalink | Reply
    Tags: , , NASA Goddard, , New Planet Is Largest Discovered That Orbits Two Suns   

    From Goddard: “New Planet Is Largest Discovered That Orbits Two Suns” 

    NASA Goddard Banner

    NASA Goddard Space Flight Center

    June 13, 2016
    Ashley Morrow

    1
    Artist’s impression of the simultaneous stellar eclipse and planetary transit events on Kepler-1647.Credits: Lynette Cook

    If you cast your eyes toward the constellation Cygnus, you’ll be looking in the direction of the largest planet yet discovered around a double-star system. It’s too faint to see with the naked eye, but a team led by astronomers from NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and San Diego State University (SDSU) in California, used NASA’s Kepler Space Telescope to identify the new planet, Kepler-1647b.

    The discovery was announced today in San Diego at a meeting of the American Astronomical Society. The research has been accepted for publication in the Astrophysical Journal with Veselin Kostov, a NASA Goddard postdoctoral fellow, as lead author.

    Kepler-1647 is 3,700 light-years away and approximately 4.4 billion years old, roughly the same age as Earth. The stars are similar to the sun, with one slightly larger than our home star and the other slightly smaller. The planet has a mass and radius nearly identical to that of Jupiter, making it the largest transiting circumbinary planet ever found.

    Planets that orbit two stars are known as circumbinary planets, or sometimes “Tatooine” planets, after Luke Skywalker’s home world in “Star Wars.” Using Kepler data, astronomers search for slight dips in brightness that hint a planet might be passing or transiting in front of a star, blocking a tiny amount of the star’s light.

    “But finding circumbinary planets is much harder than finding planets around single stars,” said SDSU astronomer William Welsh, one of the paper’s coauthors. “The transits are not regularly spaced in time and they can vary in duration and even depth.”

    2
    Comparison of the relative sizes of several Kepler circumbinary planets. Kepler-1647 b is substantially larger than any of the previously known circumbinary planets. Credits: Lynette Cook

    3
    A bird’s eye view comparison of the orbits of the Kepler circumbinary planets. Kepler-1647 b’s orbit, shown in red, is much larger than the other planets (shown in gray). For comparison, the Earth’s orbit is shown in blue. Credits: B. Quarles

    “It’s a bit curious that this biggest planet took so long to confirm, since it is easier to find big planets than small ones,” said SDSU astronomer Jerome Orosz, a coauthor on the study. “But it is because its orbital period is so long.”

    The planet takes 1,107 days – just over three years – to orbit its host stars, the longest period of any confirmed transiting exoplanet found so far. The planet is also much further away from its stars than any other circumbinary planet, breaking with the tendency for circumbinary planets to have close-in orbits. Interestingly, its orbit puts the planet with in the so-called habitable zone–the range of distances from a star where liquid water might pool on the surface of an orbiting planet

    Like Jupiter, however, Kepler-1647b is a gas giant, making the planet unlikely to host life. Yet if the planet has large moons, they could potentially be suitable for life.

    “Habitability aside, Kepler-1647b is important because it is the tip of the iceberg of a theoretically predicted population of large, long-period circumbinary planets,” said Welsh.

    Once a candidate planet is found, researchers employ advanced computer programs to determine if it really is a planet. It can be a grueling process.

    Laurance Doyle, a coauthor on the paper and astronomer at the SETI Institute, noticed a transit back in 2011. But more data and several years of analysis were needed to confirm the transit was indeed caused by a circumbinary planet. A network of amateur astronomers in the Kilodegree Extremely Little Telescope “Follow-Up Network” provided additional observations that helped the researchers estimate the planet’s mass.

    For more information about the Kepler mission, please see:

    http://www.nasa.gov/kepler

    A preprint of the paper can be found at:

    http://arxiv.org/pdf/1512.00189v2

    High-resolution artwork can be obtained at:

    http://go.sdsu.edu/kepler/

    See the full article here.

    Please help promote STEM in your local schools.

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    Stem Education Coalition

    NASA’s Goddard Space Flight Center is home to the nation’s largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe.

    Named for American rocketry pioneer Dr. Robert H. Goddard, the center was established in 1959 as NASA’s first space flight complex. Goddard and its several facilities are critical in carrying out NASA’s missions of space exploration and scientific discovery.

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  • richardmitnick 12:24 pm on June 3, 2016 Permalink | Reply
    Tags: , , Hubble Rocks with a Heavy-Metal Home, NASA Goddard   

    From Goddard: “Hubble Rocks with a Heavy-Metal Home” 

    NASA Goddard Banner

    NASA Goddard Space Flight Center

    June 3, 2016
    Ashley Morrow

    1

    This 10.5-billion-year-old globular cluster, NGC 6496, is home to heavy-metal stars of a celestial kind! The stars comprising this spectacular spherical cluster are enriched with much higher proportions of metals — elements heavier than hydrogen and helium are curiously known as metals in astronomy — than stars found in similar clusters.

    A handful of these high-metallicity stars are also variable stars, meaning that their brightness fluctuates over time. NGC 6496 hosts a selection of long-period variables — giant pulsating stars whose brightness can take up to, and even over, a thousand days to change — and short-period eclipsing binaries, which dim when eclipsed by a stellar companion.

    The nature of the variability of these stars can reveal important information about their mass, radius, luminosity, temperature, composition, and evolution, providing astronomers with measurements that would be difficult or even impossible to obtain through other methods.

    NGC 6496 was discovered in 1826 by Scottish astronomer James Dunlop. The cluster resides at about 35,000 light-years away in the southern constellation of Scorpius (The Scorpion).

    See the full article here.

    Please help promote STEM in your local schools.

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    Stem Education Coalition

    NASA’s Goddard Space Flight Center is home to the nation’s largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe.

    Named for American rocketry pioneer Dr. Robert H. Goddard, the center was established in 1959 as NASA’s first space flight complex. Goddard and its several facilities are critical in carrying out NASA’s missions of space exploration and scientific discovery.

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  • richardmitnick 12:03 pm on May 26, 2016 Permalink | Reply
    Tags: , NASA Goddard, NASA Scientists Explain the Art of Creating Digital Hurricanes   

    From Goddard: “NASA Scientists Explain the Art of Creating Digital Hurricanes” 

    NASA Goddard Banner

    NASA Goddard Space Flight Center

    May 25, 2016
    Ashley Morrow

    1
    NASA tropical meteorologists Marangelly Fuentes, left, and Oreste Reale pose with a hyperwall display of the Global Modeling and Assimilation Office’s simulation of a hurricane. Credits: NASA/Goddard/Deb McCallum

    Every day, scientists at NASA work on creating better hurricanes – on a computer screen. At NASA’s Goddard Space Flight Center in Greenbelt, Maryland, a team of scientists spends its days incorporating millions of atmospheric observations, sophisticated graphic tools and lines of computer code to create computer models simulating the weather and climate conditions responsible for hurricanes. Scientists use these models to study the complex environment and structure of tropical storms and hurricanes.

    Getting the simulations right has huge societal implications, which is why one Goddard scientist chose this line of work.

    “Freshwater floods, often caused by hurricanes, are the number one cause of death by natural disasters in the world, even above earthquakes and volcanoes,” tropical meteorologist Oreste Reale with Goddard’s Global Modeling and Assimilation Office (GMAO) said. “Seeing how the research we do could have an impact on these things is very rewarding.”

    Improved models can lead to better prediction and warning for these natural disasters, mitigating loss of life and property.

    Getting to the point of being able to accurately study hurricanes using computer models, however, is not easy. Because hurricanes are such complex storm systems, capturing their full nature in detail using a computer simulation is far from simple.

    “We need to add complexity all the time and nobody here is afraid of doing that,” Reale said. “You don’t want a simple solution. If it’s simple, chances are it’s not true.”

    Adding complexity can include updating the models, incorporating data from new satellites, replacing old satellites and more.


    Improving hurricane forecasts means testing historical storms with today’s sophisticated models and supercomputers. NASA and NOAA work together in gathering ground and satellite observations, as well as experimenting with research forecast models. As a result of this collaboration, model resolution has increased, and scientists are discovering more about the processes that occur within these powerful storms. The Global Precipitation Measurement (GPM) mission is a joint NASA and Japan Aerospace Exploration Agency (JAXA) mission that measures all forms of precipitation around the globe. GPM’s Microwave Imager, or GMI, has proven useful in seeing beneath the swirling clouds and into the structure of tropical cyclones. The information gathered by GPM and other missions will be used to improve forecast models. Music: Chris White, “Afterglow” Credits: NASA Goddard/Ryan Fitzgibbons.
    Access mp4 video here .

    Reale and his colleague, Goddard tropical meteorologist Marangelly Fuentes, have more than 25 years’ combined experience looking at modeled storms. In fact, Fuentes was Reale’s student intern while she was earning her doctorate degree at Howard University in Washington, D.C. They belong to a team in the GMAO whose goal is to assess whether new data types are used efficiently in computer models, and to ensure that changes and updates improve the performance of models and their data assimilation systems compared to previous versions. Data assimilation refers to the process through which data or observations are incorporated into an existing model.

    “Mostly I look at tropical forecasting and the analysis of tropical cyclones in the models, so we monitor how the different models are performing with tropical storms,” Fuentes said.

    This includes comparing the performance of GMAO’s weather and climate models with others in the U.S. and around the world. Fuentes looks at current versions of the GMAO model and compares them with newer, updated versions in development. By comparing the results of newer simulations on past, well-known storms, she can verify if the updated model version will be more effective at predicting the track and intensity of future storms.

    “We are able to use cases like Hurricane Katrina to run tests and show us how we can improve, or how this new change affected the forecast or the analysis of the storm system,” Fuentes said.

    The closer the results are to the actual behavior of the storm, the more accurate the model.

    Fuentes has worked extensively on the intensity prediction of Hurricane Katrina. Weather models in 2005 – the year Katrina struck the Gulf Coast with devastating results – predicted that the storm’s pressure would reach as low as 955 millibars, significantly underestimating how low Katrina’s atmospheric pressure would get, and therefore the storm’s intensity. Observed data show that pressure in Hurricane Katrina’s eye reached a minimum of 902 millibars, one of the 10 lowest pressure readings on record for an Atlantic hurricane. The most modern model produced by the GMAO, which Fuentes has been analyzing, can produce a model of Katrina’s pressure much closer to the actual observed levels from 2005.

    Changes to these predictions are caused by improvements in data assimilation and model resolution, made possible by increased computer processing power. Improving the resolution of the model works similarly to increasing the resolution of a photo. The more pixels, or dots of color, in a square inch of a photo, the higher the resolution. High-resolution photos appear sharper and capture more detail than their low-resolution counterparts. Likewise, higher-resolution models produce more detailed simulations of hurricanes, giving researchers a better understanding of their behavior.

    “In the model we basically transform Earth’s atmosphere into little ‘cubes’ and in each cube the fundamental equations controlling motion, energy and continuity of the atmosphere are solved,” Reale said. “The smaller the size of the cube, the more realistic the representation of the atmosphere.”

    Reale said that high model resolution is a critical factor in capturing hurricanes accurately. Luckily, there has been much improvement to model resolution in the past 10 years.

    In 2005, the record year of 27 named tropical storms or hurricanes in the Atlantic, the size of the “cubes” in GMAO’s model was about 31 miles (50 km). Today, the resolution is three to four times higher at about 8 miles (12.5 km), giving scientists a much clearer and more detailed look at the state of the atmosphere.

    Of course, Reale said, there’s still work to be done. “There’s no such thing as perfect in research and science, but there is certainly a big improvement for the intensity that contemporary models could predict if they had to face a situation like that again,” he said.

    Reale believes this is the team to do it. “I feel that I’m part of an organization that is extremely successful in facing many different aspects of science,” he said. “There are people from all over the world, and I’m sure that whatever question or issue I may have, there’s someone who knows the answer in this building. I can tap into the knowledge and experience of so many people.”

    Fuentes and Reale are part of the GMAO, which consists of more than 150 people, all working on different aspects of the Earth-atmosphere-ocean-ice system. NASA collaborates closely with the National Oceanic and Atmospheric Administration, the agency that releases official forecasts to the public, to improve our understanding of hurricanes. Reale is also the principal investigator on a funded NASA project to improve hurricane intensity prediction through a better use of data from the Atmospheric Infrared Sounder (AIRS) onboard the NASA Aqua satellite.

    Related links:

    Since Katrina: NASA Advances Storm Models, Science
    Global Modeling and Assimilation Office

    See the full article here.

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    NASA’s Goddard Space Flight Center is home to the nation’s largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe.

    Named for American rocketry pioneer Dr. Robert H. Goddard, the center was established in 1959 as NASA’s first space flight complex. Goddard and its several facilities are critical in carrying out NASA’s missions of space exploration and scientific discovery.

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  • richardmitnick 4:54 pm on May 24, 2016 Permalink | Reply
    Tags: , , , , , NASA Goddard   

    From Goddard: “NASA Scientist Suggests Possible Link Between Primordial Black Holes and Dark Matter” 

    NASA Goddard Banner

    NASA Goddard Space Flight Center

    May 24, 2016
    Francis Reddy
    NASA’s Goddard Space Flight Center, Greenbelt, Maryland

    Dark matter is a mysterious substance composing most of the material universe, now widely thought to be some form of massive exotic particle. An intriguing alternative view is that dark matter is made of black holes formed during the first second of our universe’s existence, known as primordial black holes. Now a scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, suggests that this interpretation aligns with our knowledge of cosmic infrared and X-ray background glows and may explain the unexpectedly high masses of merging black holes detected last year.

    “This study is an effort to bring together a broad set of ideas and observations to test how well they fit, and the fit is surprisingly good,” said Alexander Kashlinsky, an astrophysicist at NASA Goddard. “If this is correct, then all galaxies, including our own, are embedded within a vast sphere of black holes each about 30 times the sun’s mass.”

    In 2005, Kashlinsky led a team of astronomers using NASA’s Spitzer Space Telescope to explore the background glow of infrared light in one part of the sky.

    NASA/Spitzer Telescope
    NASA/Spitzer Telescope

    The researchers reported excessive patchiness in the glow and concluded it was likely caused by the aggregate light of the first sources to illuminate the universe more than 13 billion years ago. Follow-up studies confirmed that this cosmic infrared background (CIB) showed similar unexpected structure in other parts of the sky.

    Cosmic Infrared Background, Credit: Michael Hauser (Space Telescope Science Institute), the COBE/DIRBE Science Team, and NASA)
    Cosmic Infrared Background, Credit: Michael Hauser (Space Telescope Science Institute), the COBE/DIRBE Science Team, and NASA)

    3
    After masking out all known stars, galaxies and artifacts and enhancing what’s left, an irregular background glow appears. This is the cosmic infrared background (CIB); lighter colors indicate brighter areas.

    4
    This image from NASA’s Spitzer Space Telescope shows an infrared view of a sky area in the constellation Ursa Major.

    The CIB glow is more irregular than can be explained by distant unresolved galaxies, and this excess structure is thought to be light emitted when the universe was less than a billion years old. Scientists say it likely originated from the first luminous objects to form in the universe, which includes both the first stars and black holes.

    In 2013, another study compared how the cosmic X-ray background (CXB) detected by NASA’s Chandra X-ray Observatory compared to the CIB in the same area of the sky.

    NASA/Chandra Telescope
    NASA/Chandra Telescope

    The first stars emitted mainly optical and ultraviolet light, which today is stretched into the infrared by the expansion of space, so they should not contribute significantly to the CXB.

    Yet the irregular glow of low-energy X-rays in the CXB matched the patchiness of the CIB quite well. The only object we know of that can be sufficiently luminous across this wide an energy range is a black hole. The research team concluded that primordial black holes must have been abundant among the earliest stars, making up at least about one out of every five of the sources contributing to the CIB.

    The nature of dark matter remains one of the most important unresolved issues in astrophysics. Scientists currently favor theoretical models that explain dark matter as an exotic massive particle, but so far searches have failed to turn up evidence these hypothetical particles actually exist. NASA is currently investigating this issue as part of its Alpha Magnetic Spectrometer and Fermi Gamma-ray Space Telescope missions.

    AMS-02 Bloc
    NASA/AMS02 device
    AMS02

    NASA/Fermi Telescope
    NASA/Fermi Telescope

    “These studies are providing increasingly sensitive results, slowly shrinking the box of parameters where dark matter particles can hide,” Kashlinsky said. “The failure to find them has led to renewed interest in studying how well primordial black holes — black holes formed in the universe’s first fraction of a second — could work as dark matter.”

    Physicists have outlined* several ways in which the hot, rapidly expanding universe could produce primordial black holes in the first thousandths of a second after the Big Bang. The older the universe is when these mechanisms take hold, the larger the black holes can be. And because the window for creating them lasts only a tiny fraction of the first second, scientists expect primordial black holes would exhibit a narrow range of masses.

    On Sept. 14, gravitational waves produced by a pair of merging black holes 1.3 billion light-years away were captured by the Laser Interferometer Gravitational-Wave Observatory (LIGO) facilities in Hanford, Washington, and Livingston, Louisiana.

    Caltech/MIT  Advanced Ligo Hanford, WA, USA installation
    Caltech/MIT Advanced Ligo Hanford, WA, USA installation

    Caltech/MIT Advanced aLigo detector in Livingston, Louisiana
    Caltech/MIT Advanced aLigo detector in Livingston, LA, USA

    This event marked the first-ever detection of gravitational waves as well as the first direct detection of black holes.


    Primordial black holes, if they exist, could be similar to the merging black holes detected by the LIGO team in 2014. This computer simulation shows in slow motion what this merger would have looked like up close. The ring around the black holes, called an Einstein ring, arises from all the stars in a small region directly behind the holes whose light is distorted by gravitational lensing. The gravitational waves detected by LIGO are not shown in this video, although their effects can be seen in the Einstein ring. Gravitational waves traveling out behind the black holes disturb stellar images comprising the Einstein ring, causing them to slosh around in the ring even long after the merger is complete. Gravitational waves traveling in other directions cause weaker, shorter-lived sloshing everywhere outside the Einstein ring. If played back in real time, the movie would last about a third of a second.
    Credits: SXS Lensing
    Access mp4 video here .

    The signal provided LIGO scientists with information about the masses of the individual black holes, which were 29 and 36 times the sun’s mass, plus or minus about four solar masses. These values were both unexpectedly large and surprisingly similar.

    In his new paper**, published May 24 in The Astrophysical Journal Letters, Kashlinsky analyzes what might have happened if dark matter consisted of a population of black holes similar to those detected by LIGO. The black holes distort the distribution of mass in the early universe, adding a small fluctuation that has consequences hundreds of millions of years later, when the first stars begin to form.

    For much of the universe’s first 500 million years, normal matter remained too hot to coalesce into the first stars. Dark matter was unaffected by the high temperature because, whatever its nature, it primarily interacts through gravity. Aggregating by mutual attraction, dark matter first collapsed into clumps called minihaloes, which provided a gravitational seed enabling normal matter to accumulate. Hot gas collapsed toward the minihaloes, resulting in pockets of gas dense enough to further collapse on their own into the first stars. Kashlinsky shows that if black holes play the part of dark matter, this process occurs more rapidly and easily produces the lumpiness of the CIB detected in Spitzer data even if only a small fraction of minihaloes manage to produce stars.

    As cosmic gas fell into the minihaloes, their constituent black holes would naturally capture some of it too. Matter falling toward a black hole heats up and ultimately produces X-rays. Together, infrared light from the first stars and X-rays from gas falling into dark matter black holes can account for the observed agreement between the patchiness of the CIB and the CXB.

    Occasionally, some primordial black holes will pass close enough to be gravitationally captured into binary systems. The black holes in each of these binaries will, over eons, emit gravitational radiation, lose orbital energy and spiral inward, ultimately merging into a larger black hole like the event LIGO observed.

    “Future LIGO observing runs will tell us much more about the universe’s population of black holes, and it won’t be long before we’ll know if the scenario I outline is either supported or ruled out,” Kashlinsky said.

    Kashlinsky leads science team centered at Goddard that is participating in the European Space Agency’s Euclid mission, which is currently scheduled to launch in 2020.

    ESA/Euclid spacecraft
    ESA/Euclid spacecraft

    The project, named LIBRAE, will enable the observatory to probe source populations in the CIB with high precision and determine what portion was produced by black holes.

    *Science paper:
    Primordial Black Holes – Recent Developments

    **Science paper:
    LIGO GRAVITATIONAL WAVE DETECTION, PRIMORDIAL BLACK HOLES, AND THE NEAR-IR COSMIC INFRARED BACKGROUND ANISOTROPIES

    See the full article here.

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    NASA’s Goddard Space Flight Center is home to the nation’s largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe.

    Named for American rocketry pioneer Dr. Robert H. Goddard, the center was established in 1959 as NASA’s first space flight complex. Goddard and its several facilities are critical in carrying out NASA’s missions of space exploration and scientific discovery.

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  • richardmitnick 5:32 pm on May 23, 2016 Permalink | Reply
    Tags: , , NASA Goddard,   

    From Goddard: “NASA: Solar Storms May Have Been Key to Life on Earth” 

    NASA Goddard Banner

    NASA Goddard Space Flight Center

    May 23, 2016
    Karen C. Fox
    NASA’s Goddard Space Flight Center, Greenbelt, Md.
    karen.c.fox@nasa.gov

    Solar eruption 2012 by NASA's Solar Dynamic Observatory SDO
    Solar eruption 2012 by NASA’s Solar Dynamic Observatory SDO

    Our sun’s adolescence was stormy—and new evidence shows that these tempests may have been just the key to seeding life as we know it.

    Some 4 billion years ago, the sun shone with only about three-quarters the brightness we see today, but its surface roiled with giant eruptions spewing enormous amounts of solar material and radiation out into space. These powerful solar explosions may have provided the crucial energy needed to warm Earth, despite the sun’s faintness. The eruptions also may have furnished the energy needed to turn simple molecules into the complex molecules such as RNA and DNA that were necessary for life. The research was published* in Nature Geoscience on May 23, 2016, by a team of scientists from NASA.


    Access mp4 video here .

    Understanding what conditions were necessary for life on our planet helps us both trace the origins of life on Earth and guide the search for life on other planets. Until now, however, fully mapping Earth’s evolution has been hindered by the simple fact that the young sun wasn’t luminous enough to warm Earth.

    “Back then, Earth received only about 70 percent of the energy from the sun than it does today,” said Vladimir Airapetian, lead author of the paper and a solar scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “That means Earth should have been an icy ball. Instead, geological evidence says it was a warm globe with liquid water. We call this the Faint Young Sun Paradox. Our new research shows that solar storms could have been central to warming Earth.”

    Scientists are able to piece together the history of the sun by searching for similar stars in our galaxy. By placing these sun-like stars in order according to their age, the stars appear as a functional timeline of how our own sun evolved. It is from this kind of data that scientists know the sun was fainter 4 billion years ago. Such studies also show that young stars frequently produce powerful flares – giant bursts of light and radiation — similar to the flares we see on our own sun today. Such flares are often accompanied by huge clouds of solar material, called coronal mass ejections, or CMEs, which erupt out into space.

    NASA’s Kepler mission found stars that resemble our sun about a few million years after its birth.

    NASA/Kepler Telescope
    NASA/Kepler Telescope

    The Kepler data showed many examples of what are called “superflares” – enormous explosions so rare today that we only experience them once every 100 years or so. Yet the Kepler data also show these youngsters producing as many as ten superflares a day.

    While our sun still produces flares and CMEs, they are not so frequent or intense.

    What’s more, Earth today has a strong magnetic field that helps keep the bulk of the energy from such space weather from reaching Earth.

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

    Space weather can, however, significantly disturb a magnetic bubble around our planet, the magnetosphere, a phenomenon referred to as geomagnetic storms that can affect radio communications and our satellites in space. It also creates auroras – most often in a narrow region near the poles where Earth’s magnetic fields bow down to touch the planet.

    Our young Earth, however, had a weaker magnetic field, with a much wider footprint near the poles.

    “Our calculations show that you would have regularly seen auroras all the way down in South Carolina,” says Airapetian. “And as the particles from the space weather traveled down the magnetic field lines, they would have slammed into abundant nitrogen molecules in the atmosphere. Changing the atmosphere’s chemistry turns out to have made all the difference for life on Earth.”

    The atmosphere of early Earth was also different than it is now: Molecular nitrogen – that is, two nitrogen atoms bound together into a molecule – made up 90 percent of the atmosphere, compared to only 78 percent today. As energetic particles slammed into these nitrogen molecules, the impact broke them up into individual nitrogen atoms. They, in turn, collided with carbon dioxide, separating those molecules into carbon monoxide and oxygen.

    The free-floating nitrogen and oxygen combined into nitrous oxide, which is a powerful greenhouse gas. When it comes to warming the atmosphere, nitrous oxide is some 300 times more powerful than carbon dioxide. The teams’ calculations show that if the early atmosphere housed less than one percent as much nitrous oxide as it did carbon dioxide, it would warm the planet enough for liquid water to exist.

    This newly discovered constant influx of solar particles to early Earth may have done more than just warm the atmosphere, it may also have provided the energy needed to make complex chemicals. In a planet scattered evenly with simple molecules, it takes a huge amount of incoming energy to create the complex molecules such as RNA and DNA that eventually seeded life.

    While enough energy appears to be hugely important for a growing planet, too much would also be an issue — a constant chain of solar eruptions producing showers of particle radiation can be quite detrimental. Such an onslaught of magnetic clouds can rip off a planet’s atmosphere if the magnetosphere is too weak. Understanding these kinds of balances help scientists determine what kinds of stars and what kinds of planets could be hospitable for life.

    “We want to gather all this information together, how close a planet is to the star, how energetic the star is, how strong the planet’s magnetosphere is in order to help search for habitable planets around stars near our own and throughout the galaxy,” said William Danchi, principal investigator of the project at Goddard and a co-author on the paper. “This work includes scientists from many fields — those who study the sun, the stars, the planets, chemistry and biology. Working together we can create a robust description of what the early days of our home planet looked like – and where life might exist elsewhere.”

    For more information about the Kepler mission, visit:

    http://www.nasa.gov/kepler

    *Science paper:
    Prebiotic chemistry and atmospheric warming of early Earth by an active young Sun

    See the full article here.

    Please help promote STEM in your local schools.

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    NASA’s Goddard Space Flight Center is home to the nation’s largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe.

    Named for American rocketry pioneer Dr. Robert H. Goddard, the center was established in 1959 as NASA’s first space flight complex. Goddard and its several facilities are critical in carrying out NASA’s missions of space exploration and scientific discovery.

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