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  • richardmitnick 10:43 am on February 20, 2019 Permalink | Reply
    Tags: "Solar Tadpole-Like Jets Seen With NASA’S IRIS Add New Clue to Age-Old Mystery", , , , , NASA Goddard, , ,   

    From NASA Goddard Space Flight Center: “Solar Tadpole-Like Jets Seen With NASA’S IRIS Add New Clue to Age-Old Mystery” 

    NASA Goddard Banner
    From NASA Goddard Space Flight Center

    Feb. 19, 2019
    Mara Johnson-Groh
    mara.johnson-groh@nasa.gov
    NASA’s Goddard Space Flight Center, Greenbelt, Md.

    NASA IRIS spacecraft

    Scientists have discovered tadpole-shaped jets coming out of regions with intense magnetic fields on the Sun. Unlike those living on Earth, these “tadpoles” — formally called pseudo-shocks — are made entirely of plasma, the electrically conducting material made of charged particles that account for an estimated 99 percent of the observable universe. The discovery adds a new clue to one of the longest-standing mysteries in astrophysics.

    1
    Anmated images from IRIS show the tadpole-shaped jets containing pseudo-shocks streaking out from the Sun.
    Credits: Abhishek Srivastava IIT (BHU)/Joy Ng, NASA’s Goddard Space Flight Center

    For 150 years scientists have been trying to figure out why the wispy upper atmosphere of the Sun — the corona — is over 200 times hotter than the solar surface. This region, which extends millions of miles, somehow becomes superheated and continually releases highly charged particles, which race across the solar system at supersonic speeds.

    When those particles encounter Earth, they have the potential to harm satellites and astronauts, disrupt telecommunications, and even interfere with power grids during particularly strong events. Understanding how the corona gets so hot can ultimately help us understand the fundamental physics behind what drives these disruptions.

    In recent years, scientists have largely debated two possible explanations for coronal heating: nanoflares and electromagnetic waves. The nanoflare theory proposes bomb-like explosions, which release energy into the solar atmosphere. Siblings to the larger solar flares, they are expected to occur when magnetic field lines explosively reconnect, releasing a surge of hot, charged particles. An alternative theory suggests a type of electromagnetic wave called Alfvén waves might push charged particles into the atmosphere like an ocean wave pushing a surfer. Scientists now think the corona may be heated by a combination of phenomenon like these, instead of a single one alone.

    The new discovery of pseudo-shocks adds another player to that debate. Particularly, it may contribute heat to the corona during specific times, namely when the Sun is active, such as during solar maximums — the most active part of the Sun’s 11-year cycle marked by an increase in sunspots, solar flares and coronal mass ejections.

    The discovery of the solar tadpoles was somewhat fortuitous. When recently analyzing data from NASA’s Interface Region Imaging Spectrograph, or IRIS, scientists noticed unique elongated jets emerging from sunspots ­— cool, magnetically-active regions on the Sun’s surface — and rising 3,000 miles up into the inner corona. The jets, with bulky heads and rarefied tails, looked to the scientists like tadpoles swimming up through the Sun’s layers.

    “We were looking for waves and plasma ejecta, but instead, we noticed these dynamical pseudo-shocks, like disconnected plasma jets, that are not like real shocks but highly energetic to fulfill Sun’s radiative losses,” said Abhishek Srivastava, scientist at the Indian Institute of Technology (BHU) in Varanasi, India, and lead author on the new paper in Nature Astronomy.

    Using computer simulations matching the events, they determined these pseudo-shocks could carry enough energy and plasma to heat the inner corona.

    2
    Animated computer simulation shows how the pseudo-shock is ejected and becomes disconnected from the plasma below (green). Credits: Abhishek Srivastava IIT (BHU)/Joy Ng, NASA’s Goddard Space Flight Center

    The scientists believe the pseudo-shocks are ejected by magnetic reconnection — an explosive tangling of magnetic field lines, which often occurs in and around sunspots. The pseudo-shocks have only been observed around the rims of sunspots so far, but scientists expect they’ll be found in other highly magnetized regions as well.

    3
    The tadpole-shaped pseudo-shocks, shown in dashed white box, are ejected from highly magnetized regions on the solar surface. Credits: Abhishek Srivastava IIT (BHU)/Joy Ng, NASA’s Goddard Space Flight Center

    Over the past five years, IRIS has kept an eye on the Sun in its 10,000-plus orbits around Earth. It’s one of several in NASA’s Sun-staring fleet that have continually observed the Sun over the past two decades. Together, they are working to resolve the debate over coronal heating and solve other mysteries the Sun keeps.

    “From the beginning, the IRIS science investigation has focused on combining high-resolution observations of the solar atmosphere with numerical simulations that capture essential physical processes,” said Bart De Pontieu research scientist at Lockheed Martin Solar & Astrophysics Laboratory in Palo Alto, California. “This paper is a nice illustration of how such a coordinated approach can lead to new physical insights into what drives the dynamics of the solar atmosphere.”

    The newest member in NASA’s heliophysics fleet, Parker Solar Probe, may be able to provide some additional clues to the coronal heating mystery.

    NASA Parker Solar Probe Plus named to honor Pioneering Physicist Eugene Parker

    Launched in 2018, the spacecraft flies through the solar corona to trace how energy and heat move through the region and to explore what accelerates the solar wind as well as solar energetic particles. Looking at phenomena far above the region where pseudo-shocks are found, Parker Solar Probe’s investigation hopes to shed light on other heating mechanisms, like nanoflares and electromagnetic waves. This work will complement the research conducted with IRIS.

    “This new heating mechanism could be compared to the investigations that Parker Solar Probe will be doing,” said Aleida Higginson, deputy project scientist for Parker Solar Probe at Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland. “Together they could provide a comprehensive picture of coronal heating.”

    Related Links:

    Learn more about NASA’s IRIS Mission
    NASA’s Parker Solar Probe and the Curious Case of the Hot Corona
    Learn more about NASA’s Parker Solar Probe

    See the full article here.


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

    Please help promote STEM in your local schools.

    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

     
  • richardmitnick 8:16 pm on February 19, 2019 Permalink | Reply
    Tags: "Citizen Scientist Finds Ancient White Dwarf Star Encircled by Puzzling Rings", Astronomers suspect this could be the first known white dwarf with multiple dust rings, , , , , J0207 is about 3 billion years old based on a temperature just over 10500 degrees Fahrenheit (5800 degrees Celsius), NASA Goddard, Whatever process is feeding material into its rings must operate on billion-year timescales, White Dwarf LSPM J0207+3331 or J0207 for short   

    From NASA Goddard Space Flight Center: “Citizen Scientist Finds Ancient White Dwarf Star Encircled by Puzzling Rings” 

    NASA Goddard Banner
    From NASA Goddard Space Flight Center

    Feb. 19, 2019
    Jeanette Kazmierczak
    jeanette.a.kazmierczak@nasa.gov
    NASA’s Goddard Space Flight Center, Greenbelt, Md.

    A volunteer working with the NASA-led Backyard Worlds: Planet 9 project has found the oldest and coldest known white dwarf — an Earth-sized remnant of a Sun-like star that has died — ringed by dust and debris. Astronomers suspect this could be the first known white dwarf with multiple dust rings.

    The star, LSPM J0207+3331 or J0207 for short, is forcing researchers to reconsider models of planetary systems and could help us learn about the distant future of our solar system.

    “This white dwarf is so old that whatever process is feeding material into its rings must operate on billion-year timescales,” said John Debes, an astronomer at the Space Telescope Science Institute in Baltimore. “Most of the models scientists have created to explain rings around white dwarfs only work well up to around 100 million years, so this star is really challenging our assumptions of how planetary systems evolve.”

    A paper detailing the findings, led by Debes, was published in the Feb. 19 issue of The Astrophysical Journal Letters.

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    In this illustration, an asteroid (bottom left) breaks apart under the powerful gravity of LSPM J0207+3331, the oldest, coldest white dwarf known to be surrounded by a ring of dusty debris. Scientists think the system’s infrared signal is best explained by two distinct rings composed of dust supplied by crumbling asteroids. Credits: NASA’s Goddard Space Flight Center/Scott Wiessinger.

    J0207 is located around 145 light-years away in the constellation Capricornus. White dwarfs slowly cool as they age, and Debes’ team calculated J0207 is about 3 billion years old based on a temperature just over 10,500 degrees Fahrenheit (5,800 degrees Celsius). A strong infrared signal picked up by NASA’s Wide-field Infrared Survey Explorer (WISE) mission — which mapped the entire sky in infrared light — suggested the presence of dust, making J0207 the oldest and coldest white dwarf with dust yet known.

    NASA Wise Telescope

    Previously, dust disks and rings had only been observed surrounding white dwarfs about one-third J0207’s age.

    When a Sun-like star runs out of fuel, it swells into a red giant, ejects at least half of its mass, and leaves behind a very hot white dwarf. Over the course of the star’s giant phase, planets and asteroids close to the star become engulfed and incinerated. Planets and asteroids farther away survive, but move outward as their orbits expand. That’s because when the star loses mass, its gravitational influence on surrounding objects is greatly reduced.

    This scenario describes the future of our solar system. Around 5 billion years from now, Mercury, then Venus and possibly Earth will be swallowed when the Sun grows into a red giant. Over hundreds of thousands to millions of years, the inner solar system will be scrubbed clean, and the remaining planets will drift outward.

    Yet some white dwarfs — between 1 and 4 percent — show infrared emission indicating they’re surrounded by dusty disks or rings. Scientists think the dust may arise from distant asteroids and comets kicked closer to the star by gravitational interactions with displaced planets. As these small bodies approach the white dwarf, the star’s strong gravity tears them apart in a process called tidal disruption. The debris forms a ring of dust that will slowly spiral down onto the surface of the star.

    J0207 was found through Backyard Worlds: Planet 9, a project led by Marc Kuchner, a co-author and astrophysicist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, that asks volunteers to sort through WISE data for new discoveries.

    Melina Thévenot, a co-author and citizen scientist in Germany working with the project, initially thought the infrared signal was bad data. She was searching through the ESA’s (European Space Agency’s) Gaia archives for brown dwarfs, objects too large to be planets and too small to be stars, when she noticed J0207. When she looked at the source in the WISE infrared data, it was too bright and too far away to be a brown dwarf. Thévenot passed her findings along to the Backyard Worlds: Planet 9 team. Debes and Kuchner contacted collaborator Adam Burgasser at the University of California, San Diego to obtain follow-up observations with the Keck II telescope at the W. M. Keck Observatory in Hawaii.

    Keck 2 telescope Maunakea Hawaii USA, 4,207 m (13,802 ft)

    “That is a really motivating aspect of the search,” said Thévenot, one of more than 150,000 citizen scientists on the Backyard Worlds project. “The researchers will move their telescopes to look at worlds you have discovered. What I especially enjoy, though, is the interaction with the awesome research team. Everyone is very kind, and they are always trying to make the best out of our discoveries.”

    The Keck observations helped confirm J0207’s record-setting properties. Now scientists are left to puzzle how it fits into their models.

    3
    Citizen scientists working on Backyard Worlds: Planet 9 scrutinize “flipbooks” of images from NASA’s Wide-field Infrared Survey Explorer. This animation shows a flipbook containing the ring-bearing white dwarf LSPM J0207+3331 (circled).
    Credits: Backyard Worlds: Planet 9/NASA’s Goddard Space Flight Center

    Debes compared the population of asteroid belt analogs in white dwarf systems to the grains of sand in an hourglass. Initially, there’s a steady stream of material. The planets fling asteroids inward towards the white dwarf to be torn apart, maintaining a dusty disk. But over time, the asteroid belts become depleted, just like grains of sand in the hourglass. Eventually, all the material in the disk falls down onto the surface of the white dwarf, so older white dwarfs like J0207 should be less likely to have disks or rings.

    J0207’s ring may even be multiple rings. Debes and his colleagues suggest there could be two distinct components, one thin ring just at the point where the star’s tides break up the asteroids and a wider ring closer to the white dwarf. Follow-up with future missions like NASA’s James Webb Space Telescope may help astronomers tease apart the ring’s constituent parts.

    “We built Backyard Worlds: Planet 9 mostly to search for brown dwarfs and new planets in the solar system,” Kuchner said. “But working with citizen scientists always leads to surprises. They are voracious — the project just celebrated its second birthday, and they’ve already discovered more than 1,000 likely brown dwarfs. Now that we’ve rebooted the website with double the amount of WISE data, we’re looking forward to even more exciting discoveries.”

    Backyard Worlds: Planet 9 is a collaboration between NASA, the American Museum of Natural History in New York, Arizona State University, National Optical Astronomy Observatory, the Space Telescope Science Institute in Baltimore, the University of California San Diego, Bucknell University, the University of Oklahoma, and Zooniverse, a collaboration of scientists, software developers and educators who collectively develop and manage citizen science projects on the internet.

    NASA’s Jet Propulsion Laboratory in Pasadena, California, manages and operates WISE for NASA’s Science Mission Directorate. The WISE mission was selected competitively under NASA’s Explorers Program managed by the agency’s Goddard Space Flight Center. The science instrument was built by the Space Dynamics Laboratory in Logan, Utah. The spacecraft was built by Ball Aerospace & Technologies Corp. in Boulder, Colorado. Placed in hibernation in 2011, the spacecraft was reactivated in 2013 and renamed NEOWISE. Science operations and data processing take place at the Infrared Processing and Analysis Center at Caltech, which manages JPL for NASA.

    For more information about Backyard Worlds: Planet 9, visit: http://backyardworlds.org

    For more information about NASA’s WISE mission, visit: http://www.nasa.gov/wise

    See the full article here.


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

    Please help promote STEM in your local schools.

    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

     
  • richardmitnick 5:46 pm on February 12, 2019 Permalink | Reply
    Tags: , , , , Earth's Radiation Belts, , NASA Goddard,   

    From NASA Goddard Space Flight Center: “NASA’s Van Allen Probes Begin Final Phase of Exploration in Earth’s Radiation Belts” 

    NASA Goddard Banner
    From NASA Goddard Space Flight Center

    Feb. 12, 2019

    Geoff Brown
    Johns Hopkins University Applied Physics Lab

    Media contact: Karen C. Fox
    NASA’s Goddard Space Flight Center, Greenbelt, Md.

    Two tough, resilient, NASA spacecraft have been orbiting Earth for the past six and a half years, flying repeatedly through a hazardous zone of charged particles around our planet called the Van Allen radiation belts. The twin Van Allen Probes, launched in August 2012, have confirmed scientific theories and revealed new structures and processes at work in these dynamic regions. Now, they’re starting a new and final phase in their exploration.

    Van Allen Radiation belts from ESA INTEGRAL

    Van Allen Belts NASA GSFC

    NASA Van Allen Probes

    On Feb. 12, 2019, one of the twin Van Allen Probes begins a series of orbit descent maneuvers to bring its lowest point of orbit, called perigee, just under 190 miles closer to Earth. This will bring the perigee from about 375 miles to about 190 miles — a change that will position the spacecraft for an eventual re-entry into Earth’s atmosphere about 15 years down the line.

    “In order for the Van Allen Probes to have a controlled re-entry within a reasonable amount of time, we need to lower the perigee,” said Nelli Mosavi, project manager for the Van Allen Probes at the Johns Hopkins Applied Physics Laboratory, or APL, in Laurel, Maryland. “At the new altitude, aerodynamic drag will bring down the satellites and eventually burn them up in the upper atmosphere. Our mission is to obtain great science data, and also to ensure that we prevent more space debris so the next generations have the opportunity to explore the space as well.”

    The other of the two Van Allen Probes will follow suit in March, also commanded by the mission operations team at APL, which designed and built the satellites.

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    The twin Van Allen Probes have spent more than six years orbiting through Earth’s radiation belts. Orbit changes in early 2019 will ensure that the spacecraft eventually de-orbit and disintegrate in Earth’s atmosphere. Credits: NASA Goddard’s Scientific Visualization Studio

    The Van Allen Probes spend most of their orbit within Earth’s radiation belts: doughnut-shaped bands of energized particles — protons and electrons — trapped in Earth’s magnetic field. These fast-moving particles create radiation that can interfere with satellite electronics and could even pose a threat to astronauts who pass through them on interplanetary journeys. The shape, size and intensity of the radiation belts changes in response to solar activity, which makes predicting their state difficult.

    Originally designated as a two-year mission — based on predictions that no spacecraft could operate much longer than that in the harsh radiation belts — these rugged spacecraft have operated without incident since 2012, and continue to enable groundbreaking discoveries about the Van Allen Belts.


    Credits: NASA’s Goddard Space Flight Center

    2
    After performing de-orbit maneuvers in February and March 2019, the Van Allen Probes’ highly elliptical orbits will gradually tighten over the next 15-25 years as the spacecraft experience atmospheric drag at perigee, the point in their orbits closest to Earth. This atmospheric drag will pull them into a circular orbit as early as 2034, at which point the spacecraft will begin to enter Earth’s atmosphere and safely disintegrate. Credits: Johns Hopkins APL

    “The Van Allen Probes mission has done a tremendous job in characterizing the radiation belts and providing us with the comprehensive information needed to deduce what is going on in them,” said David Sibeck, mission scientist for the Van Allen Probes at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “The very survival of these spacecraft and all their instruments, virtually unscathed, after all these years is an accomplishment and a lesson learned on how to design spacecraft.”

    Each spacecraft will be moved to a new, lower perigee of about 190 miles above Earth through a series of five two-hour engine burns. Because the Van Allen Probes spin while in orbit, the dates of these burns had to be chosen carefully. The needed geometry happens just once or twice per year: for spacecraft B, that period falls Feb. 12-22 of this year, and for spacecraft A, it’s March 11-22.

    The engine burns will each use about 4.4 pounds of propellant, leaving the spacecraft with enough fuel to keep their solar panels pointed at the Sun for about one more year.

    “We’ll continue to operate and obtain new science in our new orbit until we are out of fuel, at which point we won’t be able to point our solar panels at the Sun to power the spacecraft systems,” said Mosavi.

    During their last year or so of life, the Van Allen Probes will continue to gather data on Earth’s dynamic radiation belts. And their new, lower passes through Earth’s atmosphere will also provide new insight into how oxygen in Earth’s upper atmosphere can degrade satellite instruments — information that could help engineers design more resilient satellite instruments in the future.

    “The spacecraft and instruments have given us incredible insight into spacecraft operations in a high-radiation environment,” said Mosavi. “Everyone on the mission feels a real sense of pride and accomplishment in the work we’ve done and the science we’ve provided to the world — even as we begin the de-orbiting maneuvers.”

    Read more about what the Van Allen Probes have accomplished since 2012.

    For more on the Van Allen Probes: nasa.gov/vanallenprobes

    See the full article here.


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

    Please help promote STEM in your local schools.

    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

     
  • richardmitnick 2:25 pm on December 18, 2018 Permalink | Reply
    Tags: , , , , , NASA Goddard, Rings of Saturn   

    From NASA Goddard Space Flight Center: “NASA Research Reveals Saturn is Losing Its Rings at ‘Worst-Case-Scenario’ Rate” 

    NASA Goddard Banner
    From NASA Goddard Space Flight Center

    Dec. 17, 2018
    Bill Steigerwald
    william.a.steigerwald@nasa.gov

    Nancy Jones
    nancy.n.jones@nasa.gov

    NASA Goddard Space Flight Center, Greenbelt, Maryland

    New NASA research confirms that Saturn is losing its iconic rings at the maximum rate estimated from Voyager 1 & 2 observations made decades ago. The rings are being pulled into Saturn by gravity as a dusty rain of ice particles under the influence of Saturn’s magnetic field.


    This video explores how Saturn is losing its rings at a rapid rate in geologic timescales and what that reveals about the planet’s history.
    Credits: NASA’s Goddard Space Flight Center/David Ladd

    “We estimate that this ‘ring rain’ drains an amount of water products that could fill an Olympic-sized swimming pool from Saturn’s rings in half an hour,” said James O’Donoghue of NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “From this alone, the entire ring system will be gone in 300 million years, but add to this the Cassini-spacecraft measured ring-material detected falling into Saturn’s equator, and the rings have less than 100 million years to live. This is relatively short, compared to Saturn’s age of over 4 billion years.” O’Donoghue is lead author of a study on Saturn’s ring rain appearing in Icarus December 17.

    2
    This image was made as the Cassini spacecraft scanned across Saturn and its rings on April 25, 2016, capturing three sets of red, green and blue images to cover this entire scene showing the planet and the main rings. The images were obtained using Cassini’s wide-angle camera at a distance of approximately 1.9 million miles (3 million kilometers) from Saturn and at an elevation of about 30 degrees above the ring plane. Credits: NASA/JPL-Caltech/Space Science Institute.

    Scientists have long wondered if Saturn was formed with the rings or if the planet acquired them later in life. The new research favors the latter scenario, indicating that they are unlikely to be older than 100 million years, as it would take that long for the C-ring to become what it is today assuming it was once as dense as the B-ring. “We are lucky to be around to see Saturn’s ring system, which appears to be in the middle of its lifetime. However, if rings are temporary, perhaps we just missed out on seeing giant ring systems of Jupiter, Uranus and Neptune, which have only thin ringlets today!” O’Donoghue added.

    Various theories have been proposed for the ring’s origin. If the planet got them later in life, the rings could have formed when small, icy moons in orbit around Saturn collided, perhaps because their orbits were perturbed by a gravitational tug from a passing asteroid or comet.

    4
    An artist’s impression of how Saturn may look in the next hundred million years. The innermost rings disappear as they rain onto the planet first, very slowly followed by the outer rings. Credits: NASA/Cassini/James O’Donoghue

    The first hints that ring rain existed came from Voyager observations of seemingly unrelated phenomena: peculiar variations in Saturn’s electrically charged upper atmosphere (ionosphere), density variations in Saturn’s rings, and a trio of narrow dark bands encircling the planet at northern mid-latitudes. These dark bands appeared in images of Saturn’s hazy upper atmosphere (stratosphere) made by NASA’s Voyager 2 mission in 1981.

    In 1986, Jack Connerney of NASA Goddard published a paper in Geophysical Research Letters that linked those narrow dark bands to the shape of Saturn’s enormous magnetic field, proposing that electrically charged ice particles from Saturn’s rings were flowing down invisible magnetic field lines, dumping water in Saturn’s upper atmosphere where these lines emerged from the planet. The influx of water from the rings, appearing at specific latitudes, washed away the stratospheric haze, making it appear dark in reflected light, producing the narrow dark bands captured in the Voyager images.

    Saturn’s rings are mostly chunks of water ice ranging in size from microscopic dust grains to boulders several yards (meters) across. Ring particles are caught in a balancing act between the pull of Saturn’s gravity, which wants to draw them back into the planet, and their orbital velocity, which wants to fling them outward into space. Tiny particles can get electrically charged by ultraviolet light from the Sun or by plasma clouds emanating from micrometeoroid bombardment of the rings. When this happens, the particles can feel the pull of Saturn’s magnetic field, which curves inward toward the planet at Saturn’s rings. In some parts of the rings, once charged, the balance of forces on these tiny particles changes dramatically, and Saturn’s gravity pulls them in along the magnetic field lines into the upper atmosphere.

    Once there, the icy ring particles vaporize and the water can react chemically with Saturn’s ionosphere. One outcome from these reactions is an increase in the lifespan of electrically charged particles called H3+ ions, which are made up of three protons and two electrons. When energized by sunlight, the H3+ ions glow in infrared light, which was observed by O’Donoghue’s team using special instruments attached to the Keck telescope in Mauna Kea, Hawaii.


    Keck Observatory, Maunakea, Hawaii, USA.4,207 m (13,802 ft), above sea level,

    Their observations revealed glowing bands in Saturn’s northern and southern hemispheres where the magnetic field lines that intersect the ring plane enter the planet. They analyzed the light to determine the amount of rain from the ring and its effects on Saturn’s ionosphere. They found that the amount of rain matches remarkably well with the astonishingly high values derived more than three decades earlier by Connerney and colleagues, with one region in the south receiving most of it.

    The team also discovered a glowing band at a higher latitude in the southern hemisphere. This is where Saturn’s magnetic field intersects the orbit of Enceladus, a geologically active moon that is shooting geysers of water ice into space, indicating that some of those particles are raining onto Saturn as well. “That wasn’t a complete surprise,” said Connerney. “We identified Enceladus and the E-ring as a copious source of water as well, based on another narrow dark band in that old Voyager image.” The geysers, first observed by Cassini instruments in 2005, are thought to be coming from an ocean of liquid water beneath the frozen surface of the tiny moon. Its geologic activity and water ocean make Enceladus one of the most promising places to search for extraterrestrial life.

    3
    Saturn’s moon Enceladus drifts before the rings and the tiny moon Pandora in this view that NASA’s Cassini spacecraft captured on Nov. 1, 2009. The entire scene is backlit by the Sun, providing striking illumination for the icy particles that make up both the rings and the jets emanating from the south pole of Enceladus, which is about 314 miles (505 km) across. Pandora, which is about (52 miles, 84 kilometers) wide, was on the opposite side of the rings from Cassini and Enceladus when the image was taken. This view looks toward the night side on Pandora as well, which is lit by dim golden light reflected from Saturn.
    Credits: NASA/JPL-Caltech/Space Science Institute

    The team would like to see how the ring rain changes with the seasons on Saturn. As the planet progresses in its 29.4-year orbit, the rings are exposed to the Sun to varying degrees. Since ultraviolet light from the Sun charges the ice grains and makes them respond to Saturn’s magnetic field, varying exposure to sunlight should change the quantity of ring rain.

    The research was funded by NASA and the NASA Postdoctoral Program at NASA Goddard, administered by the Universities Space Research Association. The W.M. Keck Observatory is operated as a scientific partnership among the California Institute of Technology, the University of California, and NASA, and the data in the form of its files are available from the Keck archive. The authors wish to recognize the significant cultural role and reverence that the summit of Mauna Kea has within the indigenous Hawaiian community; they are fortunate to have the opportunity to conduct observations from this mountain.

    See the full article here.


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

    Please help promote STEM in your local schools.

    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

     
  • richardmitnick 9:07 am on November 6, 2018 Permalink | Reply
    Tags: , , , , , NASA Goddard, New Tricks: Fresh Results from NASA’s Galileo Spacecraft 20 Years On   

    From NASA Goddard Space Flight Center via Manu Garcia: “Fresh Results from NASA’s Galileo Spacecraft 20 Years On” 


    From Manu Garcia, a friend from IAC.

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

    NASA Goddard Banner
    From NASA Goddard Space Flight Center

    April 30, 2018
    Mara Johnson-Groh
    mara.johnson-groh@nasa.gov
    NASA’s Goddard Space Flight Center, Greenbelt, Md.

    NASA/Galileo 1989-2003

    Far across the solar system, from where Earth appears merely as a pale blue dot, NASA’s Galileo spacecraft spent eight years orbiting Jupiter. During that time, the hearty spacecraft — slightly larger than a full-grown giraffe — sent back spates of discoveries on the gas giant’s moons, including the observation of a magnetic environment around Ganymede that was distinct from Jupiter’s own magnetic field. The mission ended in 2003, but newly resurrected data from Galileo’s first flyby of Ganymede is yielding new insights about the moon’s environment — which is unlike any other in the solar system.

    “We are now coming back over 20 years later to take a new look at some of the data that was never published and finish the story,” said Glyn Collinson, lead author of a recent paper about Ganymede’s magnetosphere at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “We found there’s a whole piece no one knew about.”

    The new results showed a stormy scene: particles blasted off the moon’s icy surface as a result of incoming plasma rain, and strong flows of plasma pushed between Jupiter and Ganymede due to an explosive magnetic event occurring between the two bodies’ magnetic environments. Scientists think these observations could be key to unlocking the secrets of the moon, such as why Ganymede’s auroras are so bright.

    In 1996, shortly after arriving at Jupiter, Galileo made a surprising discovery: Ganymede had its own magnetic field.

    3
    Proposed magnetic field on Ganymede

    While most planets in our solar system, including Earth, have magnetic environments — known as magnetospheres — no one expected a moon to have one.

    2
    This image of Ganymede, one of Jupiter’s moons and the largest moon in our solar system, was taken by NASA’s Galileo spacecraft. Credits: NASA

    Between 1996 and 2000, Galileo made six targeted flybys of Ganymede, with multiple instruments collecting data on the moon’s magnetosphere. These included the spacecraft’s Plasma Subsystem, or PLS, which measured the density, temperature and direction of the plasma — excited, electrically charged gas — flowing through the environment around Galileo. New results, recently published in the journal Geophysical Research Letters, reveal interesting details about the magnetosphere’s unique structure.

    We know that Earth’s magnetosphere — in addition to helping make compasses work and causing auroras — is key to in sustaining life on our planet, because it helps protect our planet from radiation coming from space. Some scientists think Earth’s magnetosphere was also essential for the initial development of life, as this harmful radiation can erode our atmosphere. Studying magnetospheres throughout the solar system not only helps scientists learn about the physical processes affecting this magnetic environment around Earth, it helps us understand the atmospheres around other potentially habitable worlds, both in our own solar system and beyond.

    3
    This infographic describes Ganymede’s magnetosphere. Credits: NASA’s Goddard Space Flight Center/Mary Pat Hrybyk-Keith

    Ganymede’s magnetosphere offers the chance to explore a unique magnetic environment located within the much larger magnetosphere of Jupiter. Nestled there, it’s protected from the solar wind, making its shape different from other magnetospheres in the solar system. Typically, magnetospheres are shaped by the pressure of supersonic solar wind particles flowing past them. But at Ganymede, the relatively slower-moving plasma around Jupiter sculpts the moon’s magnetosphere into a long horn-like shape that stretches ahead of the moon in the direction of its orbit.

    Flying past Ganymede, Galileo was continually pummeled by high-energy particles — a battering the moon is also familiar with. Plasma particles accelerated by the Jovian magnetosphere, continually rain down on Ganymede’s poles, where the magnetic field channels them toward the surface. The new analysis of Galileo PLS data showed plasma being blasted off the moon’s icy surface due to the incoming plasma rain.

    “There are these particles flying out from the polar regions, and they can tell us something about Ganymede’s atmosphere, which is very thin,” said Bill Paterson, a co-author of the study at NASA Goddard, who served on the Galileo PLS team during the mission. “It can also tell us about how Ganymede’s auroras form.”


    This visualization shows a simplified model of Jupiter’s magnetosphere, designed to illustrate the scale, and basic features of the structure and impacts of the magnetic axis (cyan arrow) offset from the planetary rotation axis (blue arrow). The semi-transparent gray mesh in the distance represents the boundary of the magnetosphere.
    Credits: NASA’s Scientific Visualization Studio/JPL NAIF

    Ganymede has auroras, or northern and southern lights, just like Earth does. However, unlike our planet, the particles causing Ganymede’s auroras come from the plasma surrounding Jupiter, not the solar wind. When analyzing the data, the scientists noticed that during its first Ganymede flyby, Galileo fortuitously crossed right over Ganymede’s auroral regions, as evidenced by the ions it observed raining down onto the surface of the moon’s polar cap. By comparing the location where the falling ions were observed with data from Hubble, the scientists were able to pin down the precise location of the auroral zone, which will help them solve mysteries, such as what causes the auroras.

    As it cruised around Jupiter, Galileo also happened to fly right through an explosive event caused by the tangling and snapping of magnetic field lines. This event, called magnetic reconnection, occurs in magnetospheres across our solar system. For the first time, Galileo observed strong flows of plasma pushed between Jupiter and Ganymede due to a magnetic reconnection event occurring between the two magnetospheres. It’s thought that this plasma pump is responsible for making Ganymede’s auroras unusually bright.

    Future study of the PLS data from that encounter may yet provide new insights related to subsurface oceans previously determined to exist within the moon using data from both Galileo and the Hubble Space Telescope.

    The research was funded by NASA’s Solar System Workings program and the Galileo mission managed by NASA’s Jet Propulsion Laboratory in Pasadena, California, for the agency’s Science Mission Directorate in Washington.

    See the full article here.


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

    Please help promote STEM in your local schools.

    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

     
  • richardmitnick 1:09 pm on October 12, 2018 Permalink | Reply
    Tags: , , , , Dame Susan Jocelyn Bell Burnell discovered pulsars with radio astronomy at the Mullard Radio Astronomy Observatory Cambridge University-Denied the Nobel., NASA Goddard, ,   

    From NASA Goddard Space Flight Center: “‘Pulsar in a Box’ Reveals Surprising Picture of a Neutron Star’s Surroundings” 

    NASA Goddard Banner
    From NASA Goddard Space Flight Center

    Oct. 10, 2018
    Francis Reddy
    francis.j.reddy@nasa.gov
    NASA’s Goddard Space Flight Center, Greenbelt, Md.

    An international team of scientists studying what amounts to a computer-simulated “pulsar in a box” are gaining a more detailed understanding of the complex, high-energy environment around spinning neutron stars, also called pulsars.

    1
    ‘Pulsar in a Box’ Reveals Surprises in Neutron Star’s Surroundings | NASA


    Explore a new “pulsar in a box” computer simulation that tracks the fate of electrons (blue) and their antimatter kin, positrons (red), as they interact with powerful magnetic and electric fields around a neutron star. Lighter tracks indicate higher particle energies. Each particle seen in this visualization actually represents trillions of electrons or positrons. Better knowledge of the particle environment around neutron stars will help astronomers understand how they produce precisely timed radio and gamma-ray pulses.
    Credits: NASA’s Goddard Space Flight Center

    The model traces the paths of charged particles in magnetic and electric fields near the neutron star, revealing behaviors that may help explain how pulsars emit gamma-ray and radio pulses with ultraprecise timing.

    “Efforts to understand how pulsars do what they do began as soon as they were discovered in 1967, and we’re still working on it,” said Gabriele Brambilla, an astrophysicist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and the University of Milan who led a study of the recent simulation.

    Dame Susan Jocelyn Bell Burnell, discovered pulsars with radio astronomy. Jocelyn Bell at the Mullard Radio Astronomy Observatory, Cambridge University, taken for the Daily Herald newspaper in 1968. Denied the Nobel.

    Dame Susan Jocelyn Bell Burnell 2009

    “Even with the computational power available today, tracking the physics of particles in the extreme environment of a pulsar is a considerable challenge.”

    A pulsar is the crushed core of a massive star that ran out of fuel, collapsed under its own weight and exploded as a supernova. Gravity forces more mass than the Sun’s into a ball no wider than Manhattan Island in New York City while also revving up its rotation and strengthening its magnetic field. Pulsars can spin thousands of times a second and wield the strongest magnetic fields known.

    These characteristics also make pulsars powerful dynamos, with superstrong electric fields that can rip particles out of the surface and accelerate them into space.

    NASA’s Fermi Gamma-ray Space Telescope has detected gamma rays from 216 pulsars.

    NASA/Fermi LAT


    NASA/Fermi Gamma Ray Space Telescope

    Observations show that the high-energy emission occurs farther away from the neutron star than the radio pulses. But exactly where and how these signals are produced remains poorly known.

    Various physical processes ensure that most of the particles around a pulsar are either electrons or their antimatter counterparts, positrons.

    “Just a few hundred yards above a pulsar’s magnetic pole, electrons pulled from the surface may have energies comparable to those reached by the most powerful particle accelerators on Earth,” said Goddard’s Alice Harding. “In 2009, Fermi discovered powerful gamma-ray flares from the Crab Nebula pulsar that indicate the presence of electrons with energies a thousand times greater.”

    X-ray picture of Crab pulsar, taken by Chandra


    Supernova remnant Crab nebula. NASA/ESA Hubble

    Speedy electrons emit gamma rays, the highest-energy form of light, through a process called curvature radiation. A gamma-ray photon can, in turn, interact with the pulsar’s magnetic field in a way that transforms it into a pair of particles, an electron and a positron.

    To trace the behavior and energies of these particles, Brambilla, Harding and their colleagues used a comparatively new type of pulsar model called a “particle in cell” (PIC) simulation. Goddard’s Constantinos Kalapotharakos led the development of the project’s computer code. In the last five years, the PIC method has been applied to similar astrophysical settings by teams at Princeton University in New Jersey and Columbia University in New York.

    “The PIC technique lets us explore the pulsar from first principles. We start with a spinning, magnetized pulsar, inject electrons and positrons at the surface, and track how they interact with the fields and where they go,” Kalapotharakos said. “The process is computationally intensive because the particle motions affect the electric and magnetic fields and the fields affect the particles, and everything is moving near the speed of light.”

    The simulation shows that most of the electrons tend to race outward from the magnetic poles. The positrons, on the other hand, mostly flow out at lower latitudes, forming a relatively thin structure called the current sheet. In fact, the highest-energy positrons here — less than 0.1 percent of the total — are capable of producing gamma rays similar to those Fermi detects, confirming the results of earlier studies.

    Some of these particles likely become boosted to tremendous energies at points within the current sheet where the magnetic field undergoes reconnection, a process that converts stored magnetic energy into heat and particle acceleration.

    One population of medium-energy electrons showed truly odd behavior, scattering every which way — even back toward the pulsar.

    The particles move with the magnetic field, which sweeps back and extends outward as the pulsar spins. Their rotational speed rises with increasing distance, but this can only go on so long because matter can’t travel at the speed of light.

    The distance where the plasma’s rotational velocity would reach light speed is a feature astronomers call the light cylinder, and it marks a region of abrupt change. As the electrons approach it, they suddenly slow down and many scatter wildly. Others can slip past the light cylinder and out into space.

    The simulation ran on the Discover supercomputer at NASA’s Center for Climate Simulation at Goddard and the Pleiades supercomputer at NASA’s Ames Research Center in Silicon Valley, California.

    NASA Discover SGI Supercomputer- NASA’s Center for Climate Simulation Primary Computing Platform

    NASA SGI Intel Advanced Supercomputing Center Pleiades Supercomputer

    The model actually tracks “macroparticles,” each of which represents many trillions of electrons or positrons. A paper describing the findings was published May 9 in The Astrophysical Journal

    “So far, we lack a comprehensive theory to explain all the observations we have from neutron stars. That tells us we don’t yet completely understand the origin, acceleration and other properties of the plasma environment around the pulsar,” Brambilla said. “As PIC simulations grow in complexity, we can expect a clearer picture.”

    NASA’s Fermi Gamma-ray Space Telescope is an astrophysics and particle physics partnership, developed in collaboration with the U.S. Department of Energy and with important contributions from academic institutions and partners in France, Germany, Italy, Japan, Sweden and the United States.

    For more about NASA’s Fermi mission, visit:

    https://www.nasa.gov/fermi.

    See the full article here.

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

    Please help promote STEM in your local schools.

    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

     
  • richardmitnick 8:37 am on October 4, 2018 Permalink | Reply
    Tags: , Blue Waters supercomputer at the University of Illinois at Urbana-Champaign, , , NASA Goddard,   

    From NASA Goddard Space Flight Center via Manu Garcia of IAC: “New Simulation Sheds Light on Spiraling Supermassive Black Holes” 


    From Manu Garcia, a friend from IAC.

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

    NASA Goddard Banner
    From NASA Goddard Space Flight Center

    Oct. 2, 2018
    Jeanette Kazmierczak
    jeanette.a.kazmierczak@nasa.gov
    NASA’s Goddard Space Flight Center, Greenbelt, Md.

    1
    This animation rotates 360 degrees around a frozen version of the simulation in the plane of the disk. Credit: NASA’s Goddard Space Flight Center

    A new model is bringing scientists a step closer to understanding the kinds of light signals produced when two supermassive black holes, which are millions to billions of times the mass of the Sun, spiral toward a collision. For the first time, a new computer simulation that fully incorporates the physical effects of Einstein’s general theory of relativity shows that gas in such systems will glow predominantly in ultraviolet and X-ray light.

    Just about every galaxy the size of our own Milky Way or larger contains a monster black hole at its center. Observations show galaxy mergers occur frequently in the universe, but so far no one has seen a merger of these giant black holes.

    “We know galaxies with central supermassive black holes combine all the time in the universe, yet we only see a small fraction of galaxies with two of them near their centers,” said Scott Noble, an astrophysicist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “The pairs we do see aren’t emitting strong gravitational-wave signals because they’re too far away from each other. Our goal is to identify — with light alone — even closer pairs from which gravitational-wave signals may be detected in the future.”

    A paper describing the team’s analysis of the new simulation was published Tuesday, Oct. 2, in The Astrophysical Journal.


    Gas glows brightly in this computer simulation of supermassive black holes only 40 orbits from merging. Models like this may eventually help scientists pinpoint real examples of these powerful binary systems. Credits: NASA’s Goddard Space Flight Center

    Scientists have detected merging stellar-mass black holes — which range from around three to several dozen solar masses — using the National Science Foundation’s Laser Interferometer Gravitational-Wave Observatory (LIGO).

    Gravitational waves are space-time ripples traveling at the speed of light. They are created when massive orbiting objects like black holes and neutron stars spiral together and merge.

    Black holes heading toward a merger. Precise laser interferometry can detect the ripples in space-time generated when two black holes collide. LIGO-Caltech-MIT-Sonoma State Aurore Simonn

    Cornell SXS, the Simulating eXtreme Spacetimes (SXS) project

    Supermassive mergers will be much more difficult to find than their stellar-mass cousins. One reason ground-based observatories can’t detect gravitational waves from these events is because Earth itself is too noisy, shaking from seismic vibrations and gravitational changes from atmospheric disturbances. The detectors must be in space, like the Laser Interferometer Space Antenna (LISA) led by ESA (the European Space Agency) and planned for launch in the 2030s.


    ESA/NASA eLISA space based, the future of gravitational wave research

    Observatories monitoring sets of rapidly spinning, superdense stars called pulsars may detect gravitational waves from monster mergers. Like lighthouses, pulsars emit regularly timed beams of light that flash in and out of view as they rotate. Gravitational waves could cause slight changes in the timing of those flashes, but so far studies haven’t yielded any detections.

    But supermassive binaries nearing collision may have one thing stellar-mass binaries lack — a gas-rich environment. Scientists suspect the supernova explosion that creates a stellar black hole also blows away most of the surrounding gas. The black hole consumes what little remains so quickly there isn’t much left to glow when the merger happens.

    Supermassive binaries, on the other hand, result from galaxy mergers. Each supersized black hole brings along an entourage of gas and dust clouds, stars and planets. Scientists think a galaxy collision propels much of this material toward the central black holes, which consume it on a time scale similar to that needed for the binary to merge. As the black holes near, magnetic and gravitational forces heat the remaining gas, producing light astronomers should be able to see.

    “It’s very important to proceed on two tracks,” said co-author Manuela Campanelli, director of the Center for Computational Relativity and Gravitation at the Rochester Institute of Technology in New York, who initiated this project nine years ago. “Modeling these events requires sophisticated computational tools that include all the physical effects produced by two supermassive black holes orbiting each other at a fraction of the speed of light. Knowing what light signals to expect from these events will help modern observations identify them. Modeling and observations will then feed into each other, helping us better understand what is happening at the hearts of most galaxies.”

    The new simulation shows three orbits of a pair of supermassive black holes only 40 orbits from merging. The models reveal the light emitted at this stage of the process may be dominated by UV light with some high-energy X-rays, similar to what’s seen in any galaxy with a well-fed supermassive black hole.

    Three regions of light-emitting gas glow as the black holes merge, all connected by streams of hot gas: a large ring encircling the entire system, called the circumbinary disk, and two smaller ones around each black hole, called mini disks. All these objects emit predominantly UV light. When gas flows into a mini disk at a high rate, the disk’s UV light interacts with each black hole’s corona, a region of high-energy subatomic particles above and below the disk. This interaction produces X-rays. When the accretion rate is lower, UV light dims relative to the X-rays.

    Based on the simulation, the researchers expect X-rays emitted by a near-merger will be brighter and more variable than X-rays seen from single supermassive black holes. The pace of the changes links to both the orbital speed of gas located at the inner edge of the circumbinary disk as well as that of the merging black holes.


    This 360-degree video places the viewer in the middle of two circling supermassive black holes around 18.6 million miles (30 million kilometers) apart with an orbital period of 46 minutes. The simulation shows how the black holes distort the starry background and capture light, producing black hole silhouettes. A distinctive feature called a photon ring outlines the black holes. The entire system would have around 1 million times the Sun’s mass. Credits: NASA’s Goddard Space Flight Center; background, ESA/Gaia/DPAC

    “The way both black holes deflect light gives rise to complex lensing effects, as seen in the movie when one black hole passes in front of the other,” said Stéphane d’Ascoli, a doctoral student at École Normale Supérieure in Paris and lead author of the paper. “Some exotic features came as a surprise, such as the eyebrow-shaped shadows one black hole occasionally creates near the horizon of the other.”

    The simulation ran on the National Center for Supercomputing Applications’ Blue Waters supercomputer at the University of Illinois at Urbana-Champaign.

    U Illinois Urbana-Champaign Blue Waters Cray Linux XE/XK hybrid machine supercomputer

    Modeling three orbits of the system took 46 days on 9,600 computing cores. Campanelli said the collaboration was recently awarded additional time on Blue Waters to continue developing their models.

    The original simulation estimated gas temperatures. The team plans to refine their code to model how changing parameters of the system, like temperature, distance, total mass and accretion rate, will affect the emitted light. They’re interested in seeing what happens to gas traveling between the two black holes as well as modeling longer time spans.

    “We need to find signals in the light from supermassive black hole binaries distinctive enough that astronomers can find these rare systems among the throng of bright single supermassive black holes,” said co-author Julian Krolik, an astrophysicist at Johns Hopkins University in Baltimore. “If we can do that, we might be able to discover merging supermassive black holes before they’re seen by a space-based gravitational-wave observatory.”

    See the full article here.


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

    Please help promote STEM in your local schools.

    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

     
  • richardmitnick 1:02 pm on August 7, 2018 Permalink | Reply
    Tags: , , , , , NASA Goddard, , NASA’s Planet-Hunting TESS Catches a Comet Before Starting Science   

    From NASA Goddard Space Flight Center: “NASA’s Planet-Hunting TESS Catches a Comet Before Starting Science” 

    NASA Goddard Banner
    From NASA Goddard Space Flight Center

    THIS POST IS DEDICATED TO JLT in L.A., a fan of JPL who really ought to be thinking about Goddard as he plans his future. Goddard would mean either John’s Hopkins for the Applied Physics Lab or of course M.I.T.

    Aug. 6, 2018
    Claire Saravia
    claire.g.desaravia@nasa.gov
    NASA’s Goddard Space Flight Center, Greenbelt, Md.

    NASA/MIT TESS

    Before NASA’s Transiting Exoplanet Survey Satellite (TESS) started science operations on July 25, 2018, the planet hunter sent back a stunning sequence of serendipitous images showing the motion of a comet. Taken over the course of 17 hours on July 25, these TESS images helped demonstrate the satellite’s ability to collect a prolonged set of stable periodic images covering a broad region of the sky — all critical factors in finding transiting planets orbiting nearby stars.

    Over the course of these tests, TESS took images of C/2018 N1, a comet discovered by NASA’s Near-Earth Object Wide-field Infrared Survey Explorer (NEOWISE) satellite on June 29. The comet, located about 29 million miles (48 million kilometers) from Earth in the southern constellation Piscis Austrinus, is seen to move across the frame from right to left as it orbits the Sun. The comet’s tail, which consists of gases carried away from the comet by an outflow from the Sun called the solar wind, extends to the top of the frame and gradually pivots as the comet glides across the field of view.


    This video is compiled from a series of images taken on July 25 by the Transiting Exoplanet Survey Satellite. The angular extent of the widest field of view is six degrees. Visible in the images are the comet C/2018 N1, asteroids, variable stars, asteroids and reflected light from Mars. TESS is expected to find thousands of planets around other nearby stars.
    Credits: Massachusetts Institute of Technology/NASA’s Goddard Space Flight Center

    In addition to the comet, the images reveal a treasure trove of other astronomical activity. The stars appear to shift between white and black as a result of image processing. The shift also highlights variable stars — which change brightness either as a result of pulsation, rapid rotation, or by eclipsing binary neighbors. Asteroids in our solar system appear as small white dots moving across the field of view. Towards the end of the video, one can see a faint broad arc of light moving across the middle section of the frame from left to right. This is stray light from Mars, which is located outside the frame. The images were taken when Mars was at its brightest near opposition, or its closest distance, to Earth.

    These images were taken during a short period near the end of the mission’s commissioning phase, prior to the start of science operations. The movie presents just a small fraction of TESS’s active field of view. The team continues to fine-tune the spacecraft’s performance as it searches for distant worlds.

    TESS is a NASA Astrophysics Explorer mission led and operated by MIT in Cambridge, Massachusetts, and managed by NASA’s Goddard Space Flight Center in Greenbelt, Maryland. Dr. George Ricker of MIT’s Kavli Institute for Astrophysics and Space Research serves as principal investigator for the mission. Additional partners include Northrop Grumman, based in Falls Church, Virginia; NASA’s Ames Research Center in California’s Silicon Valley; the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts; MIT’s Lincoln Laboratory in Lexington, Massachusetts; and the Space Telescope Science Institute in Baltimore. More than a dozen universities, research institutes and observatories worldwide are participants in the mission.

    Johns Hopkins Applied Physics Lab Campus

    See the full article here.


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

    Please help promote STEM in your local schools.

    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

     
  • richardmitnick 8:10 pm on July 3, 2018 Permalink | Reply
    Tags: , , , , , NASA Goddard, , NASA's NuSTAR Mission Proves Superstar Eta Carinae Shoots Cosmic Rays   

    From NASA Goddard Space Flight Center: “NASA’s NuSTAR Mission Proves Superstar Eta Carinae Shoots Cosmic Rays” 

    NASA Goddard Banner
    From NASA Goddard Space Flight Center

    July 3, 2018
    Francis Reddy
    francis.j.reddy@nasa.gov
    NASA’s Goddard Space Flight Center, Greenbelt, Md.

    A new study using data from NASA’s NuSTAR space telescope suggests that Eta Carinae, the most luminous and massive stellar system within 10,000 light-years, is accelerating particles to high energies — some of which may reach Earth as cosmic rays.

    NASA NuSTAR X-ray telescope

    Eta Carinae Image Credit: N. Smith, J. A. Morse (U. Colorado) et al., NASA

    “We know the blast waves of exploded stars can accelerate cosmic ray particles to speeds comparable to that of light, an incredible energy boost,” said Kenji Hamaguchi, an astrophysicist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and the lead author of the study. “Similar processes must occur in other extreme environments. Our analysis indicates Eta Carinae is one of them.”

    Astronomers know that cosmic rays with energies greater than 1 billion electron volts (eV) come to us from beyond our solar system. But because these particles — electrons, protons and atomic nuclei — all carry an electrical charge, they veer off course whenever they encounter magnetic fields. This scrambles their paths and masks their origins.


    Zoom into Eta Carinae, where the outflows of two massive stars collide and shoot accelerated particles — cosmic rays — into space.
    Credits: NASA’s Goddard Space Flight Center

    Eta Carinae, located about 7,500 light-years away in the southern constellation of Carina, is famous for a 19th century outburst that briefly made it the second-brightest star in the sky. This event also ejected a massive hourglass-shaped nebula, but the cause of the eruption remains poorly understood.

    The system contains a pair of massive stars whose eccentric orbits bring them unusually close every 5.5 years. The stars contain 90 and 30 times the mass of our Sun and pass 140 million miles (225 million kilometers) apart at their closest approach — about the average distance separating Mars and the Sun.

    “Both of Eta Carinae’s stars drive powerful outflows called stellar winds,” said team member Michael Corcoran, also at Goddard. “Where these winds clash changes during the orbital cycle, which produces a periodic signal in low-energy X-rays we’ve been tracking for more than two decades.”

    NASA’s Fermi Gamma-ray Space Telescope also observes a change in gamma rays — light packing far more energy than X-rays — from a source in the direction of Eta Carinae. But Fermi’s vision isn’t as sharp as X-ray telescopes, so astronomers couldn’t confirm the connection.

    1
    Eta Carinae shines in X-rays in this image from NASA’s Chandra X-ray Observatory.

    NASA/Chandra X-ray Telescope

    The colors indicate different energies. Red spans 300 to 1,000 electron volts (eV), green ranges from 1,000 to 3,000 eV and blue covers 3,000 to 10,000 eV. For comparison, the energy of visible light is about 2 to 3 eV. NuSTAR observations (green contours) reveal a source of X-rays with energies some three times higher than Chandra detects. X-rays seen from the central point source arise from the binary’s stellar wind collision. The NuSTAR detection shows that shock waves in the wind collision zone accelerate charged particles like electrons and protons to near the speed of light. Some of these may reach Earth, where they will be detected as cosmic ray particles. X-rays scattered by debris ejected in Eta Carinae’s famous 1840 eruption may produce the broader red emission. Credits: NASA/CXC and NASA/JPL-Caltech

    To bridge the gap between low-energy X-ray monitoring and Fermi observations, Hamaguchi and his colleagues turned to NuSTAR. Launched in 2012, NuSTAR can focus X-rays of much greater energy than any previous telescope. Using both newly taken and archival data, the team examined NuSTAR observations acquired between March 2014 and June 2016, along with lower-energy X-ray observations from the European Space Agency’s XMM-Newton satellite over the same period.

    ESA/XMM Newton

    Eta Carinae’s low-energy, or soft, X-rays come from gas at the interface of the colliding stellar winds, where temperatures exceed 70 million degrees Fahrenheit (40 million degrees Celsius). But NuSTAR detects a source emitting X-rays above 30,000 eV, some three times higher than can be explained by shock waves in the colliding winds. For comparison, the energy of visible light ranges from about 2 to 3 eV.

    The team’s analysis, presented in a paper published on Monday, July 2, in Nature Astronomy, shows that these “hard” X-rays vary with the binary orbital period and show a similar pattern of energy output as the gamma rays observed by Fermi.

    The researchers say that the best explanation for both the hard X-ray and the gamma-ray emission is electrons accelerated in violent shock waves along the boundary of the colliding stellar winds. The X-rays detected by NuSTAR and the gamma rays detected by Fermi arise from starlight given a huge energy boost by interactions with these electrons.

    Some of the superfast electrons, as well as other accelerated particles, must escape the system and perhaps some eventually wander to Earth, where they may be detected as cosmic rays.

    “We’ve known for some time that the region around Eta Carinae is the source of energetic emission in high-energy X-rays and gamma rays”, said Fiona Harrison, the principal investigator of NuSTAR and a professor of astronomy at Caltech in Pasadena, California. “But until NuSTAR was able to pinpoint the radiation, show it comes from the binary and study its properties in detail, the origin was mysterious.”

    NuSTAR is a Small Explorer mission led by Caltech and managed by JPL for NASA’s Science Mission Directorate in Washington. NuSTAR was developed in partnership with the Danish Technical University and the Italian Space Agency (ASI). The spacecraft was built by Orbital Sciences Corp., Dulles, Virginia. NuSTAR’s mission operations center is at UC Berkeley, and the official data archive is at NASA’s High Energy Astrophysics Science Archive Research Center. ASI provides the mission’s ground station and a mirror archive. Caltech manages JPL for NASA.

    For more information on NuSTAR, visit:

    https://www.nasa.gov/nustar

    http://www.nustar.caltech.edu

    See the full article here.


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

    Please help promote STEM in your local schools.

    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

     
  • richardmitnick 12:37 pm on May 24, 2018 Permalink | Reply
    Tags: Blazar 3C 279, Gamma-ray emission regions, , NASA Goddard, USA based VLBA   

    From NASA Goddard and NASA/Fermi via phys.org: “Multiple gamma-ray emission regions detected in the blazar 3C 279” 

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    From NASA Goddard Space Flight Center

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    NASA/Fermi Telescope
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    phys.org

    May 23, 2018
    Tomasz Nowakowski

    1
    An example composite image of 3C 279 convolved with a beam size of 0.1 mas (circle in the bottom left corner). The contours represent the total intensity while the color scale is for polarized intensity image of 3C 279. The line segments (length of the segments is proportional to fractional polarization) marks the EVPA direction. Credit: Rani et al., 2018.

    Using very long baseline interferometry (VLBI), astronomers have investigated the magnetic field topology of the blazar 3C 279, uncovering the presence of multiple gamma-ray emission regions in this source. The discovery was presented May 11 in a paper published in The Astrophysical Journal.

    Blazars, classified as members of a larger group of active galaxies that host active galactic nuclei (AGN), are the most numerous extragalactic gamma-ray sources. Their characteristic features are relativistic jets pointed almost exactly toward the Earth. In general, blazars are perceived by astronomers as high-energy engines serving as natural laboratories to study particle acceleration, relativistic plasma processes, magnetic field dynamics and black hole physics.

    NASA’s Fermi Gamma-ray Space Telescope is an essential instrument for blazar studies. The spacecraft is equipped with in the Large Area Telescope (LAT), which allows it to detect photons with energy from about 20 million to about 300 billion electronvolts. So far, Fermi has discovered more than 1,600 blazars.

    NASA/Fermi LAT

    A team of astronomers led by Bindu Rani of NASA’s Goddard Space Flight Center has analyzed the data provided by LAT and by the U.S.-based Very Long Baseline Array (VLBA) to investigate the blazar 3C 279.

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    The studied object, located in the constellation Virgo. It is one of the brightest and most variable sources in the gamma-ray sky monitored by Fermi. The data allowed Rani’s team to uncover more insight into the nature of gamma-ray emission from this blazar.

    “Using high-frequency radio interferometry (VLBI) polarization imaging, we could probe the magnetic field topology of the compact high-energy emission regions in blazars. A case study for the blazar 3C 279 reveals the presence of multiple gamma-ray emission regions,” the researchers wrote in the paper.

    Six gamma-ray flares were observed in 3C 279 between November 2013 and August 2014. The researchers also investigated the morphological changes in the blazar’s jet.

    The team found that ejection of a new component (designated NC2) during the first three gamma-ray flares suggests the VLBI core as the possible site of the high-energy emission. Furthermore, a delay between the last three flares and the ejection of a new component (NC3) indicates that high-energy emission in this case is located upstream of the 43 GHz core (closer to the blazar’s black hole).

    The astronomers concluded that their results are indicative of multiple sites of high-energy dissipation in 3C 279. Moreover, according to the authors of the paper, their study proves that VLBI is the most promising technique to probe the high-energy dissipation regions. However, they added that still more observations are needed to fully understand these features and mechanisms behind them.

    “The Fermi mission will continue observing the GeV sky at least for next couple of years. The TeV missions are on their way to probe the most energetic part of the electromagnetic spectrum. High-energy polarization observations (AMEGO, IXPE, etc.) will be of extreme importance in understanding the high-energy dissipation mechanisms,” the researchers concluded.

    See the full article here.


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    The Fermi Gamma-ray Space Telescope , formerly referred to as the Gamma-ray Large Area Space Telescope (GLAST), is a space observatory being used to perform gamma-ray astronomy observations from low Earth orbit. Its main instrument is the Large Area Telescope (LAT), with which astronomers mostly intend to perform an all-sky survey studying astrophysical and cosmological phenomena such as active galactic nuclei, pulsars, other high-energy sources and dark matter. Another instrument aboard Fermi, the Gamma-ray Burst Monitor (GBM; formerly GLAST Burst Monitor), is being used to study gamma-ray bursts. The mission is a joint venture of NASA, the United States Department of Energy, and government agencies in France, Germany, Italy, Japan, and Sweden.

    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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