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  • richardmitnick 8:06 pm on November 26, 2014 Permalink | Reply
    Tags: , , Astrophysics, , ,   

    From ESO: “ESOcast 69: Revolutionary ALMA Image Reveals Planetary Genesis “ 


    European Southern Observatory

    ESOcast 69 presents the result of the latest ALMA observations, which reveal extraordinarily fine detail that has never been seen before in the planet-forming disc around the young star HL Tauri.

    This revolutionary image is the result of the first observations that have used ALMA with its antennas at close to the widest configuration possible. As a result, it is the sharpest picture ever made at submillimetre wavelengths.

    Watch, enjoy, learn.

    See the full article here.

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  • richardmitnick 5:45 pm on November 26, 2014 Permalink | Reply
    Tags: , Astrophysics, , , ESA European Service Module,   

    From ESA: “European Service Module gets real” 

    ESASpaceForEuropeBanner
    European Space Agency

    26 Nov 2014
    Daniel

    On 17 November, ESA signed a contract in Berlin with the Airbus Defence and Space division to develop and build the European Service Module for Orion, NASA’s new crewed spacecraft. It is the first time that Europe will provide system-critical elements for an American space transportation vehicle.

    m
    Credits: NASA

    NASA Orion Spacecraft
    NASA Orion spacecraft

    NASA intends to use this service module for the 2017 unmanned flight of Orion. The vehicle will perform a high-altitude orbital mission around the Moon. This flight will be a precursor for future Orion human space exploration missions beyond low-Earth orbit.

    The official name of Orion is ‘Multi-Purpose Crew Vehicle’, because the spacecraft can be used to conduct different missions. Eventually, NASA will use Orion to send astronauts to Mars.

    The design of the European Service Module (ESM) is based on the Automated Transfer Vehicle (ATV), the European supply craft for the International Space Station. It is a major achievement, as this is the first European development of a human spacecraft operating beyond Earth orbit.

    ESA Automated Transfer Vehicle
    ESA ATV

    “Being selected by NASA to develop critical elements for the Orion project – currently their most important exploration project – is a clear recognition of Europe’s performance in the frame of the ATV programme,” says Nico Dettmann, Head of ESA’s Space Transportation Department.

    “Cooperation with NASA is going well. It is fruitful and is happening with the same good spirit as with the International Space Station partnership,” he adds.

    The ESM is a cylindrical module with a diameter of 4.5 metres and a total length – main engine excluded – of 2.7 metres. It is fitted with four solar array ‘wings’ with a span of 18.8 metres. Its dry mass is 3.5 metric tons and it can carry 8.6 tons of propellant. Besides propulsion and power, ESM carries consumables.

    The Critical Design Review (CDR) is planned for 2015.

    See the full article here.

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    The European Space Agency (ESA), established in 1975, is an intergovernmental organization dedicated to the exploration of space, currently with 19 member states. Headquartered in Paris, ESA has a staff of more than 2,000. ESA’s space flight program includes human spaceflight, mainly through the participation in the International Space Station program, the launch and operations of unmanned exploration missions to other planets and the Moon, Earth observation, science, telecommunication as well as maintaining a major spaceport, the Guiana Space Centre at Kourou, French Guiana, and designing launch vehicles. ESA science missions are based at ESTEC in Noordwijk, Netherlands, Earth Observation missions at ESRIN in Frascati, Italy, ESA Mission Control (ESOC) is in Darmstadt, Germany, the European Astronaut Centre (EAC) that trains astronauts for future missions is situated in Cologne, Germany, and the European Space Astronomy Centre is located in Villanueva de la Cañada, Spain.

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  • richardmitnick 5:29 pm on November 26, 2014 Permalink | Reply
    Tags: , Astrophysics, , , Magnetosphere,   

    From NASA/Goddard: “NASA’s Van Allen Probes Spot an Impenetrable Barrier in Space” 

    NASA Goddard Banner

    November 26, 2014

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

    Two donuts of seething radiation that surround Earth, called the Van Allen radiation belts, have been found to contain a nearly impenetrable barrier that prevents the fastest, most energetic electrons from reaching Earth.

    NASA Van Allen Probes
    A NASA Van Allen probe

    vab
    A cloud of cold, charged gas around Earth, called the plasmasphere and seen here in purple, interacts with the particles in Earth’s radiation belts — shown in grey— to create an impenetrable barrier that blocks the fastest electrons from moving in closer to our planet.
    Image Credit: NASA/Goddard

    The Van Allen belts are a collection of charged particles, gathered in place by Earth’s magnetic field. They can wax and wane in response to incoming energy from the sun, sometimes swelling up enough to expose satellites in low-Earth orbit to damaging radiation. The discovery of the drain that acts as a barrier within the belts was made using NASA’s Van Allen Probes, launched in August 2012 to study the region. A paper on these results appeared in the Nov. 27, 2014, issue of Nature magazine.

    “This barrier for the ultra-fast electrons is a remarkable feature of the belts,” said Dan Baker, a space scientist at the University of Colorado in Boulder and first author of the paper. “We’re able to study it for the first time, because we never had such accurate measurements of these high-energy electrons before.”

    Understanding what gives the radiation belts their shape and what can affect the way they swell or shrink helps scientists predict the onset of those changes. Such predictions can help scientists protect satellites in the area from the radiation.

    The Van Allen belts were the first discovery of the space age, measured with the launch of a US satellite, Explorer 1, in 1958. In the decades since, scientists have learned that the size of the two belts can change – or merge, or even separate into three belts occasionally. But generally the inner belt stretches from 400 to 6,000 miles above Earth’s surface and the outer belt stretches from 8,400 to 36,000 miles above Earth’s surface.

    NASA Explorer 1
    NASA/Explorer 1

    A slot of fairly empty space typically separates the belts. But, what keeps them separate? Why is there a region in between the belts with no electrons?

    Enter the newly discovered barrier. The Van Allen Probes data show that the inner edge of the outer belt is, in fact, highly pronounced. For the fastest, highest-energy electrons, this edge is a sharp boundary that, under normal circumstances, the electrons simply cannot penetrate.

    “When you look at really energetic electrons, they can only come to within a certain distance from Earth,” said Shri Kanekal, the deputy mission scientist for the Van Allen Probes at NASA’s Goddard Space Flight Center in Greenbelt, Maryland and a co-author on the Nature paper. “This is completely new. We certainly didn’t expect that.”

    The team looked at possible causes. They determined that human-generated transmissions were not the cause of the barrier. They also looked at physical causes. Could the very shape of the magnetic field surrounding Earth cause the boundary? Scientists studied but eliminated that possibility. What about the presence of other space particles? This appears to be a more likely cause.

    1
    This [animation] shows how particles move through Earth’s radiation belts, the large donuts around Earth. The sphere in the middle shows a cloud of colder material called the plasmasphere. New research shows that the plasmasphere helps keep fast electrons from the radiation belts away from Earth.
    Image Credit: NASA/Goddard/Scientific Visualization Studio

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    Plasmasphere

    The radiation belts are not the only particle structures surrounding Earth. A giant cloud of relatively cool, charged particles called the plasmasphere fills the outermost region of Earth’s atmosphere, beginning at about 600 miles up and extending partially into the outer Van Allen belt. The particles at the outer boundary of the plasmasphere cause particles in the outer radiation belt to scatter, removing them from the belt.

    This scattering effect is fairly weak and might not be enough to keep the electrons at the boundary in place, except for a quirk of geometry: The radiation belt electrons move incredibly quickly, but not toward Earth. Instead, they move in giant loops around Earth. The Van Allen Probes data show that in the direction toward Earth, the most energetic electrons have very little motion at all – just a gentle, slow drift that occurs over the course of months. This is a movement so slow and weak that it can be rebuffed by the scattering caused by the plasmasphere.

    This also helps explain why – under extreme conditions, when an especially strong solar wind or a giant solar eruption such as a coronal mass ejection sends clouds of material into near-Earth space – the electrons from the outer belt can be pushed into the usually-empty slot region between the belts.

    “The scattering due to the plasmapause is strong enough to create a wall at the inner edge of the outer Van Allen Belt,” said Baker. “But a strong solar wind event causes the plasmasphere boundary to move inward.”

    A massive inflow of matter from the sun can erode the outer plasmasphere, moving its boundaries inward and allowing electrons from the radiation belts the room to move further inward too.

    The Johns Hopkins Applied Physics Laboratory in Laurel, Maryland, built and operates the Van Allen Probes for NASA’s Science Mission Directorate. The mission is the second in NASA’s Living With a Star program, managed by Goddard.

    For more information about the Van Allen Probe, visit:

    http://www.nasa.gov/vanallenprobes

    See the full article here.

    This post is dedicated to A.A., whose posts are filled with great NASA data and graphics.

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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 4:19 pm on November 26, 2014 Permalink | Reply
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    From Keck: “‘Eye of Sauron’ Provides New Way of Measuring Distances to Galaxies” 

    Keck Observatory

    Keck Observatory

    Keck Observatory

    November 26, 2014
    No Writer Credit

    A team of scientists, led by Dr. Sebastian Hoenig from the University of Southampton, has accurately measured the distance to the nearby NGC 4151 galaxy, using the W. M. Keck Observatory Interferometer. The team employed a new technique they developed, which allows them to measure precise distances to galaxies tens of millions of light years away. The research was published today in the journal Nature.

    Keck Interferometer
    Interferometry at Keck

    ngc
    NGC 4151
    This composite image shows the central region of the spiral galaxy NGC 4151, dubbed the “Eye of Sauron” by astronomers for its similarity to the eye of the malevolent character in The Lord of the Rings. In the “pupil” of the eye, X-rays (blue) from the Chandra X-ray Observatory are combined with optical data (yellow) showing positively charged hydrogen (“H II”) from observations with the 1-meter Jacobus Kapteyn Telescope on La Palma. The red around the pupil shows neutral hydrogen detected by radio observations with the NSF’s Very Large Array. This neutral hydrogen is part of a structure near the center of NGC 4151 that has been distorted by gravitational interactions with the rest of the galaxy, and includes material falling towards the center of the galaxy. The yellow blobs around the red ellipse are regions where star formation has recently occurred.
    Date 27 March 2008
    Source http://www.chandra.harvard.edu/photo/2011/n4151/
    Author X-ray: NASA/CXC/CfA/J.Wang et al.; Optical: Isaac Newton Group of Telescopes, La Palma/Jacobus Kapteyn Telescope, Radio: NSF/NRAO/VLA

    NASA Chandra Telescope
    NASA Chandra schematic
    NASA/Chandra

    Isaac Newton Jacobus Kapteyn Telescope Telescope
    Isaac Newton Jacobus Kapteyn Telescope interior
    Isaac Newton Jacobus Kapteyn Telescope

    NRAO VLA
    NRAO/VLA

    The new technique is similar to that used by land surveyors on earth, who measure both the physical and angular – or ‘apparent’ – size of a distant object, to calculate its distance from Earth.

    Previous reported distances to NGC 4151, which contains a supermassive black hole, ranged from 4- to 29-megaparsecs, but using this new, more accurate method, the researchers calculated the distance to the supermassive black hole as 19 megaparsecs.

    The galaxy NGC415 is dubbed the Eye of Sauron by astronomers for the similarity to its namesake in the film trilogy The Lord of the Rings. As in the famous saga, a ring plays a crucial role in this new measurement. All big galaxies in the universe host a supermassive black hole in their center and in about 10 percent of all galaxies, these supermassive black holes are growing by swallowing huge amounts of gas and dust from their surrounding environments. In this process, the material heats up and becomes very bright — becoming the most energetic sources of emission in the universe known as active galactic nuclei (AGN).

    This hot dust forms a ring around the supermassive black hole and emits infrared radiation, which the researchers used as the ruler. However, the apparent size of the Eye of Sauron’s ring is so small, the observations were carried out using the Keck Interferometer, which combines Keck Observatory’s twin 10-meter telescopes — already the largest telescopes on Earth — to achieve the resolving power of an 85m telescope.

    To measure the physical size of the dusty ring, the researchers measured the time delay between the emission of light from close to the black hole and the more distant infrared emission. The distance from the center to the hot dust is simply this delay divided by the speed of light.

    By combining the physical size of the dust ring with the apparent size measured with the Keck Interferometer, the researchers were able to determine a distance to NGC 4151.

    “One of the key findings is that the distance determined in this new fashion is quite precise — with 90 percent accuracy,” Hoenig said. “In fact, this method, based on simple geometrical principles, gives the most precise distances for remote galaxies. Moreover, it can be readily used on many more sources than current methods. Such distances are key in pinning down the cosmological parameters that characterize our universe or in accurately measuring black hole masses. Indeed, NGC 4151 is a key to calibrating various techniques of estimating black hole masses. Our new distance implies that these masses may have been systematically underestimated by 40 percent.”

    Hoenig, together with colleagues in Denmark and Japan, is currently setting up a new program to extend their work to many more AGN. The goal is to establish precise distances to a dozen galaxies using this technique and use them to constrain cosmological parameters to within few per cent. Combined with other measurements, this will provide a better understanding of the history of expansion of our universe.

    The Keck Interferometer began construction in 1997, and finished its mission in 2012. It was funded by NASA and managed by JPL. JPL is managed by Caltech for NASA.

    Keck Observatory is a private 501(c) 3 non-profit organization and a scientific partnership of the California Institute of Technology, the University of California and NASA.

    See the full article here.

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

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

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

    Keck NASA

    Keck Caltech

     
  • richardmitnick 9:12 am on November 26, 2014 Permalink | Reply
    Tags: , Astrophysics, , ,   

    From ESO: “A Colourful Gathering of Middle-aged Stars” 


    European Southern Observatory

    26 November 2014
    Richard Hook
    ESO, Public Information Officer
    Garching bei München, Germany
    Tel: +49 89 3200 6655
    Cell: +49 151 1537 3591
    Email: rhook@eso.org

    The MPG/ESO 2.2-metre telescope at ESO’s La Silla Observatory in Chile has captured a richly colourful view of the bright star cluster NGC 3532. Some of the stars still shine with a hot bluish colour, but many of the more massive ones have become red giants and glow with a rich orange hue.

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    ESO 2.2 meter telescope
    ESO 2.2 meter telescope interior
    ESO 2.2 Meter Telescope at LaSilla

    ESO LaSilla Long View
    ESO/LaSilla

    NGC 3532 is a bright open cluster located some 1300 light-years away in the constellation of Carina (The Keel of the ship Argo). It is informally known as the Wishing Well Cluster, as it resembles scattered silver coins which have been dropped into a well. It is also referred to as the Football Cluster, although how appropriate this is depends on which side of the Atlantic you live. It acquired the name because of its oval shape, which citizens of rugby-playing nations might see as resembling a rugby ball.

    This very bright star cluster is easily seen with the naked eye from the southern hemisphere. It was discovered by French astronomer Nicolas Louis de Lacaille whilst observing from South Africa in 1752 and was catalogued three years later in 1755. It is one of the most spectacular open star clusters in the whole sky.

    NGC 3532 covers an area of the sky that is almost twice the size of the full Moon. It was described as a binary-rich cluster by John Herschel who observed “several elegant double stars” here during his stay in southern Africa in the 1830s. Of additional, much more recent, historical relevance, NGC 3532 was the first target to be observed by the NASA/ESA Hubble Space Telescope, on 20 May 1990.

    NASA Hubble Telescope
    NASA Hubble schematic
    NASA/ESA Hubble

    This grouping of stars is about 300 million years old. This makes it middle-aged by open star cluster standards [1]. The cluster stars that started off with moderate masses are still shining brightly with blue-white colours, but the more massive ones have already exhausted their supplies of hydrogen fuel and have become red giant stars. As a result the cluster appears rich in both blue and orange stars. The most massive stars in the original cluster will have already run through their brief but brilliant lives and exploded as supernovae long ago. There are also numerous less conspicuous fainter stars of lower mass that have longer lives and shine with yellow or red hues. NGC 3532 consists of around 400 stars in total.

    The background sky here in a rich part of the Milky Way is very crowded with stars. Some glowing red gas is also apparent, as well as subtle lanes of dust that block the view of more distant stars. These are probably not connected to the cluster itself, which is old enough to have cleared away any material in its surroundings long ago.

    This image of NGC 3532 was captured by the Wide Field Imager instrument at ESO’s La Silla Observatory in February 2013.

    ESO Wide Field Imager 2.2m LaSilla
    WFI at LaSilla

    Notes

    [1] Stars with masses many times greater than the Sun have lives of just a few million years, the Sun is expected to live for about ten billion years and low-mass stars have expected lives of hundreds of billions of years — much greater than the current age of the Universe.

    See the full article here.

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  • richardmitnick 6:45 pm on November 25, 2014 Permalink | Reply
    Tags: , Astrophysics, , ,   

    From NASA/Blue Shift: “Novae in Different Lights” 

    NASA Blueshift
    NASA Blueshift

    First Article:

    A “Noval” Mystery

    November 10, 2014
    Maggie Masetti

    The mystery around Nova V959 Mon was recently deciphered with the use of multiwavelength light – including radio, X-ray, and gamma-ray.

    First off, what is a nova? It’s basically a huge thermonuclear explosion that’s caused when a dense white dwarf star pulls material from an orbiting companion star onto itself. The resulting blast spews gaseous debris outward.

    And what’s the mystery around V959 Mon? Well, in 2012, astronomers using the Fermi Gamma-ray Space Telescope noticed that V959 Mon gave off gamma-rays, which was a new and surprising development in the study of novae. Also now astronomers had to figure out the mechanism by which this occurred.

    f
    Credit: NASA/Sonoma State

    Fortunately, there were radio observations made at the same time with the Karl G. Jansky Very Large Array (VLA), as well as later ones by the Very Long Baseline Array (VLBA) and the European VLBI network. The VLA data indicated that there were subatomic particles moving nearly at the speed of light, that were interacting with the magnetic field in the shock front. Both radio and gamma-ray emission requires such fast-moving particles – so by locating the site of one, we can locate the other. The later VLBI observations show two “distinct knots of radio emission,” which were moving away from each other.

    Adding all these together with more VLA observations in 2014 and UK observations made with e-MERLIN, finally provided scientists with the needed information for piecing this together.

    NRAO VLA
    Credit: Dave Finley, courtesy National Radio Astronomy Observatory and Associated Universities, Inc.

    NRAO VLBA
    NRAO VLBA

    European VLBI
    European VLBI

    eMerlin Radio Telecope Array
    e-MERLIN

    What is happening is this. The white dwarf star, which is the nuclear ash of a star like the sun, pulls matter – fresh fuel – from its companion star to itself. When enough fuel accumulates after thousands of years, the surface layer detonates in a thermonuclear explosion. This seems to throw off the envelope preferentially in the orbital plane of the binary. Later, the white dwarf blows off a wind of particles, and this wind moves even faster than the material the star initially threw off. When this faster flow of particles hits the slower moving material, it creates a shock, which accelerates the particles to the speeds necessary to produce gamma-rays and the knots of radio emission.

    Says Laura Chomiuk, Michigan State University researcher, “We not only found where the gamma-rays came from, but also got a look at a previously-unseen scenario that may be common in other nova explosions.”

    And indeed, since the 2012 outburst of V959 Mon, the Fermi telescope has detected gamma-rays from three additional nova explosions.

    k
    These images show Fermi data centered on each of the four gamma-ray novae observed by the LAT. Colors indicate the number of detected gamma rays with energies greater than 100 million electron volts (blue indicates lowest, yellow highest).
    Image Credit: NASA/DOE/Fermi LAT Collaboration

    We got the chance to interview Laura Chomiuk to ask her more about her research on this nova and about the scientific questions that surrounded it.

    NASA Blueshift: Tell us a little bit about yourself! How did you get into working on novae?

    Laura Chomiuk: I’ve just started my second year as a professor at Michigan State. I’m loving my job so far – working with a lot of excited and exciting students and postdocs, having the freedom to think about interesting scientific questions, and be able to take advantage of our lovely national observatories. I actually got into studying novae because of one of these lovely public observatories – the Very Large Array. After graduate school, I spent some time hanging out at the telescope, helping polish up some of its new capabilities, and a team of scientists came knocking because they wanted help observing novae with the VLA. I got so lucky that day! It had never occurred to me to study novae before, but they turned out to be so much richer and more interesting and well, weirder, than I could have dreamed!

    NASA Blueshift: Could you explain your research in a nutshell?

    Laura Chomiuk: Novae are supposed to be these relatively low-energy, garden variety explosions that we understand really well, but they keep throwing surprises at us. The most recent surprise was that they appear to emit really high energy light with gamma-ray wavelengths, as detected by NASA’s Fermi Gamma-Ray Telescope. Gamma-ray sources are rare in our galaxy, and nobody expected gamma-rays from novae, because gamma-rays are typically produced in really fast, violent shocks, and novae weren’t supposed to have such energetic blasts. Our team was able to zoom in one of these gamma-ray producing novae and take really detailed images using a bunch of radio telescopes. These pictures showed the expansion of the nova explosion and also showed how the nova could produce gamma-rays. We found that the nova explosion isn’t at all spherical like a ball, but instead it is elongated like an hourglass. The fast moving material in the hourglass plows into really dense, slow-moving stuff that hangs out at the waist of the hourglass, and this interaction gives you the violent shocks needed for gamma-ray production.

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    A nova does not explode like an expanding ball, but instead throws out gas in different directions at different times and different speeds. When this gas inevitably crashes together, it produces shocks and high-energy gamma-ray photons. The complex explosion and gas collisions in nova V959 Mon is illustrated above. In the first days of the nova explosion, dense relatively slow-moving material is expelled along the binary star system’s equator (yellow material in bottom left panel). Over the next several weeks, fast winds pick up and are blown off the binary, but they are funneled along the binary star system’s poles (blue material in bottom central panel). The equatorial and polar material crashes together at their intersection, producing shocks and gamma-ray emission (red regions in central panel). Finally, at later times, the nova stops blowing a wind, and the material drifts off into space, the fireworks finished (in bottom right panel). Our [artist conception] images, in the top row, illustrate these phases. In the top left panel, the color image shows the bulk of the nova ejecta, as imaged by e-MERLIN. Around that time, the shocks were imaged with the EVN array, and showed the locations of shocks and gamma-ray production (shown here as black contours, tracing synchrotron emission). The center panel shows similar components one month later, when the shocked knots have expanded and a third component has become visible. At late times (color image in the top right panel), the brightest, densest material is now oriented differently, corresponding to the slower moving equatorial material.
    Credit: L. Chomiuk, B. Saxton, NRAO/AUI/NSF

    NASA Blueshift: What are novae? What do scientists hope to learn about them?

    Laura Chomiuk: Novae are the most common nuclear explosions in the Universe. They happen when a white dwarf star (which is a compact core left over when a star like our Sun dies) has a nearby companion star, and the white dwarf manages to pull gas off its companion star. The gas on the white dwarf collects and grows in pressure over time, until nuclear fusion explosively turns on. Then all that collected gas gets blown off into space at speeds of thousands of miles per second—that is the nova! After the nova, the whole process can actually repeat. The white dwarf will start to pull gas from its companion star again, and will likely host another nova sometime in the future—it could be 10 years, or a million years.

    I’m really interested in novae because there is still so much we don’t understand about them. They are supposed to be relatively simple, common explosions, but they show all this surprising behavior—the strange hourglass geometry and strong shocks in our recent paper are just one example. For example, a nova is supposed to be a single nuclear explosion, but novae often look like they have multiple outbursts in rapid succession, and continue to expel material for sometimes months after the initial explosion. Ultimately, I would like to understand how much mass and energy are released by nova explosions, and the physics that determines this release. But first we have to wade through a lot of strange and complicated behaviors!

    NASA Blueshift: What is V959 Mon? What does its name mean? What made it the right candidate for these observations, compared to other systems?

    Laura Chomiuk: V959 Mon was the subject of our paper. It was one of the first novae detected in gamma-rays, and turns out to be a really nice, nearby novae to study. The fact that it is unusually nearby [6500 light years away] was convenient, because it meant the nova was brighter than usual, and allowed for higher-quality images. I wish every nova would be as well-behaved as V959 Mon.

    The name V959 Mon is typical of how we name variable stars. The ‘V’ stands for variable, meaning that its brightness changes with time. It was the 959th variable star discovered in the constellation Monoceros (a Monoceros is apparently a unicorn, not a rhinoceros as I had been believing until I just googled it).

    NASA Blueshift: How do different wavelengths of light help you understand nova explosions? In particular, how do radio observations help you understand gamma-ray emissions when they’re at opposite ends of the electromagnetic spectrum?

    Laura Chomiuk: Each wavelength regime gives unique insights into the complex explosions of novae, and in the case of radio and gamma-ray wavelengths, these insights are very complimentary. Violent shocks in astronomical explosions can accelerate particles to near the speed of light, creating so called ‘cosmic rays’. It is the interaction of these cosmic rays with their surroundings that produces gamma-rays and radio emission. So in the case of V959 Mon, radio waves acted as a tracer of gamma-ray production.

    NASA Blueshift: How does your collaboration work? How do you coordinate with researchers working in multiple wavelengths, especially with systems that are event-based and rapidly changing?

    Laura Chomiuk: Our collaboration involves people from all over the world, and I really am proud of the number of scientists and telescopes that worked together to collect observations for V959 Mon. When it became clear that V959 Mon was an unusually interesting, nearby event, we sent out a telegram to all astronomers letting them know that we planned to observe it with one particular radio telescope, the VLA. This inspired astronomers from other parts of the U.S. and Europe to try and obtain additional data on their telescopes, and we were in regular contact about how best to cover this interesting event. To make sure that we get good coverage on a time-variable event, it’s very important to stay focused and keep the channels of communication open. We have regular telecons and email discussions, and try to meet face-to-face whenever we can!

    NASA Blueshift: What makes this discovery new/interesting/useful for scientists in better understanding novae, gamma-rays, etc.? What question(s) did this help answer?

    Laura Chomiuk: Astronomical sources that produce gamma-rays really are unusual and exceptionally energetic. In our Galaxy, there are only a few classes of stellar objects that produce gamma-rays: neutron star pulsars, accreting compact objects—and now novae. Novae show that a much wider range of physical conditions can result in these most energetic of photons than previously thought.

    Also, our study sheds some light on how nova explosions are actually powered. Our imaging of V959 Mon is consistent with a scenario wherein the binary star system whips around inside the gaseous nova envelope, and actually transfers some of the binary orbit’s energy to the nova ejecta. This “binary eggbeater” process gives an extra kick to the explosion and shapes the nova ejecta, potentially explaining some of the complexities we see in novae.

    NASA Blueshift: And, of course, what new questions did it create? What’s next?

    Laura Chomiuk: Since V959 Mon, Fermi has gone on to detect gamma-rays from several more novae, implying that perhaps all novae produce these most energetic photons. However, it remains unclear if the process for producing gamma-rays we identified in V959 Mon applies to these other novae. We are continuing to observe novae at radio, optical, X-ray, and gamma-ray wavelengths to understand their complex explosions, strong shocks, and ejecta geometries.

    Second Article:

    In part one of this series, we talked to researcher Laura Chomiuk about the scientific mysteries of novae V959 Mon. She has collaborated with two Blueshifters, Koji Mukai, and Tommy Nelson, who also study novae, but primarily at X-ray energies. We chatted with Tommy to learn more about his research in general and in specific regard to V959 Mon.

    p;
    These images show Fermi data centered on each of the four gamma-ray novae observed by the LAT. Colors indicate the number of detected gamma rays with energies greater than 100 million electron volts (blue indicates lowest, yellow highest).
    Image Credit:NASA/DOE/Fermi LAT Collaboration

    NASA Blueshift: Can you tell our readers a little about yourself?

    Tommy Nelson: My name is Tommy Nelson, and I’m a research associate and lecturer at the University of Minnesota in Minneapolis. My background is in X-ray astronomy, primarily studies of novae in outburst and other accreting white dwarf binary systems. I was a postdoctoral researcher at Goddard for almost 3 years after graduate school, where I worked with Koji Mukai on science, and the wonderful Blueshift team on a few outreach projects. I left NASA primarily for family reasons – my spouse got a job here in Minnesota. However, I continued to work with Koji, Laura Chomiuk, and our colleague Jeno Sokoloski at Columbia University after I moved – mainly because they are all wonderful collaborators and I have so much fun working with them. Analyzing radio observations of novae was definitely a new, challenging experience for me, but it has given me a new, refreshing view of nova outbursts that I would not have obtained from X-ray studies alone.

    m
    The white dwarf star in V407 Cygni, shown here in an artist’s concept, went nova in 2010. Scientists think the outburst primarily emitted gamma rays (magenta) as the blast wave plowed through the gas-rich environment near the system’s red giant star. Image Credit: NASA’s Goddard Space Flight Center/S. Wiessinger

    NASA Blueshift: Laura told us quite a bit about novae and her observations of them. How do x-ray observations add to the understanding of novae?

    Tommy Nelson: X-ray observations of novae are wonderful because they can reveal the presence of any shocks in the ejected material. This is important if you want to understand why novae make gamma-rays, because our current theories of particle acceleration identify shocks as the location where particles are sped up to very high velocities. The detection of X-rays at energies above 1 keV indicates hot gas with temperatures greater than 1 million degrees – an undeniable signature of shocks. By measuring the temperature of the X-ray emitting gas, we can also figure out the difference in velocities between the fast and slow material, another important factor in determining how well shocks can accelerate particles.

    X-ray observations are the ideal compliment to radio studies. While the VLA can reveal the shape of the ejecta and the amount of matter being thrown off during the outburst, X-rays add new information by telling us about the dynamics and energetics of the nova explosion.

    k
    Credit: Tommy Nelson

    NASA Blueshift: You also worked on the multiwavelength studies of the nova V959 Mon, which we interviewed Laura Chomiuk about. Your team’s first paper, led by Laura, focused on radio and gamma-ray observations. What other wavelengths did you use, and what additional information have those observations given you about this source?

    Tommy Nelson: In addition to the radio observations that Laura’s paper focuses on, we also obtained X-ray observations of V959 Mon during the outburst with Swift, Chandra, and Suzaku. The X-rays have allowed us to constrain the difference in velocity between the two phases of mass ejection: something that wasn’t possible with the radio data alone. We also confirmed the internal shock picture by watching the X-rays become less absorbed by gas over a period of 3 months. This drop in absorption is due to the expansion of the slower ejected material ahead of the shock front. In other words, everything we see in the X-rays and radio ties together nicely! I’m currently writing these results up and we hope the paper will be out in the near future.

    NASA SWIFT Telescope
    NASA/Swift

    NASA Chandra TelescopeNASA Chandra schematic
    NASA/Chandra

    Suzaku ISAS telescope
    Suzaku

    NASA Blueshift: What’s next for your research regarding novae?

    Tommy Nelson: For now, my research will continue to focus on getting well-sampled, multiwavelength data sets for novae in outburst. We have really only started obtaining coordinated radio, optical and X-ray observations for novae in the last few years, and so the number of well studied systems is still small. We know that the behavior of novae varies widely from object to object, so in order to pin down some of the fundamental physical processes taking place—particularly those related to mass ejection—we need to increase our sample size.

    NASA Blueshift: Thanks, Tommy!

    We also chatted briefly with Koji to learn a little more about his involvement with the research. We love how it illustrates what a small community astronomy can be.

    Koji Mukai: My involvement with this group initially started in February, 2006, with a phone call from Dr. Jennifer (Jeno) Sokoloski (who is now at Columbia University), because a star called RS Oph went nova, and Jeno wanted to organize an campaign of X-ray observations very quickly. We had met at conferences before, and Jeno knew I knew people who worked on RXTE and Swift at Goddard. I suggested using RXTE, and we ended up getting some really nice early X-ray data on RS Oph. Jeno and I have been collaborating ever since.

    NASA RXTE
    NASA/RXTE The Rossi X-ray Timing Explorer

    This 2006 explosion of RS Oph was observed by so many people using so many different instruments that a conference on this one nova was organized. There I met Tommy Nelson, who was working on a different set of X-ray data on RS Oph as a graduate student at Wisconsin. I ended up hiring Tommy as my post-doc to work here at Goddard. One day, Tommy was chatting with some friends (probably over coffee), who happened to mention that there is this new gamma-ray source which appears to be a nova. That’s how we first found out about gamma-rays from novae. Later, Tommy and I started working with Jeno and others on radio observation of novae, and it turns out Laura Chomiuk and Tommy are close friends from their Wisconsin days. Small world.

    See the first article here, the second article here.

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    Blueshift is produced by a team of contributors in the Astrophysics Science Division at Goddard. Started in 2007, Blueshift came from our desire to make the fascinating stuff going on here every day accessible to the outside world.

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  • richardmitnick 4:26 pm on November 25, 2014 Permalink | Reply
    Tags: , Astrophysics, , , ,   

    From Starts With a Bang: “Dark Matter and the Origin of Life” 

    Starts with a bang
    Starts with a Bang

    November 25, 2014

    jb
    James Bullock, UC Irvine

    How material we’d never notice if we kept our eyes on Earth alone helped give rise to all that we are.

    The origin of life is one of the great mysteries of science. Even the definition of life is widely debated. But one thing that’s agreed upon is this: complex molecules are required. This is because life does amazingly elaborate things: it extracts energy from its environment, it replicates, and it evolves by natural selection. Intricate biochemical machinery like this requires a set of intricate building blocks.

    Nothing of the kind emerged from the Big Bang. It was just too hot, too dense, and expanding too fast for anything complicated to form. So what allowed the Universe to go from this simple beginning to something as inticate as life? Well, initially at least, it was dark matter. If you took our Universe, kept the overall geometry and initial conditions the same, and just removed the dark matter, it’s hard to understand how anything as complex as life could have developed. As mysterious and removed as it seems, dark matter, according to standard cosmology, has been absolutely essential for life.

    Let’s start with the Big Bang. It served up a pretty bland primordial soup as far as the matter we’re used to is concerned: a smooth ionized gas consisting of hydrogen and helium. No big atoms, certainly no molecules or planets. If our story ended here then we’d have the most boring universe imaginable. Hydrogen and helium don’t allow much in the way of complexity. You can’t build a self-replicating cell out of hydrogen and helium, much less a dinosaur or an upright ape. But flash forward 13.8 billion years and we’ve got complex structure everywhere, a Galaxy filled with planets, and at least one place where life has blossomed on the back of carbon-based chemistry.

    6
    The 6 most important elements for life on Earth. Only one (H) was given to us in the Big Bang.(No image credit)

    None of this would have happened if the Big Bang had emerged with only hydrogen and helium. Thankfully our Universe was also born with an additional kind of matter, one that does not appear on the periodic table: dark matter. The dark matter is important because of its gravity. While it doesn’t reflect light or interact strongly with normal matter, it does have mass. Importantly, there is about five times as much dark matter as normal matter. Without the extra gravitational tug from dark matter we would not exist.

    While stars are ultimately responsible for forging elements heavier than hydrogen and helium, dark matter has been the prime factor allowing stars to form in the first place. On top of this, the dark matter that surrounds galaxies today is also essential for recapturing elements that get blown out by supernovae into intergalactic space. Dark matter allows these elements to get recycled back into galaxies, where they can be put to good use making new stars, planets, and (in a few cases) astronomers. Let’s dig a little deeper to see how this actually works.

    bc
    All sky view of our home galaxy, the Milky Way. Brought to you by dark matter. http://apod.nasa.gov/apod/image/1105/3000_CC_BY-NC.jpg
    In a big picture sense, modern cosmology tells us that our Universe is governed by two mysterious substances — dark matter and dark energy — locked in an epic battle to shape the character of our cosmos.

    c
    The Ancient and Medieval cosmos as depicted in Peter Apian’s Cosmographia (Antwerp, 1539).

    Schema huius præmiʃʃæ diuiʃionis Sphærarum.
    COELVM EMPIREVM HABITACVLVM DEI ET OMNIVM ELECTORVM
    The scheme of the aforementioned division of spheres. · The empyrean (fiery) heaven, dwelling of God and of all the selected · 10 Tenth heaven, first cause · 9 Ninth heaven, crystalline · 8 Eighth heaven of the firmament · 7 Heaven of Saturn · 6 Jupiter · 5 Mars · 4 Sun · 3 Venus · 2 Mercury · 1 Moon
    28 December 2005
    from Edward Grant, “Celestial Orbs in the Latin Middle Ages”, Isis, Vol. 78, No. 2. (Jun., 1987), pp. 152-173.

    Dark matter plays the role of Creator: its gravity is pulling sections of the Universe to buckle back on itself, forming galaxies along the way. Dark energy is doing just the opposite. It’s fighting the collapse by propelling the universe to expand at an ever faster rate. Luckily for us, dark matter has been winning for most of cosmic time, particularly in the all-important early stages. Our Galaxy, the Milky Way, would have never collapsed out of the expanding rush of the Big Bang without the aid of dark matter’s pull. That means no Sun, no Earth, and no you.

    About 14 billion years ago, when that soup of hydrogen, helium, and dark matter emerged from the Big Bang, everything was expanding. This isn’t the best situation for building complexity. No prokaryote is going to spontaneously emerge in a Universe consisting of hydrogen atoms flying away from each other in an expanding horde.

    d
    A cosmological simulation of dark matter growing clumpier over time. Image credit: Andrey Kravtsov

    But not every part of the Universe kept expanding. Though born smoother than the calmest sea, our Universe was not perfectly flawless from the beginning. There were tiny irregularities — 0.001% in density — that began to grow over time because of gravity. Areas with more matter attracted even more over time. The dark matter played a key role: it provided extra mass and made structure grow much faster than it would have otherwise. The dark matter also remained much clumpier in the beginning than the normal matter for another reason: it doesn’t interact with light. Early on, the blindingly bright ambient photons left over from the big bang scattered off of protons, smoothing out the distribution. This process (called Silk Damping) took an already smooth distribution of normal matter and made it even smoother. Light can’t scatter off of dark matter, so the dark matter remained relatively clumpy on the length scales that would eventually grow into galaxies.

    Cosmic Microwave Background  Planck
    Cosmic Microwave Background per ESA/Planck

    Had there been no dark matter in the beginning, there would have been a much lower level of primordial structure and much less gravity to make those tiny imperfections grow. The resulting universe today would be unrecognizable. Virtually nothing akin to the galaxies we know would exist and dark energy would have won out long ago to prevent new structure formation. Instead, as time went on, gravity dragged more and more dark matter into the places that started off mildly over-dense. Eventually, those pockets of extra mass broke away from the general expansion, funneling gas and dark matter to collapse back in on itself. Galaxies began to form within those pockets of dark matter while the space in between galaxies kept right on expanding.

    s
    The original primordial soup was pretty bland. Modified from an image taken from http://www.mbio.ncsu.edu/jwb/soup.html

    These pockets of collapsed dark matter — dark matter halos — govern where galaxies form. Stars in galaxies convert hydrogen and helium into ever heavier elements, including the carbon, nitrogen, and oxygen that are essential for life on Earth. But when massive stars explode as supernovae they expel key elements for life back out into space. They are launched with immense speeds, hundreds of kilometers per second, and have so much energy that they would be blown out of their host galaxies forever without the huge gravitational cocoon of their dark matter halos to trap them.

    h
    Dark matter halos provide gravitational cocoons around galaxies. They capture heavy elements blown out of supernovae allowing them to fall back in, building ever richer reservoirs of the heavy elements essential for life. Credit: STScI

    Dark matter around galaxies allows much of the ejecta from supernovae to recycle back into the next generation of stars and planets rather than escape into intergalactic space. Galaxies become steadily enriched with heavy elements over time and develop a sort of galactic ecosystem that contains heavy atoms and even complex organic molecules. Our home planet — with its rocky surface and liquid water — would likely never have taken shape without the Milky Way’s dark matter halo to trap escaping material.

    Over the last 14 billion years or so, dark matter has been driving the Universe to ever increasing levels of complexity. Early on, it easily won its battle with dark energy in this regard. But if indications are correct, all of this is about to change. Relative to dark matter, the effect of dark energy is growing stronger with time. Dark matter is doomed to lose its cosmic arm wrestling match in a big way. When the Universe is a few times its current age, virtually all new galaxy formation will cease.

    Because of dark energy’s inevitable triumph, our Universe is approaching a pinnacle in complexity. At some point in the future, fresh fuel for star formation will stop falling into galaxies and no new stars will be able to form. This will represent a high-point for the likelihood of life in our Universe as well. Just before the rate of star formation drops away to a negligible rate, the Universe will be flush with heavy atoms and complex molecules. It will be a last triumphant opportunity for our Universe to produce life, and maybe even a few critters to look up at the stars and wonder how they came to be.

    See the full article here.

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

     
  • richardmitnick 11:24 am on November 25, 2014 Permalink | Reply
    Tags: , , Astrophysics, , , Gamma Ray Bursts,   

    From AAAS: “Complex life may be possible in only 10% of all galaxies” 

    AAAS

    AAAS

    24 November 2014
    Adrian Cho

    The universe may be a lonelier place than previously thought. Of the estimated 100 billion galaxies in the observable universe, only one in 10 can support complex life like that on Earth, a pair of astrophysicists argues. Everywhere else, stellar explosions known as gamma ray bursts would regularly wipe out any life forms more elaborate than microbes. The detonations also kept the universe lifeless for billions of years after the big bang, the researchers say.

    “It’s kind of surprising that we can have life only in 10% of galaxies and only after 5 billion years,” says Brian Thomas, a physicist at Washburn University in Topeka who was not involved in the work. But “my overall impression is that they are probably right” within the uncertainties in a key parameter in the analysis.

    Scientists have long mused over whether a gamma ray burst could harm Earth. The bursts were discovered in 1967 by satellites designed to spot nuclear weapons tests and now turn up at a rate of about one a day. They come in two types. Short gamma ray bursts last less than a second or two; they most likely occur when two neutron stars or black holes spiral into each other. Long gamma ray bursts last for tens of seconds and occur when massive stars burn out, collapse, and explode. They are rarer than the short ones but release roughly 100 times as much energy. A long burst can outshine the rest of the universe in gamma rays, which are highly energetic photons.

    That seconds-long flash of radiation itself wouldn’t blast away life on a nearby planet. Rather, if the explosion were close enough, the gamma rays would set off a chain of chemical reactions that would destroy the ozone layer in a planet’s atmosphere. With that protective gas gone, deadly ultraviolet radiation from a planet’s sun would rain down for months or years—long enough to cause a mass die-off.

    How likely is that to happen? Tsvi Piran, a theoretical astrophysicist at the Hebrew University of Jerusalem, and Raul Jimenez, a theoretical astrophysicist at the University of Barcelona in Spain, explore that apocalyptic scenario in a paper in press at Physical Review Letters.

    Astrophysicists once thought gamma ray bursts would be most common in regions of galaxies where stars are forming rapidly from gas clouds. But recent data show that the picture is more complex: Long bursts occur mainly in star-forming regions with relatively low levels of elements heavier than hydrogen and helium—low in “metallicity,” in astronomers’ jargon.

    Using the average metallicity and the rough distribution of stars in our Milky Way galaxy, Piran and Jimenez estimate the rates for long and short bursts across the galaxy. They find that the more-energetic long bursts are the real killers and that the chance Earth has been exposed to a lethal blast in the past billion years is about 50%. Some astrophysicists have suggested a gamma ray burst may have caused the Ordovician extinction, a global cataclysm about 450 million years ago that wiped out 80% of Earth’s species, Piran notes.

    The researchers then estimate how badly a planet would get fried in different parts of the galaxy. The sheer density of stars in the middle of the galaxy ensures that planets within about 6500 light-years of the galactic center have a greater than 95% chance of having suffered a lethal gamma ray blast in the last billion years, they find. Generally, they conclude, life is possible only in the outer regions of large galaxies. (Our own solar system is about 27,000 light-years from the center.)

    Things are even bleaker in other galaxies, the researchers report. Compared with the Milky Way, most galaxies are small and low in metallicity. As a result, 90% of them should have too many long gamma ray bursts to sustain life, they argue. What’s more, for about 5 billion years after the big bang, all galaxies were like that, so long gamma ray bursts would have made life impossible anywhere.

    But are 90% of the galaxies barren? That may be going too far, Thomas says. The radiation exposures Piran and Jimenez talk about would do great damage, but they likely wouldn’t snuff out every microbe, he contends. “Completely wiping out life?” he says. “Maybe not.” But Piran says the real issue is the existence of life with the potential for intelligence. “It’s almost certain that bacteria and lower forms of life could survive such an event,” he acknowledges. “But [for more complex life] it would be like hitting a reset button. You’d have to start over from scratch.”

    The analysis could have practical implications for the search for life on other planets, Piran says. For decades, scientists with the SETI Institute in Mountain View, California, have used radio telescopes to search for signals from intelligent life on planets around distant stars. But SETI researchers are looking mostly toward the center of the Milky Way, where the stars are more abundant, Piran says. That’s precisely where gamma ray bursts may make intelligent life impossible, he says: “We are saying maybe you should look in the exact opposite direction.”

    Allen Telescope Array
    Allen Telescope Array, part of SETI Institute

    Arecibo
    Arecibo Radio Telescope used by SETI@home

    NRAO GBT
    NRAO Green Bank Radio Telescope

    Jodrell Bank Lovell Telescope
    Jodrell Bank Lovell Radio Telescope

    See the full article here.

    The American Association for the Advancement of Science is an international non-profit organization dedicated to advancing science for the benefit of all people.

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  • richardmitnick 11:00 am on November 25, 2014 Permalink | Reply
    Tags: , Astrophysics, , ,   

    From NASA: “Young Volcanoes on the Moon” 

    NASA

    NASA

    Nov 24, 2014
    Author: Dr. Tony Phillips | Production editor: Dr. Tony Phillips | Credit: Science@NASA

    Nov 24, 2014: Back in 1971, Apollo 15 astronauts orbiting the Moon photographed something very odd. Researchers called it “Ina,” and it looked like the aftermath of a volcanic eruption.

    There’s nothing odd about volcanoes on the Moon, per se. Much of the Moon’s ancient surface is covered with hardened lava. The main features of the “Man in the Moon,” in fact, are old basaltic flows deposited billions of years ago when the Moon was wracked by violent eruptions. The strange thing about Ina was its age.

    Planetary scientists have long thought that lunar volcanism came to an end about a billion years ago, and little has changed since. Yet Ina looked remarkably fresh. For more than 30 years Ina remained a mystery, a “one-off oddity” that no one could explain.

    Turns out, the mystery is bigger than anyone imagined. Using NASA’s Lunar Reconnaissance Orbiter, a team of researchers led by Sarah Braden of Arizona State University has found 70 landscapes similar to Ina. They call them “Irregular Mare Patches” or IMPs for short.


    A new ScienceCast video explores the mystery of recent lunar volcanism. Play it

    “Discovering new features on the lunar surface was thrilling!” says Braden. “We looked at hundreds of high-resolution images, and when I found a new IMP it was always the highlight of my day.”

    “The irregular mare patches look so different than more common lunar features like impact craters, impact melt, and highlands material,” she says. “They really jump out at you.”

    On the Moon, it is possible to estimate the age of a landscape by counting its craters. The Moon is pelted by a slow drizzle of meteoroids that pepper its surface with impact scars. The older a landscape, the more craters it contains.

    Some of the IMPs they found are very lightly cratered, suggesting that they are no more than 100 million years old. A hundred million years may sound like a long time, but in geological terms it’s just a blink of an eye. The volcanic craters LRO found may have been erupting during the Cretaceous period on Earth–the heyday of dinosaurs. Some of the volcanic features may be even younger, 50 million years old, a time when mammals were replacing dinosaurs as dominant lifeforms.

    “This finding is the kind of science that is literally going to make geologists rewrite the textbooks about the Moon,” says John Keller, LRO project scientist at the Goddard Space Flight Center.

    IMPs are too small to be seen from Earth, averaging less than a third of a mile (500 meters) across in their largest dimension. That’s why, other than Ina, they haven’t been found before. Nevertheless, they appear to be widespread around the nearside of the Moon.

    “Not only are the IMPs striking landscapes, but also they tell us something very important about the thermal evolution of the Moon,” says Mark Robinson of Arizona State University, the principal investigator for LRO’s high resolution camera. “The interior of the Moon is perhaps hotter than previously thought.”

    “We know so little of the Moon!” he continues. “The Moon is a large mysterious world in its own right, and its only three days away! I would love to land on an IMP and take the Moon’s temperature first-hand using a heat probe.”

    Some people think the Moon looks dead, “but I never thought so,” says Robinson, who won’t rule out the possibility of future eruptions. “To me, it has always been an inviting place of magnificent beauty, a giant magnet in our sky drawing me towards it.”

    Young volcanoes have only turned up the heat on the Moon’s allure. Says Robinson … “let’s go!”

    See the full article here.

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    The National Aeronautics and Space Administration (NASA) is the agency of the United States government that is responsible for the nation’s civilian space program and for aeronautics and aerospace research.

    President Dwight D. Eisenhower established the National Aeronautics and Space Administration (NASA) in 1958 with a distinctly civilian (rather than military) orientation encouraging peaceful applications in space science. The National Aeronautics and Space Act was passed on July 29, 1958, disestablishing NASA’s predecessor, the National Advisory Committee for Aeronautics (NACA). The new agency became operational on October 1, 1958.

    Since that time, most U.S. space exploration efforts have been led by NASA, including the Apollo moon-landing missions, the Skylab space station, and later the Space Shuttle. Currently, NASA is supporting the International Space Station and is overseeing the development of the Orion Multi-Purpose Crew Vehicle and Commercial Crew vehicles. The agency is also responsible for the Launch Services Program (LSP) which provides oversight of launch operations and countdown management for unmanned NASA launches. Most recently, NASA announced a new Space Launch System that it said would take the agency’s astronauts farther into space than ever before and lay the cornerstone for future human space exploration efforts by the U.S.

    NASA science is focused on better understanding Earth through the Earth Observing System, advancing heliophysics through the efforts of the Science Mission Directorate’s Heliophysics Research Program, exploring bodies throughout the Solar System with advanced robotic missions such as New Horizons, and researching astrophysics topics, such as the Big Bang, through the Great Observatories [Hubble, Chandra, Spitzer, and associated programs. NASA shares data with various national and international organizations such as from the Greenhouse Gases Observing Satellite.

     
  • richardmitnick 9:13 pm on November 24, 2014 Permalink | Reply
    Tags: , , , , Astrophysics,   

    From ALMA via ESO: “Seeing into the Heart of Mira A and its Partner” 

    ALMA Array
    ALMA

    NRAO Small

    ESO 50

    NAOJ


    European Southern Observatory

    Studying red giant stars tells astronomers about the future of the Sun — and about how previous generations of stars spread the elements needed for life across the Universe. One of the most famous red giants in the sky is called Mira A, part of the binary system Mira which lies about 400 light-years from Earth. In this image ALMA reveals Mira’s secret life.

    Mira A is an old star, already starting to throw out the products of its life’s work into space for recycling. Mira A’s companion, known as Mira B, orbits it at twice the distance from the Sun to Neptune.

    m
    ESO/S. Ramstedt (Uppsala University, Sweden) & W. Vlemmings (Chalmers University of Technology, Sweden)

    Mira A is known to have a slow wind which gently moulds the surrounding material. ALMA has now confirmed that Mira’s companion is a very different kind of star, with a very different wind. Mira B is a hot, dense white dwarf with a fierce and fast stellar wind.

    New observations show how the winds from the two stars have created a fascinating, beautiful and complex nebula. The remarkable heart-shaped bubble at the centre is created by Mira B’s energetic wind inside Mira A’s more relaxed outflow. The heart, which formed some time in the last 400 years or so, and the rest of the gas surrounding the pair show that they have long been building this strange and beautiful environment together.

    By looking at stars like Mira A and Mira B scientists hope to discover how our galaxy’s double stars differ from single stars in how they give back what they have created to the Milky Way’s stellar ecosystem. Despite their distance from one another, Mira A and its companion have had a strong effect on one another and demonstrate how double stars can influence their environments and leave clues for scientists to decipher.

    Other old and dying stars also have bizarre surroundings, as astronomers have seen using both ALMA and other telescopes. But it’s not always clear whether the stars are single, like the Sun, or double, like Mira. Mira A, its mysterious partner and their heart-shaped bubble are all part of this story.

    The new observations of Mira A and its partner are presented in this paper.

    See the full article here.

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    ESO, European Southern Observatory, builds and operates a suite of the world’s most advanced ground-based astronomical telescopes.

     
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