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  • richardmitnick 6:09 pm on November 20, 2015 Permalink | Reply
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    From SPACE.com: “Stellar Graveyard Reveals Clues About Milky Way’s Ancient Birth” 

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    November 19, 2015
    Nola Taylor Redd

    By studying the motion of stars over nearly a decade in the Hubble SWEEPS Field, shown here, scientists have been able to better understand the early years of the Milky Way.

    An image of the heart of the Milky Way shows the location of ancient white dwarfs. At left is a ground-based image of the galaxy’s central bulge; the upper right shows a small section of Hubble’s view of this region, while the lower-right image.

    NASA’s Hubble Space Telescope has peered far back in time, detecting clues about how the Milky Way galaxy came together, shortly after the universe’s birth.

    NASA Hubble Telescope
    NASA/ESA Hubble

    Astronomers trained Hubble on the Milky Way’s dense central bulge and spotted a population of superdense stellar corpses called white dwarfs that are remnants of stars that formed about 12 billion years ago. These stars are archaeological evidence of the first few billion years of the galaxy’s history, researchers said.

    “It is important to observe the Milky Way’s bulge, because it is the only bulge we can study in detail,” study lead author Annalisa Calamida, of the Space Telescope Science Institute (STScI) in Baltimore, Maryland, said in a statement. “You can see bulges in distant galaxies, but you cannot resolve the very faint stars, such as the white dwarfs.”

    Like other spiral galaxies, the Milky Way harbors a dense central bulge surrounded by wispy spiral arms. Scientists think that such bulges formed first, while the outer arms came later.

    “The Milky Way’s bulge includes almost a quarter of the galaxy’s stellar mass,” Calamida said. “Characterizing the properties of the bulge stars can then provide important ways to understand the formation of the entire Milky Way galaxy and that of similar, more-distant galaxies.”

    But studying the Milky Way’s core is a challenge; Earth’s sun orbits on one of the outlying arms, with stars lying between Earth and the galaxy’s star-packed heart.

    Using Hubble, the team studied the motion of about 240,000 Milky Way stars over nearly a decade. By comparing how the positions of these stars changed over that time, the researchers were able to pick out 70,000 that inhabit the bulge.

    The team found that the galactic center contains slightly more low-mass stars compared to the outskirts.

    “These results suggest that the environment in the bulge may have been different than the one in the disk, resulting in different star-formation mechanisms,” Calamida said.

    The astronomers also identified 70 white dwarfs in the bulge sample, by comparing the stars’ colors to those predicted for white dwarfs by theoretical models. Finding white dwarfs is no small feat; since these corpses no longer undergo fusion, they are quite dim. Indeed, NASA officials compared isolating a white dwarf from the background to searching for the glow of a pocket flashlight held by an astronaut on the moon.

    But studying white dwarfs is worth the effort, the researchers said. Doing so can reveal information about the stars that built the Milky Way’s core nearly 12 billion years ago, researchers said. (For comparison, the universe is approximately 13.8 billion years old.)”These 70 white dwarfs represent the peak of the iceberg,” study leader Kailash Sahu, also of STScI, said in the same statement. “We estimate that the total number of white dwarfs is about 100,000 in this tiny Hubble view of the bulge.”

    With Hubble pushing the limits of what can be seen, it will fall to other instruments to capture even fainter stars, Sahu said.

    “Future telescopes such as NASA’s James Webb Space Telescope will allow us to count almost all of the stars in the bulge, down to the faintest ones, which today’s telescopes, even Hubble, cannot see,” Sahu said.

    NASA Webb Telescope

    The researchers said they intend to analyze other portions of the same field of sky, ultimately leading to a more precise estimate for the age of the galactic heart.

    The results were published in September in the Astrophysical Journal.

    See the full article here .

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  • richardmitnick 7:43 pm on November 19, 2015 Permalink | Reply
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    From SPACE.com: “Einstein’s Unfinished Dream: Marrying Relativity to the Quantum World” 

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    November 18, 2015
    FNAL Don Lincoln
    Don Lincoln, Senior Scientist, Fermi National Accelerator Laboratory; Adjunct Professor of Physics, University of Notre Dame

    This artist’s illustration depicts how the foamy structure of space-time may appear, showing tiny bubbles quadrillions of times smaller than the nucleus of an atom that are constantly fluctuating and last for only infinitesimal fractions of a second. Credit: NASA/CXC/M.Weiss

    This November marks the centennial of Albert Einstein’s theory of general relativity. This theory was the crowning achievement of Einstein’s extraordinary scientific life. It taught us that space itself is malleable, bending and stretching under the influence of matter and energy. His ideas revolutionized humanity’s vision of the universe and added such mind-blowing concepts as black holes and wormholes to our imagination.

    Einstein’s theory of general relativity describes a broad range of phenomena, from nearly the moment of creation to the end of time, and even a journey spiraling from the deepest space down into a ravenous black hole, passing through the point of no return of the event horizon, down, down, down, to nearly the center, where the singularity lurks.

    Deep into a quantum world

    If you were reading that last paragraph carefully, you’ll note that I used the word “nearly” twice. And that wasn’t an accident. Einstein’s theory has been brilliantly demonstrated at large size scales. It deftly explains the behavior of orbiting binary pulsars and the orbit of Mercury. It is a crucial component of the GPS system that helps many of us navigate in our cars every day.

    But the beginning of the universe and the region near the center of a black hole are very different worlds — quantum worlds. The size scales involved in those environments are subatomic. And that’s where the trouble starts.

    Einstein’s heyday coincided with the birth of quantum mechanics, and the stories of his debates with physicist Niels Bohr over the theory’s counterintuitive and probabilistic predictions are legendary. “God does not play dice with the universe,” he is famously reported to have said.

    However, regardless of his disdain for the theory of quantum mechanics, Einstein was well aware of the need to understand the quantum realm. And, in his quest to understand and explain general relativity, he sought to understand how of gravity performed in his epic theory when it was applied to the world of the supersmall. The result can be summarized in three words: It failed badly.

    download the mp4 video here.

    Bridging the quantum world to relativity

    Einstein spent the rest of his life, without success, pursuing ways to integrate his theory of general relativity with quantum mechanics. While it is tempting to describe the history of this attempt, the effort is of interest primarily to historians. After all, he didn’t succeed, nor did anyone in the decades that followed.

    Instead, it is more interesting to get a sense of the fundamental problems associated with wedding these two pivotal theories of the early 20th century. The initial issue was a systemic one: General relativity uses a set of differential equations that describe what mathematicians call a smooth and differentiable space. In layman’s terms, this means that the mathematics of general relativity is smooth, without any sharp edges.

    In contrast, quantum mechanics describes a quantized world, e.g. a world in which matter comes in discrete chunks. This means that there is an object here, but not there. Sharp edges abound.

    The water analogy

    In order to clarify these different mathematical formulations, one need think a bit more deeply than usual about a very familiar substance we know quite well: liquid water. Without knowing it, you already hold two different ideas about water that illustrate the tension between differential equations and discrete mathematics.

    For example, when you think of the familiar experience of running your hand through water, you think of water as a continuous substance. The water near your hand is similar to the water a foot away. That distant water might be hotter or colder or moving at a different speed, but the essence of water is the same. As you consider different volumes of water that get closer and closer to your hand, your experience is the same. Even if you think about two volumes of water separated by just a millimeter or half a millimeter, the space between them consists of more water. In fact, the mathematics of fluid flow and turbulence assumes that there is no smallest, indivisible bit of water. Between any two arbitrarily-close distances, there will be water. The mathematics that describes this situation is differential equations. Digging down to its very essence, you find that differential equations assume that there is no smallest distance.

    But you also know that this isn’t true. You know about water molecules. If you consider distances smaller than about three angstroms (the size of a water molecule), everything changes. You can’t get smaller than that, because when you probe even smaller distances, water is no longer a sensible concept. At that point, you’re beginning to probe the empty space inside atoms, in which electrons swirl around a small and dense nucleus. In fact, quantum mechanics is built around the idea that there are smallest objects and discrete distances and energies. This is the reason that a heated gas emits light at specific wavelengths: the electrons orbit at specific energies, with no orbits between the prescribed few.

    Thus a proper quantum theory of water has to take into account the fact that there are individual molecules. There is a smallest distance for which the idea of “water” has any meaning.

    Thus, at the very core, the mathematics of the two theories (e.g. the differential equations of general relativity and the discrete mathematics of quantum mechanics) are fundamentally at odds.

    download the mp4 video here.

    Can the theories merge?

    This is not, in and of itself, an insurmountable difficulty. After all, parts of quantum mechanics are well described by differential equations. But a related problem is that when one tries to merge the two theories, infinities abound; and when an infinity arises in a calculation, this is a red flag that you have somehow done something wrong.

    As an example, suppose you treat an electron as a classical object with no size and calculate how much energy it takes to bring two electrons together. If you did that, you’d find that the energy is infinite. And infinite to a mathematician is a serious business. That’s more energy than all of the energy emitted by all of the stars in the visible universe. While that energy is mind-boggling in its scale, it isn’t infinite. Imagining the energy of the entire universe concentrated in a single point is just unbelievable, and infinite energy is much more than that.

    Therefore, infinities in real calculations are a clear sign that you’ve pushed your model beyond the realm of applicability and you need to start looking to find some new physical principles that you’ve overlooked in your simplified model.

    In the modern day, scientists have tried to solve the same conundrum that so flummoxed Einstein. And the reason is simple: The goal of science is to explain all of physical reality, from the smallest possible objects to the grand vista of the cosmos.

    The hope is to show that all matter originates from a small number of building blocks (perhaps only one) and a single underlying force from which the forces we currently recognize originates. Of the four known fundamental forces of nature, we have been able to devise quantum theories of three: electromagnetism, the strong nuclear force, and the weak nuclear forces. However, a quantum theory of gravity has eluded us.

    General relativity is no doubt an important advance, but until we can devise a quantum theory of gravity, there is no hope of devising a unified theory of everything. While there is no consensus in the scientific community on the right direction in which to proceed, there have been some ideas that have had limited success.

    Superstring theory

    The best-known theory that can describe gravity in the microworld is called superstring theory. In this theory, the smallest known particles should not be thought of as little balls, but rather tiny strings, kind of like an incredibly small stick of uncooked spaghetti or a micro-miniature Hula-Hoop. The basic idea is that these tiny strings (which are smaller compared to a proton than a proton is compared to you) vibrate, and each vibration presents a different fundamental particle.

    Employing a musical metaphor, an electron might be an A-sharp, while a photon could be a D-flat. In the same way that a single violin string can have many overtones, the vibrations of a single superstring can be different particles. The beauty of superstring theory is that it allows for one of the vibrations to be a graviton, which is a particle that has never been discovered but is thought to be the particle that causes gravity.

    It should be noted that superstring theory is not generally accepted, and indeed, some in the scientific community don’t even consider it to be a scientific theory at all. The reason is that, in order for a theory to be scientific, it must be able to be tested, and have the potential to be proven wrong. However, the very small scale of these theoretical strings makes it difficult to imagine any tests that could be done in the foreseeable future. And, some say, if you can’t realistically do a test, it isn’t science.

    Personally, I think that is an extreme opinion, as one can imagine doing such a test when technology advances. But that time will be far in the future.

    Another idea for explaining quantum gravity is called loop quantum gravity. This theory actually quantizes space-time itself. In other words, this model says that there is a smallest bit of space and a shortest time. This provocative idea suggests, among other things, that the speed of light might be different for different wavelengths. However, this effect, if it exists, is small and requires that light travel for great distances before such differences could be observed. Toward that end, scientists are looking at gamma-ray bursts, explosions so bright that they can be seen across billions of light-years — an example of the cosmic helping scientists study the microscopic.

    The simple fact is that we don’t yet have a good and generally accepted theory of quantum gravity. The question is simply just too difficult, for now. The microworld of the quantum and the macroworld of gravity have long resisted a life of wedded bliss and, at least for the moment, they continue to resist. However, scientists continue to find the linkage that blends the two. In the meantime, a theory of quantum gravity remains one of the most ambitious goals of modern science — the hope that we will one day fulfill Einstein’s unfinished dream.

    See the full article here .

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  • richardmitnick 7:49 pm on November 16, 2015 Permalink | Reply
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    From SPACE.com: “Exoplanet’s Global Winds Let Rip at 5,400 MPH” 

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    November 16, 2015
    Irene Klotz

    A windy day on HD 189733b is nothing to take lightly. Credit: Mark A. Garlick/University of Warwick

    The planet, located about 63 light years away in the constellation Vulpecula, has winds reaching 5,400 mph, roughly 20 times faster than anything ever experienced on Earth.

    Granted, everything about HD 189733b is extreme. It’s about 10 percent bigger than Jupiter, but its located 180 times closer to its parent star than Jupiter is to the sun, far closer than even Mercury, the innermost planet in the solar system.

    Scientists estimate its temperature reaches almost 3,700 degrees Fahrenheit.

    HD 189733b orbits its host start every 2.2 days, at a breakneck speed of 341,000 mph.

    Scientists at the University of Warwick were able to measure velocities on the day and night sides of the planet. They discovered the 5,400 mph wind blowing from the day to the night side.

    “As parts of HD 189733b’s atmosphere move towards or away from the Earth the Doppler effect changes the wavelength of this feature, which allows the velocity to be measured,” lead researcher Tom Louden said in a statement. “This is the first ever weather map from outside of our solar system.”

    Astronomers used HARPS, the High Accuracy Radial velocity Planet Searcher, in La Silla, Chile, to watch the planet as it passed in front of its host star, relative to the telescope’s line of sight.

    ANALYSIS: Exoplanet Weather Forecast: Hot and Nasty

    “The surface of the star is brighter at the center than it is at the edge, so as the planet moves in front of the star the relative amount of light blocked by different parts of the atmosphere changes. For the first time we’ve used this information to measure the velocities on opposite sides of the planet independently, which gives us our velocity map,” Louden said.

    The research is being published in the Astrophysical Journal Letters.

    See the full article here .

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  • richardmitnick 8:37 am on November 10, 2015 Permalink | Reply
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    From SPACE.com: “Gigantic* New Telescope Breaking Ground in Chile This Week” 

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    November 09, 2015
    Mike Wall

    Artist’s illustration of the Giant Magellan Telescope (GMT), which will be built atop Las Campanas Peak in Chile. The groundbreaking ceremony for GMT, which will feature seven mirrors arranged to form a light-collecting surface 80 feet (24 meters) wide, is scheduled for Nov. 11, 2015.Credit: Giant Magellan Telescope – GMTO Corporation

    Construction will begin this week on a giant new telescope in the mountains of Chile, and Space.com will be there to take in the milestone moment.

    The groundbreaking ceremony for the Giant Magellan Telescope (GMT) — a huge instrument that astronomers will use to hunt for signs of life in the atmospheres of alien planets, probe the nature of dark energy and dark matter, and tackle other big cosmic questions — is scheduled to occur Wednesday (Nov. 11) at the Las Campanas Observatory in the Chilean Andes.

    The Giant Magellan Telescope Organization invited Space.com Senior Writer Mike Wall to attend the event, and he will provide coverage from onsite.

    When it’s finished, the GMT will consist of seven 27.6-foot-wide (8.4 meters) primary mirrors — the largest single-piece astronomical mirrors ever made — arranged into one light-collecting surface 80 feet (24 m) across, as well as seven smaller secondary mirrors that will change shape to counteract the blurring effects of Earth’s atmosphere. The finished observatory will boast about 10 times the resolving power of NASA’s famous Hubble Space Telescope, GMT officials have said**.

    Four of the 20-ton primary mirrors have already been cast, at the University of Arizona’s Steward Observatory Mirror Lab. All four should be fully polished (a time-consuming, exacting task) and delivered to Las Campanas by late 2021, allowing the telescope to begin science operations around that time, said GMT director Pat McCarthy.

    “That will give us the world’s largest telescope by more than a factor of two at that point,” McCarthy told Space.com in September, shortly after the casting of the fourth mirror had been completed.

    Primary mirrors number five, six and seven will probably be installed at the rate of about one per year after that, bringing the GMT up to full strength around 2024 or so, he added.

    Two other megascopes should also be coming online at about that time — the Thirty Meter Telescope (TMT) in Hawaii and the European Extremely Large Telescope (E-ELT), which, like GMT, will view the heavens from the Chilean Andes. TMT and E-ELT will combine hundreds of relatively small mirrors to form light-collecting surfaces that measure 98 feet (30 m) and 128 feet (39 m) wide, respectively.



    These three enormous ground-based observatories — along with NASA’s James Webb Space Telescope, which is scheduled to launch in late 2018 — should usher in a sort of astronomy golden age, McCarthy said.

    NASA James Webb Telescope

    “About seven to 10 years from now, there will be observational capabilities that are completely unprecedented,” he said. “I expect we will make a big leap in our understanding [of the cosmos], but I also suspect that we’ll find out that some of the things that we believe now turn out not to be quite correct. Often in science, the more you learn, the more you realize that there’s a lot to learn.”

    • I think that the writer is being over generous here. The GMT will be a 24 meter telescope. The ESO E-ELT will be a 39 meter telescope. The Caltech/UCO/DST/NAOC/NAOJ/NRC/ Thirty Meter Telescope will be just that, 30 meters.

    **This is a silly comparison. Ground based and space based observatories have not a lot in common.

    See the full article here .

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  • richardmitnick 7:08 am on October 27, 2015 Permalink | Reply
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    From SPACE.com: “Get Lost in This Jaw-Dropping View of the Eagle Nebula” 

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    October 26, 2015
    Calla Cofield

    The Pillars of Creation can be seen in this highly detailed view of the Eagle Nebula. Credit: Terry Hancock http://www.downunderobservatory.com, Gordon Wright, Colin Cooper, Kim Quick.

    It’s easy to get lost in this jaw-dropping snapshot of the Eagle Nebula, which offers a high-resolution view of an incredible space landscape.

    The Eagle Nebula is a massive collection of gas and dust, which serves as fertile soil for the birth of new stars. The blue, lagoonlike region at the center of the image contains the iconic, fingerlike structures known as the Pillars of Creation. The blue, green and red indicate the presence of different gasses.

    The image was created by a collaboration of four astrophotographers, and is composed of 177 individual frames, with a total integration time of 32 hours. The group members are Terry Hancock of Michigan (whose sky images have been featured on Space.com many times before), Gordon Wright from Scotland, Colin Cooper, Spain; and Kim Quick, Florida. The full-size image is almost too much to take in all at once, so viewers are encouraged to zoom in [?] and get lost in the details of this incredible snapshot.

    The Eagle Nebula is about 7,000 light-years from Earth, and is approximately 70 light-years tall and 55 light-years wide. (One light-year is the distance light travels in a year, about 6 trillion miles, or 10 trillion kilometers). The blue in the image shows the presence of ionized oxygen (meaning oxygen atoms that have lost electrons), green shows the presence of hydrogen, and red, ionized sulfur.

    The Pillars of Creation were first captured in a stunning image by the Hubble Space Telescope in 1995 and again, in higher resolution, in 2014. The Pillars were likely an active bed of star formation at one time, but scientists have recently observed very low levels of X-ray light coming from the region, suggesting that star formation has slowed.


    The Eagle Nebula and the Star Queen nebula can be seen in this annotated view. Credit: Terry Hancock http://www.downunderobservatory.com, Gordon Wright, Colin Cooper, Kim Quick.

    From space.com, “Hubble Telescope Captures Spectacular New Views of ‘Pillars of Creation'”, Nola Taylor Redd, January 06, 2015

    The Hubble Space Telescope has taken a fresh look at the iconic Pillars of Creation in the Eagle Nebula 6,500 light-years from Earth, revealing the most detailed view yet of a feature Hubble originally discovered 20 years ago. The new image was taken to commemorate Hubble’s 25th anniversary in 2015.
    Credit: NASA, ESA/Hubble and the Hubble Heritage Team

    An infrared view of the Eagle Nebula reveals many of the stars at the heart of its pillars. Credit: NASA, ESA/Hubble and the Hubble Heritage Team

    NASA Hubble Telescope
    NASA/ESA Hubble

    See the full article here .

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  • richardmitnick 4:59 am on October 27, 2015 Permalink | Reply
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    From SPACE.com: “Milky Way Glitters in Most Enormous Astronomical Image Ever” 

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    October 22, 2015
    Sarah Lewin

    A section of the new Milky Way drawn from what researchers say is the largest astronomical image ever compiled.
    Credit: Lehrstuhl für Astrophysik, RUB/http://gds.astro.rub.de/

    A new, insanely massive picture of the Milky Way — 46 billion pixels across — marks the largest astronomical image of all time, researchers say. It’s so big, it we can only show part of it on this page.

    The amazing view of the Milky Way was built out of 268 individual views of the galaxy that includes the sun and the Earth, captured night after night over the course of five years with telescopes in Chile’s Atacama Desert. Astronomers at Ruhr-Universität Bochum used the data to examine stars whose brightness changes over time — and the image portrays more than 50,000 new objects with variable brightness that have never been recorded before.

    The researchers made the zoom-able, searchable image available their website, so galactic explorers can scroll across the Milky Way and examine its famous and lesser-known features with more detail than ever before.

    A section of a new, 46-billion-pixel image of the Milky Way shows the star system Eta Carinae. Credit: Lehrstuhl für Astrophysik, RUB

    The researchers photographed every one of the 268 areas of the sky “in intervals of several days” over the course of the 5 years, the researchers said in a statement. And once they had them all, they were incorporated during a several-week calculation period.

    The lead author of the new work, Moritz Hackstein, needed this incredible level of detail to pinpoint how stars were changing in the sky: Stars with planets orbiting them or systems with multiple stars will vary from brighter to dimmer during different parts of the orbit, for instance, and some stars intrinsically pulse brighter and dimmer or ignite into supernovas.

    To identify any changes to the Milky Way’s stars, multiple photos have to be taken over time and compared. The researchers found 64,151 variable sources of light in total — and 56,794 of them had never been seen before.

    See the full article here .

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  • richardmitnick 4:27 pm on September 9, 2015 Permalink | Reply
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    From SPACE.com: ” ‘Cosmic Tsunami’ Shocks Comatose ‘Sausage’ Galaxy Cluster Into Star Formation” 

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    September 09, 2015
    Elizabeth Howell

    This radio image shows a shock wave (the bright arc running from bottom left to top right) in the ‘Sausage’ merging cluster of galaxies as seen by the Giant Metrewave Radio Telescope. The shock wave was generated 1 billion years ago, when the two original clusters collided, and is moving at 5.6 million mph (9 million km/h). Credit: Andra Stroe

    Giant Metrewave Radio Telescope
    Giant Metrewave Radio Telescope

    A so-called “cosmic tsunami” is rousing a galaxy cluster affectionately nicknamed “Sausage,” suggesting that stagnant galaxies can be rejuvenated when galactic clusters collide, scientists say.

    Astronomers made the discovery while studying CIZA J2242.8+5301, an ancient galaxy cluster 2.3 billion light-years from Earth. The cluster (yes, they actually call it Sausage), which is full of old red stars, is waking up as a shock wave triggers new star formation. The shock wave from the cluster’s collision, which scientists compared to a tsunami, began 1 billion years ago and is moving at a mind-boggling speed: 5.6 million mph (9 million km/h).

    “We assumed that the galaxies would be on the sidelines for this act, but it turns out they have a leading role,” study co-leader Andra Stroe, an astronomer at Leiden Observatory, said in a statement. “The comatose galaxies in the Sausage cluster are coming back to life, with stars forming at a tremendous rate. When we first saw this in the data, we simply couldn’t believe what it was telling us.”

    This is the first time such star formation has been observed, but in theory nearly every galaxy cluster should have passed through this period of furious star formation. Alas, such a resurrection is not meant to last, the researchers said.

    “But star formation at this rate leads to a lot of massive, short-lived stars coming into being, which explode as supernovae a few million years later,” the study’s other co-leader, David Sobral of Leiden and the University of Lisbon, said in a statement. “The explosions drive huge amounts of gas out of the galaxies and with most of the rest consumed in star formation, the galaxies soon run out of fuel. If you wait long enough, the cluster mergers make the galaxies even more red and dead — they slip back into a coma and have little prospect of a second resurrection.”

    This composite image of the ‘Sausage’ merging galaxy cluster CIZA J2242.8+5310 was made using data from the Subaru and Canada France Hawaii Telescopes (CFHT).

    NAOJ Subaru Telescope
    NAOJ Subaru Telescope interior
    NAOJ Subaru

    CFHT Telescope
    CFHT Interior

    The white circles indicate galaxies outside of the cluster, while yellow circles are cluster galaxies, where accelerated star formation is taking place. Green hues trace out shock waves and purple marks hot X-ray-emitting gas between the galaxies that emits X-rays. Credit: Andra Stroe

    Stroe, Sobal and an international team of astronomers used several telescopes and observatories in La Palma, Spain, and in Hawaii to study the Sausage galaxy cluster, which is located in the constellation Lacerta (the Lizard) in the Northern Hemisphere sky. Their research was detailed in the April 24 edition of the Monthly Notices of the Royal Astronomical Society.

    The team plans to sample a larger number of galaxies soon to try to catch more of these comatose mergers in the act.

    See the full article here .

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  • richardmitnick 12:06 pm on August 28, 2015 Permalink | Reply
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    From SPACE.com: “How to Find ‘Strange Life’ on Alien Planets” 

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    August 28, 2015
    Nola Taylor Redd

    This artist’s rendition of the super-Earth GJ 1214b shows it in orbit around a dim red dwarf star. If the atmosphere is thick in hydrogen, scientists may be able to spot signs of alien life. Credit: CfA/David Aguilar

    Detecting signs of life very different from that of Earth in the atmospheres of alien planets may be difficult, but it is possible, researchers say.

    A team of scientists examined models of “super-Earths” — exoplanets slightly larger than Earth — to determine how easily signs of life could be spotted. They determined that such biosignatures could be identified more easily on planets orbiting stars producing relatively low amounts of radiation — but even then only if everything worked out just right.

    The team, led by Sara Seager of the Massachusetts Institute of Technology (MIT), did not focus solely on Earth-like life.

    “What we’ve been trying to do is move away from that,” William Bains, also of MIT, said during the Astrobiology Science Conference in Chicago in June. Bains worked with Seager and Renyu Hu to study super-Earths with hydrogen-rich atmospheres. “We wanted to build a model of biosignatures independent of Earth’s biology.”

    ‘A dynamic process’

    Super-Earths are worlds up to 10 times more massive than our planet. Because of their size, they are more likely to retain an atmosphere rich in molecular hydrogen. The girth of super-Earths also makes them easier to discover, and their atmospheres easier to characterize, relative to their Earth-size cousins. Hydrogen-rich super-Earths are now known to be quite common throughout the galaxy.

    Bains and his colleagues simulated a planet 10 times as massive and nearly twice as wide as Earth, with an atmosphere rich in molecular hydrogen. Their simulations placed the planet in an orbit around three different types of stars: a sunlike star, a normal red dwarf (a star smaller and dimmer than the sun) and and an especially inactive red dwarf. (Different stellar types produce different levels of ultraviolet radiation, with the sunlike star producing the most, which affects how molecules break down in the atmosphere of orbiting planets.)

    To search for biosignatures, Bains said, it’s important to understand why forms of life produce gas in the first place. Some gas is produced as a byproduct when energy is captured from the atmosphere. Other gases are byproducts of metabolic reactions, such as photosynthesis. The third type is created by life not as a result of its central chemical production but from stress, for signaling and in other functions.

    “Life is a dynamic process,” Bains said.

    The byproducts of life

    After determining what gases could survive in the atmosphere, the scientists then calculated how much biomass would be needed to produce a detectable amount, and whether or not such an amount of life would be reasonable to find.

    The team found four volatiles that would be generated by the production of energy in a hydrogen-rich atmosphere. Of them, three could be formed geologically, making them unreliable biosignatures.

    “This was really disappointing,” Bains said.

    The only interesting biosignature that the team came up in the first class was ammonia (NH3). For ammonia to be created, life would have to find a way to break the bonds between molecular nitrogen and molecular hydrogen. On Earth, synthetic chemistry can break each molecule apart individually, but no known system is capable of breaking both at once. Still, the team remains hopeful that a form of life could evolve on other worlds capable of capitalizing on the possibility.

    Producing a detectable amount of ammonia in the atmosphere of a distant super-Earth would require a layer of life less than one bacterial cell thick, researchers said.

    “Even if it was deader than the deadest place on Earth, we could detect it,” Bains said.

    That’s the case for super-Earths orbiting sunlike stars, anyway. For alien planets receiving lower levels of ultraviolet radiation, such as those orbiting standard or quiet red dwarfs, the required biomass would need to be significantly higher.

    While scientists should be able to detect ammonia in the atmosphere of distant planets, determining if it stems from life is another matter. At present, uncertainties about the size and mass of exoplanets remain high enough that worlds presently thought to be super-Earths could, in fact, be mini-Neptunes, gas giants smaller than those found in the solar system.

    Disregarding the fact that surface conditions on gas planets would be essentially nonexistent, the deep atmospheres could produce ammonia without the aid of life. Determining whether a planet is a super-Earth or a mini-Neptune requires probing atmospheric pressures near the surface, something that even NASA’s upcoming James Webb Space Telescope [JWST] will be unable to accomplish, researchers said.

    NASA Webb Telescope

    Even if scientists could conclusively identify a planet as rocky, it’s possible that the world could have collected ammonia during its evolution, as Saturn’s moon, Titan, did. Ices on the surface could break down with either internal heat or with the help of ultraviolet radiation, releasing ammonia into the atmosphere to create a false positive.

    So, without getting up close to these distant worlds, characterizing whether ammonia in the atmosphere comes from life remains a significant challenge.

    The research that formed the basis of Bains’ talk at the astrobiology conference was published in late 2013 in The Astrophysical Journal.

    ‘In our favor’

    Seager, Bains and Hu also considered another group of gases — those produced for biomass building. Capturing energy from the environment requires energy. On Earth, a prime example is the oxygen plants release during the process of photosynthesis.

    Unfortunately, the team was unable to identify any potentially useful biosignature gases of this type in a hydrogen-rich atmosphere. The gases that life might produce would be expected to exist naturally in the atmosphere of such a world, Bains said.

    As a third option, the team examined molecules produced unrelated to energy generation. The presence of such gases would depend on the amount of ultraviolet (UV) radiation in the atmosphere, because high UV levels lead to the creation of lots of destructive hydrogen ions.

    Planets orbiting sunlike stars, which emit lots of UV light, would therefore need an enormous density of biomass to produce biosignatures high enough to reach detectable levels. Even around a normal red dwarf, the values would need to be high, though they could be plausible when compared to Earth’s biomass surface density range.

    According to the team, the James Webb Space Telescope (JWST) could spot evidence of biosignatures gas “if and only if every single factor is in our favor.”

    Detecting life using JWST would require a pool of transiting planets around nearby red dwarfs. Because the stars are so dim, they would need to be relatively close to Earth in order for scientists to study their planets. These planets would need a molecular hydrogen atmosphere, which would be easier to study than a more Earth-like atmosphere. The star itself would need to be quiet, with little radiation. Finally, the planet itself must have life that produces a detectable gas as a biosignature.

    “We will have the ability to predict some biosignatures gas independent of Earth,” Bains said. “But it’s going to be really hard to detect.”

    See the full article here.

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  • richardmitnick 11:13 am on August 28, 2015 Permalink | Reply
    Tags: , , , space.com   

    From SPACE.com- ” Incredible Technology: How to See a Black Hole” Very Old, But Very Worth Your Time 

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    July 08, 2013
    Clara Moskowitz

    Theoretical calculations predict that the Milky Way’s central black hole, called Sagittarius A*, will look like this when imaged by the Event Horizon Telescope. The false-color image shows light radiated by gas swirling around and into a black hole. The dark region in the middle is the “black hole shadow,” caused by the black hole bending light around it.
    Credit: Dexter, J., Agol, E., Fragile, P. C., McKinney, J. C., 2010, The Astrophysical Journal, 717, 1092.

    Black holes are essentially invisible, but astronomers are developing technology to image the immediate surroundings of these enigmas like never before. Within a few years, experts say, scientists may have the first-ever picture of the environment around a black hole, and could even spot the theorized “shadow” of a black hole itself.

    Black holes are hard to see in detail because the large ones are all far away. The closest supermassive black hole is the one thought to inhabit the center of the Milky Way, called Sagittarius A* (pronounced “Sagittarius A-star”), which lies about 26,000 light-years away.

    Sagittarius A*. This image was taken with NASA’s Chandra X-Ray Observatory. Ellipses indicate light echoes.
    Date 23 July 2014

    NASA Chandra Telescope

    This is the first target for an ambitious international project to image a black hole in greater detail than ever before, called the Event Horizon Telescope (EHT).

    Event Horizon Telescope
    Event Horizon Telescope map
    EHT and EHT Map

    The EHT will combine observations from telescopes all over the world, including facilities in the United States, Mexico, Chile, France, Greenland and the South Pole, into one virtual image with a resolution equal to what would be achieved by a single telescope the size of the distance between the separated facilities.

    “This is really an unprecedented, unique experiment,” said EHT team member Jason Dexter, an astrophysical theorist at the University of California, Berkeley. “It’s going to give us more direct information than we’ve ever had to understand what happens extremely close to black holes. It’s very exciting, and this project is really going to come of age and start delivering amazing results in the next few years.”

    From Earth, Sagittarius A* looks about as big as a grapefruit would on the moon. When the Event Horizon Telescope is fully realized, it should be able to resolve details about the size of a golf ball on the moon. That’s close enough to see the light emitted by gas as it spirals in toward its doom inside the black hole.

    Very long baseline interferometry

    To accomplish such fine resolution, the project takes advantage of a technique called very long baseline interferometry (VLBI). In VLBI, a supercomputer acts as a giant telescope lens, in effect.

    “If you have telescopes around the world you can make a virtual Earth-sized telescope,” said Shep Doeleman, an astronomer at MIT’s Haystack Observatory in Massachusetts who’s leading the Event Horizon Telescope project. “In a typical telescope, light bounces off a precisely curved surface and all the light gets focused into a focal plane. The way VLBI works is, we have to freeze the light, capture it, record it perfectly faithfully on the recording system, then shift the data back to a central supercomputer, which compares the light from California and Hawaii and the other locations, and synthesizes it. The lens becomes a supercomputer here at MIT.”

    A major improvement to the Event Horizon Telescope’s imaging ability will come when the 64 radio dishes of the ALMA (Atacama Large Millimeter/submillimeter Array) observatory in Chile join the project in the next few years.

    ALMA Array
    ALMA Array

    “It’s going to increase the sensitivity of the Event Horizon Telescope by a factor of 10,” Doeleman said. “Whenever you change something by an order of magnitude, wonderful things happen.”

    Very long baseline interferometry has been used for about 50 years, but never before at such a high frequency, or short wavelength, of light. This short-wavelength light is what’s needed to achieve the angular resolution required to measure and image black holes.

    South Pole Telescope [SPT]

    The South Pole Telescope will join the Event Horizon Telescope project in coming years to image the area around the black hole at the center of the Milky Way.

    South Pole Telescope

    Grand technical challenge

    Pulling off the Event Horizon Telescope has been a grand technical challenge on many fronts.

    To coordinate the observations of so many telescopes spread out around the world, scientists have needed to harness specialized computing algorithms, not to mention powerful supercomputers. Plus, to accommodate the time difference between the various stations, extremely accurate clocks are needed.

    See the full article here.

    Event Horizon Telescope
    Event Horizon Telescope Science

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  • richardmitnick 5:37 pm on August 22, 2015 Permalink | Reply
    Tags: , , Lagrange points, space.com   

    From SPACE.com: “Lagrange Points: Parking Places in Space” 

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    August 19, 2015
    Elizabeth Howell

    Diagram of the Lagrange points associated with the sun-Earth system

    A Lagrange point is a location in space where the combined gravitational forces of two large bodies, such as Earth and the sun or Earth and the moon, equal the centrifugal force felt by a much smaller third body. The interaction of the forces creates a point of equilibrium where a spacecraft may be “parked” to make observations.

    These points are named after Joseph-Louis Lagrange, an 18th-century mathematician who wrote about them in a 1772 paper concerning what he called the “three-body problem.” They are also called Lagrangian points and libration points.

    Structure of Lagrange points

    There are five Lagrange points around major bodies such as a planet or a star. Three of them lie along the line connecting the two large bodies. In the Earth-sun system, for example, the first point, L1, lies between Earth and the sun at about 1 million miles from Earth. L1 gets an uninterrupted view of the sun, and is currently occupied by the Solar and Heliospheric Observatory (SOHO) and the Deep Space Climate Observatory.



    L2 also lies a million miles from Earth, but in the opposite direction of the sun. At this point, with the Earth, moon and sun behind it, a spacecraft can get a clear view of deep space. NASA’s Wilkinson Microwave Anisotropy Probe (WMAP) is currently at this spot measuring the cosmic background radiation left over from the Big Bang. The James Webb Space Telescope will move into this region in 2018.


    NASA James Webb Telescope

    The third Lagrange point, L3, lies behind the sun, opposite Earth’s orbit. For now, science has not found a use for this spot, although science fiction has.

    “NASA is unlikely to find any use for the L3 point since it remains hidden behind the sun at all times,” NASA wrote on a web page about Lagrange points. “The idea of a hidden ‘Planet-X’ at the L3 point has been a popular topic in science fiction writing. The instability of Planet X’s orbit (on a time scale of 150 years) didn’t stop Hollywood from turning out classics like ‘The Man from Planet X.’”

    L1, L2 and L3 are all unstable points with precarious equilibrium. If a spacecraft at L3 drifted toward or away from Earth, it would fall irreversibly toward the sun or Earth, “like a barely balanced cart atop a steep hill,” according to astronomer Neil DeGrasse Tyson. Spacecraft must make slight adjustments to maintain their orbits.

    Points L4 and L5, however, are stable, “like a ball in a large bowl,” according to the European Space Agency. These points lie along Earth’s orbit at 60 degrees ahead of and behind Earth, forming the apex of two equilateral triangles that have the large masses (Earth and the sun, for example) as their vertices.

    Because of the stability of these points, dust and asteroids tend to accumulate in these regions. Asteroids that surround the L4 and L5 points are called Trojans in honor of the asteroids Agamemnon, Achilles and Hector (all characters in the story of the siege of Troy) that are between Jupiter and the Sun. NASA states that there have been thousands of these types of asteroids found in our solar system, including Earth’s only known Trojan asteroid, 2010 TK7.

    Asteroid 2010 TK7 is circled in green, in this single frame taken by NASA’s Wide-field Infrared Survey Explorer, or WISE. The majority of the other dots are stars or galaxies far beyond our solar system. Astronomers discovered this object — the first known Earth Trojan asteroid — after sifting through asteroid candidates identified by WISE.
    Date October 2010
    Author NASA/Jet Propulsion Lab-Caltech/UCLA

    L4 and L5 are also possible points for a space colony due to their relative proximity to Earth, at least according to the writings of Gerard O’Neill and related thinkers. In the 1970s and 1980s, a group called the L5 Society promoted this idea among its members. In the late 1980s, it merged into a group that is now known as the National Space Society, an advocacy organization that promotes the idea of forming civilizations beyond Earth.

    If a spacecraft uses a Lagrange point close to Earth, there are many benefits to the location, the Jet Propulsion Laboratory’s Amy Mainzer told Space.com.

    Mainzer is principal investigator of NEOWISE, a mission that searches for near-Earth asteroids using the Wide-field Infrared Survey Explorer (WISE) spacecraft that orbits close to our planet. While WISE is doing well with its current three-year mission that concludes in 2016, Mainzer said, a spacecraft placed at a Lagrange point would be able to do more.

    Far from the interfering heat and light of the sun, an asteroid-hunting spacecraft at a Lagrange point would be more sensitive to the tiny infrared signals from asteroids. It could point over a wide range of directions, except very close to the sun. And it wouldn’t need coolant to stay cool, as WISE required for the first phase of its mission between 2009 and 2011 — the location itself would allow for natural cooling. The James Webb Space Telescope will take advantage of the thermal environment at the sun-Earth L2 point to help keep cool.

    L1 and L2 also “allow you to have enormous bandwidth” because over conventional Ka-band radio, the communication speeds are very high, Mainzer said. “Otherwise, the data rates just become very slow,” she said, since a spacecraft in orbit around the sun (known as heliocentric orbit) would eventually drift far from Earth.

    See the full article here.

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