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  • richardmitnick 8:09 pm on December 21, 2014 Permalink | Reply
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    From Jodrell Bank: “Giant radio loops: What are they?” 

    Jodrell Bank Lovell Telescope
    Lovell

    Jodrell Bank Centre for Astrophysics

    07 Nov 2014
    Katie Brewin and Aeron Howarth
    Media Relations Officer
    The University of Manchester
    Tel: 0161 275 8387
    Email: katie.brewin@manchester.ac.uk or aeron.howarth@manchester.ac.uk

    The radio sky is full of giant loops and elongated features which have been known since the earliest days of radio astronomy. Using data from the WMAP satellite and reprocessed classic maps of the sky, a team of astronomers at Jodrell Bank suggest these loops may be produced by a nearby expanding shell driven by supernova explosions and the radiation from massive stars.

    NASA WMAP
    NASA WMAP satellite
    NASA/WMAP

    The study of the diffuse Galactic radio emission is nearly as old as radio-astronomy. The first extraterrestrial radio signal detected by Karl [Guth] Jansky in the early 1930s originated from the central region of our Galaxy.

    Later, in the 1950s, maps covering much of the sky were made which showed large elongated features and loops. Various different hypotheses for the origin of these structures are still being discussed today. The emission from the loops is produced by synchrotron radiation, where highly energetic electrons travel spiralling around magnetic field lines at almost the speed of light.

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    The famous 408 MHz map of the radio sky published by Haslam et al (1982). This version has been reprocessed by Remazeilles et al (2014).

    In 1982, Glyn Haslam and colleagues presented a full sky map at a radio frequency of 408 MHz. The map had taken more than a decade to produce and combined data from the Jodrell Bank, Effelsberg and Parkes radio telescopes. This is the most widely used synchrotron template of the sky. In this map, four Loops are visible but they are difficult to isolate from a smooth diffuse component.

    Max Planck Effelberg Radio telescope
    Effelsberg Readio Telescope

    CSIRO Parkes Observatory
    CSIRO/Parks

    Now, using data available from the WMAP satellite, we can see for the first time how the polarised radio sky looks at high radio frequencies (~30 GHz). Surprisingly, the sky is covered by a number of bright filaments, without the uniform smooth background which dominates the radio continuum maps.

    We have catalogued these new filaments and tested a model to explain the origin of some of these features. We believe that they might be caused by the interaction between an expanding shell in the solar vicinity with the magnetic field of the Galaxy. The expanding shell, powered by supernova events and the radiation from massive stars compresses the magnetic field around it, increasing the synchrotron emission from the shell. This simple model reproduces well the data in most of the areas studied.

    See the full article here.

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    Jodrell Bank Centre for Astrophysics comprises research activities in astronomy and astrophysics at The University of Manchester, the world leading facilities of the Jodrell Bank Observatory, the e-MERLIN/VLBI National Facility and the Project Development Office of the Square Kilometre Array.

    Jodrell Bank e-Merlin

    SKA Square Kilometer Array

     
  • richardmitnick 5:30 pm on December 21, 2014 Permalink | Reply
    Tags: Artificial Interlligence,   

    From livescience- “Stephen Hawking: Artificial Intelligence Could End Human Race” 

    Livescience

    December 02, 2014
    Tanya Lewis

    The eminent British physicist Stephen Hawking warns that the development of intelligent machines could pose a major threat to humanity.

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    Stephen Hawking recently began using a speech synthesizer system that uses artificial intelligence to predict words he might use.
    Credit: Flickr/NASA HQ PHOTO.

    “The development of full artificial intelligence (AI) could spell the end of the human race,” Hawking told the BBC.

    The famed scientist’s warnings about AI came in response to a question about his new voice system. Hawking has a form of the progressive neurological disease called amyotrophic lateral sclerosis (ALS or Lou Gehrig’s disease), and uses a voice synthesizer to communicate. Recently, he has been using a new system that employs artificial intelligence. Developed in part by the British company Swiftkey, the new system learns how Hawking thinks and suggests words he might want to use next, according to the BBC.

    Humanity’s biggest threat?

    Fears about developing intelligent machines go back centuries. More recent pop culture is rife with depictions of machines taking over, from the computer HAL in Stanley Kubrick’s 2001: A Space Odyssey to Arnold Schwarzenegger’s character in The Terminator films.

    Inventor and futurist Ray Kurzweil, director of engineering at Google, refers to the point in time when machine intelligence surpasses human intelligence as “the singularity,” which he predicts could come as early as 2045. Other experts say such a day is a long way off.

    It’s not the first time Hawking has warned about the potential dangers of artificial intelligence. In April, Hawking penned an op-ed for The Huffington Post with well-known physicists Max Tegmark and Frank Wilczek of MIT, and computer scientist Stuart Russell of the University of California, Berkeley, forecasting that the creation of AI will be “the biggest event in human history.” Unfortunately, it may also be the last, the scientists wrote.

    And they’re not alone — billionaire entrepreneur Elon Musk called artificial intelligence “our biggest existential threat.” The CEO of the spaceflight company SpaceX and the electric car company Tesla Motors told an audience at MIT that humanity needs to be “very careful” with AI, and he called for national and international oversight of the field.

    It wasn’t the first time Musk warned about AI’s dangers. In August, he tweeted, “We need to be super careful with AI. Potentially more dangerous than nukes.” In March, Musk, Facebook founder Mark Zuckerberg and actor Ashton Kutcher jointly invested $40 million in an AI company that is working to create an artificial brain.

    Overblown fears

    But other experts disagree that AI will spell doom for humanity. Charlie Ortiz, head of AI at the Burlington, Massachusetts-based software company Nuance Communications, said the concerns are “way overblown.”

    “I don’t see any reason to think that as machines become more intelligent … which is not going to happen tomorrow — they would want to destroy us or do harm,” Ortiz told Live Science.

    Fears about AI are based on the premise that as species become more intelligent, they have a tendency to be more controlling and more violent, Ortiz said. “I’d like to think the opposite. As we become more intelligent, as a race we become kinder and more peaceful and treat people better,” he said.

    Ortiz said the development of super-intelligent machines is still an important issue, but he doesn’t think it’s going to happen in the near future. “Lots of work needs to be done before computers are anywhere near that level,” he said.

    See the full article here.

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  • richardmitnick 6:43 am on December 21, 2014 Permalink | Reply
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    From astrobio.net: “Asteroid that wiped out dinosaurs may have nearly knocked off mammals, too” 

    Astrobiology Magazine

    Astrobiology Magazine

    Dec 20, 2014
    Source: Pensoft Publishers

    The extinction of the dinosaurs 66 million years ago is thought to have paved the way for mammals to dominate, but a new study shows that many mammals died off alongside the dinosaurs.

    Metatherian mammals–the extinct relatives of living marsupials (“mammals with pouches”, such as opossums) thrived in the shadow of the dinosaurs during the Cretaceous period. The new study, by an international team of experts on mammal evolution and mass extinctions, shows that these once-abundant mammals nearly followed the dinosaurs into oblivion.

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    Part of skeleton of Lycopsis longirostris, a fossil marsupial
    Lycopsis is an extinct genus of South American metatherian, that lived during the Miocene.

    When a 10-km-wide asteroid struck what is now Mexico at the end of the Cretaceous and unleashed a global cataclysm of environmental destruction, some two-thirds of all metatherians living in North America perished. This includes more than 90% of species living in the northern Great Plains of the USA, the best area in the world for preserving latest Cretaceous mammal fossils.

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    This diagram is showing how severely metatherian mammals were affected when an asteroid hit Earth at the end of the Cretaceous, 66 million years ago. In North America, the number of metatherian species dropped from twenty species within the last million years of the Cretaceous Period, to just three species in the first million years of the Paleogene Period. Credit: Dr Thomas Williamson

    In the aftermath of the mass extinction, metatherians would never recover their previous diversity, which is why marsupial mammals are rare today and largely restricted to unusual environments in Australia and South America.

    Taking advantage of the metatherian demise were the placental mammals: species that give live birth to well-developed young. They are ubiquitous across the globe today and include everything from mice to men.

    Dr. Thomas Williamson of the New Mexico Museum of Natural History and Science, lead author on the study, said: “This is a new twist on a classic story. It wasn’t only that dinosaurs died out, providing an opportunity for mammals to reign, but that many types of mammals, such as most metatherians, died out too – this allowed advanced placental mammals to rise to dominance.”

    Dr. Steve Brusatte of the University of Edinburgh‘s School of GeoSciences, an author on the report, said: “The classic tale is that dinosaurs died out and mammals, which had been waiting in the wings for over 100 million years, then finally had their chance. But our study shows that many mammals came perilously close to extinction. If a few lucky species didn’t make it through, then mammals may have gone the way of the dinosaurs and we wouldn’t be here.”

    Dr. Gregory Wilson of the University of Washington also took part in the study.

    The new study is published in the open access journal ZooKeys. It reviews the Cretaceous evolutionary history of metatherians and provides the most up-to-date family tree for these mammals based on the latest fossil records, which allowed researchers to study extinction patterns in unprecedented detail.

    See the full article here.

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    NASA

     
  • richardmitnick 6:13 am on December 21, 2014 Permalink | Reply
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    From Seth Shostak at SETI: “Mars Methane: Life at Last?” 


    SETI Institute

    Dec 20, 2014

    SETI Seth Shostak
    Dr. Seth Shostak, Senior Astronomer and Director of SETI Research

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    Mars is a tease.

    It seems that discoveries hinting at life on the Red Planet are as recurrent as Kansas hay fever. Open up the science section of any periodical, and you’ll invariably trip across new research encouraging us to believe that somewhere, skulking in the vast, dry landscapes of that desolate world, are small, wiggling creatures — fellow inhabitants of the solar system.

    Such enticing tidbits are nothing new. Their modern incarnation dates back to the early 1900s, when astronomer Percival Lowell promoted the existence of Martians who had trussed their planet with irrigation canals. This idea was well received by the public, but the astronomical community was at first skeptical, and eventually dismissive. By the First World War, these sluice-happy Martians were vaporware.

    As the century ground on, additional see-saw arguments for martian life made regular appearances. In the 1970s, the Viking Landers, with the best science instrumentation NASA could launch, went looking for life in the martian dirt. The verdict was that they didn’t find any. But one member of the Viking biology team doesn’t agree. Was it a hit or a whiff? We still can’t say for sure.

    NASA Viking
    NASA/Viking

    Then in 1996, claims of fossilized microbes in a meteorite known to come from Mars became the biggest science news story of the year. But were the seductive squiggles seen under the microscope really dead Red Planet microbes, or were they just inanimate features that mimicked croaked critters? Again, the jury has not returned to the court room.

    This litany of teases continues today with the saga of martian methane.

    Methane is best known on Earth as natural gas, and there’s a good chance it’s powering the device you’re using to read this. It’s the simplest of the organic molecules. “Organic,” by the way, doesn’t mean that it’s necessarily the product of biology, or that it was grown on a farm that shuns pesticides. It just means that the molecule incorporates carbon as one of its constituent elements. Since carbon has four covalent bonds, the simplest molecule you can make with this stuff is by attaching a hydrogen atom to each of these “chemical arms.” CH4 is the result, known to savvy 11th graders as methane.

    But in the context of extraterrestrial life, methane is important as a possible biomarker. It’s the exhaust gas of many forms of life on Earth — bacteria, most notably, but also slightly bulkier organisms such as cattle and pigs. If you detect methane in a planet’s atmosphere, you may have found pigs in space. Or more likely, microbes in space.

    In 2004, the Europeans launched the Mars Express orbiter, and did just that. They claimed that their spacecraft had spectroscopically sniffed clouds of methane wafting above the Red Planet. American astronomers, using ground-based telescopes, also thought they had sensed this gas. The claim was important, if true, because CH4 could be caused by underground, martian bacteria. If so, this would be the first detection of life beyond Earth.

    ESA Mars Express OrbiterESA Mars Express schematic
    ESA/Mars Express

    And even more, it would be living life. Not the dead microbes supposedly entombed in a meteorite, but metabolizing Martians that were still kicking. That’s because ultraviolet light from the Sun, untroubled by an ozone layer that Mars doesn’t have, would take apart any methane molecules in the atmosphere within 300 years or so. So if there’s methane around, it’s today’s methane (note to reader: for astronomers, 300 years ago is the same as “today”).

    Given this back story, you can imagine the considerable interest when NASA’s Curiosity rover bounced onto the sands of our little ruddy buddy in 2012, equipped with instruments that could also check for methane. The result, announced in September 2013, was that it couldn’t find any at a level under a part per billion, or roughly ten times lower than expected on the basis of the earlier measurements. You might guess that maybe Curiosity had the bad luck to land in a spot far from the madding, methane cloud. Sure, but scientists figure that — thanks to the circulation of its thin atmosphere — any gas spewed out in one spot would get spread around the entire planet within months. You should be able to detect it anywhere, if there’s enough of it.

    NASA Mars Curiosity Rover
    Curiosity

    The 2013 negative result from Curiosity was, indeed, both curious and a downer. But this week, researchers attending a conference of the American Geophysical Union in San Francisco heard of the detection of a sudden spike in methane. In a truly remarkable measurement by Curiosity, we find that the gas is back.

    That’s exciting news, but history cautions us not to party hearty just yet. Methane can be produced by geophysics as well as biology, when rocks and water interact chemically. Just because it smells like a duck, doesn’t mean it’s a duck.

    So what gives? No one’s sure yet; the obvious variability in the presence of methane suggests local sources, but the big question is whether the source is geophysical or biological.

    Nathalie Cabrol, a SETI Institute astrobiologist who is especially interested in the habitability of Mars, said, “The good news is that we now know sources of methane exist. This is something that we’ve measured.”

    Cabrol is cautious about concluding that these latest discoveries are even semi-solid evidence for biology, but there’s little doubt that such a scenario is possible.

    “There may not be an easy way to untangle whether the source of the gas is geophysical or biological,” Cabrol notes. “But if life evolved on Mars and survived eons of sudden and drastic climate changes, it might have evolved strategies analogous to dormant species on Earth. Bacteria can survive millions of years in terrestrial permafrost, awaiting the return of favorable conditions to start up their metabolism and multiply.”

    It might be life, or it might not be. But the good news is that we now have evidence of some sort of activity under the surface of Mars — phenomena subject to solid, repeatable measurement.

    Long everyone’s favorite place to search for extraterrestrial life, the Red Planet continues to taunt us a century after Percival Lowell assured us that it was both inhabited and cultivated. At least the first is still possible.

    See the full article here.

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    Mountain View, CA 94043
    Phone 650.961.6633 – Fax 650-961-7099
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  • richardmitnick 5:49 am on December 21, 2014 Permalink | Reply
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    From SPACE.com: “How Was the Moon Formed?” 2013 

    space-dot-com logo

    SPACE.com

    After the sun spun to light, the planets of the solar system began to form. But it took another hundred million years for Earth’s moon to spring into existence. There are three theories as to how our planet’s satellite could have been created: the giant impact hypothesis, the co-formation theory and the capture theory.

    Giant impact hypothesis

    This is the prevailing theory supported by the scientific community. Like the other planets, the Earth formed from the leftover cloud of dust and gas orbiting the young sun. The early solar system was a violent place, and a number of bodies were created that never made it to full planetary status. According to the giant impact hypothesis, one of these crashed into Earth not long after the young planet was created.

    Known as Theia, the Mars-size body collided with Earth, throwing vaporized chunks of the young planet’s crust into space. Gravity bound the ejected particles together, creating a moon that is the largest in the solar system in relation to its host planet. This sort of formation would explain why the moon is made up predominantly of lighter elements, making it less dense than Earth — the material that formed it came from the crust, while leaving the planet’s rocky core untouched. As the material drew together around what was left of Theia’s core, it would have centered near Earth’s ecliptic plane, the path the sun travels through the sky, which is where the moon orbits today.

    Co-formation theory

    Moons can also form at the same time as their parent planet. Under such an explanation, gravity would have caused material in the early solar system to draw together at the same time as gravity bound particles together to form Earth. Such a moon would have a very similar composition to the planet, and would explain the moon’s present location. However, although Earth and the moon share much of the same material, the moon is much less dense than our planet, which would likely not be the case if both started with the same heavy elements at their core.

    Capture theory

    Perhaps Earth’s gravity snagged a passing body, as happened with other moons in the solar system, such as the Martian moons of Phobos and Deimos. Under the capture theory, a rocky body formed elsewhere in the solar system could have been drawn into orbit around the Earth. The capture theory would explain the differences in the composition of the Earth and its moon. However, such orbiters are often oddly shaped, rather than being spherical bodies like the moon. Their paths don’t tend to line up with the ecliptic of their parent planet, also unlike the moon.

    Although the co-formation theory and the capture theory both explain some elements of the existence of the moon, they leave many questions unanswered. At present, the giant impact hypothesis seems to cover many of these questions, making it the best model to fit the scientific evidence for how the moon was created.
    Conceptual illustrations of the birth of the moon.

    m1

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    m3

    m4

    m5

    m6

    See the full article, with video, here.

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  • richardmitnick 6:04 pm on December 20, 2014 Permalink | Reply
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    From SPACE.com: “Orion’s Belt: String of Stars & Region of Star Birth” 

    space-dot-com logo

    SPACE.com

    December 20, 2014
    Elizabeth Howell

    Orion’s Belt is an asterism of three stars that appear about midway in the constellation Orion the Hunter. The asterism is so called because it appears to form a belt in the hunter’s outfit. It is one of the most famous asterisms used by amateur astronomers. Asterisms are patterns of stars of similar brightness. The stars may be part of a larger constellation or may be formed from stars in different constellations.

    Spotting the belt is actually one of the easiest ways to find the constellation Orion itself, which is among the brightest and most prominent in the winter sky. The three stars that traditionally make up the belt are, from west to east: Mintaka, Alnilam and Alnitak. The names of the outer two both mean “belt” in Arabic, while Alnilam comes from an Arabis word that mean “string of pearls,” which is the name of the whole asterism in Arabic, according to astronomer Jim Kaler.

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    The stars Alnilam, Mintaka and Alnitak form Orion’s belt.
    Credit: Martin Mutti, Astronomical Image Data Archive

    Hanging down from Orion’s Belt is his sword, which is made up of three fainter stars. The central “star” of the sword is actually the Orion Nebula (M42), a famous region of star birth. The Horsehead Nebula (IC 434), which is a swirl of dark dust in front of a bright nebula, is also nearby.

    o
    In one of the most detailed astronomical images ever produced, NASA/ESA’s Hubble Space Telescope captured an unprecedented look at the Orion Nebula. … This extensive study took 105 Hubble orbits to complete. All imaging instruments aboard the telescope were used simultaneously to study Orion. The Advanced Camera mosaic covers approximately the apparent angular size of the full moon.

    NASA Hubble Telescope
    NASA Hubble schematic
    Hubble

    Looking north of the belt, Orion’s “shoulders” are marked by Betelgeuse and Bellatrix and south, his “knees” are Saiph and Rigel.

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    Skywatcher Per-Magnus Heden wondered if the Vikings gazed at the same starry sky, which includes the constellation Orion at bottom, when he took this photo in Feb. 2011.
    Credit: P-M Hedén/TWAN

    Cultural references and notable features

    “The only real legend that is sometimes referred to in Western Culture with Orion’s Belt is the Three Kings,” said Tom Kerss, an astronomer with the Royal Observatory Greenwich, in a Space.com interview. This is a direct reference to the Biblical tale of the three kings who offered gifts to the Baby Christ shortly after his birth.

    Because Orion’s Belt is so easy to find in the sky, it can be used as a pointer to bring amateur astronomers to other interesting objects. Move northwest of the star complex and eventually the line will bring you to the Pleiades star cluster, a collection of dozens of stars that are sometimes called the Seven Sisters (after those that are the most easily visible to the naked eye.)

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    The Pleiades, an open cluster consisting of approximately 3,000 stars at a distance of 400 light-years (120 parsecs) from Earth in the constellation of Taurus. It is also known as “The Seven Sisters”, or the astronomical designations NGC 1432/35 and M45.

    http://hubblesite.org/newscenter/archive/releases/2004/20/image/a/

    Following southwest of the stars will lead you to Sirius, the brightest star in the sky in both the Northern and Southern hemispheres. Part of its brightness in the sky comes because it is so close to us, just 8.7 light-years away.

    Kerss said the shape is also interesting astronomically. Some of the stars themselves are physically close together (which is not always true of stars in the sky, which only appear to be nearby.)
    Recent astronomical news

    Although the Orion Nebula has been studied thoroughly by both amateur and professional astronomers, surprises continue with further observations.

    In 2013, a Chilean European Southern Observatory telescope spotted signs of a cosmic “ribbon” in the nebula that is more than 1,000 light-years away. The track contains cold gas and dust, and astronomers also noted they may have found 15 young stars or protostars while making these observations.

    Even closer looks at the nebula have revealed features such as this bow shock from the young star LL Ori, which is sending out wind that strikes gas leaving the heart of the star-forming region.

    See the full article here.

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  • richardmitnick 8:45 am on December 20, 2014 Permalink | Reply
    Tags: , , University of Leeds,   

    From Leeds: “Scientists observe the Earth grow a new layer under an Icelandic volcano” 

    Leeds

    University of Leeds

    15 December 2014
    No Writer Credit

    New research into an Icelandic eruption has shed light on how the Earth’s crust forms, according to a paper published today in Nature.

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    When the Bárðarbunga volcano, which is buried beneath Iceland’s Vatnajökull ice cap, reawakened in August 2014, scientists had a rare opportunity to monitor how the magma flowed through cracks in the rock away from the volcano.

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    The molten rock forms vertical sheet-like features known as dykes, which force the surrounding rock apart.

    Study co-author Professor Andy Hooper from the Centre for Observation and Modelling of Earthquakes, volcanoes and Tectonics (COMET) at the University of Leeds explained: “New crust forms where two tectonic plates are moving away from each other. Mostly this happens beneath the oceans, where it is difficult to observe.

    “However, in Iceland this happens beneath dry land. The events leading to the eruption in August 2014 are the first time that such a rifting episode has occurred there and been observed with modern tools, like GPS and satellite radar.”

    Although it has a long history of eruptions, Bárðarbunga has been increasingly restless since 2005. There was a particularly dynamic period in August and September this year, when more than 22,000 earthquakes were recorded in or around the volcano in just four weeks, due to stress being released as magma forced its way through the rock.

    Using GPS and satellite measurements, the team were able to track the path of the magma for over 45km before it reached a point where it began to erupt, and continues to do so to this day. The rate of dyke propagation was variable and slowed as the magma reached natural barriers, which were overcome by the build-up of pressure, creating a new segment.

    The dyke grows in segments, breaking through from one to the next by the build up of pressure. This explains how focused upwelling of magma under central volcanoes is effectively redistributed over large distances to create new upper crust at divergent plate boundaries, the authors conclude.

    As well as the dyke, the team found ‘ice cauldrons’ – shallow depressions in the ice with circular crevasses, where the base of the glacier had been melted by magma. In addition, radar measurements showed that the ice inside Bárðarbunga’s crater had sunk by 16m, as the volcano floor collapsed.

    COMET PhD student Karsten Spaans from the University of Leeds, a co-author of the study, added: “Using radar measurements from space, we can form an image of caldera movement occurring in one day. Usually we expect to see just noise in the image, but we were amazed to see up to 55cm of subsidence.”

    Like other liquids, magma flows along the path of least resistance, which explains why the dyke at Bárðarbunga changed direction as it progressed. Magma flow was influenced mostly by the lie of the land to start with, but as it moved away from the steeper slopes, the influence of plate movements became more important.

    Summarising the findings, Professor Hooper said: “Our observations of this event showed that the magma injected into the crust took an incredibly roundabout path and proceeded in fits and starts.

    “Initially we were surprised at this complexity, but it turns out we can explain all the twists and turns with a relatively simple model, which considers just the pressure of rock and ice above, and the pull exerted by the plates moving apart.

    The paper Segmented lateral dyke growth in a rifting event at Bárðarbunga volcanic system, Iceland is published in Nature on 15 December 2014.

    The research leading to these results has received funding from the European Community’s Seventh Framework Programme under Grant Agreement No. 308377 (Project FUTUREVOLC).

    Read the paper here: http://www.nature.com/nature/journal/vaop/ncurrent/full/nature14111.html

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    The University of Leeds was founded in 1904, but its origins go back to t­he nineteenth century with the founding of the Leeds School of Medicine in 1831 and then the Yorkshire College of Science in 1874.

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  • richardmitnick 6:35 am on December 20, 2014 Permalink | Reply
    Tags: , , Ohio State University   

    From OSU: “Study Hints that Ancient Earth Made Its Own Water—Geologically” 

    OSU

    Ohio State University

    December 17, 2014
    Pam Frost Gorder

    A new study is helping to answer a longstanding question that has recently moved to the forefront of earth science: Did our planet make its own water through geologic processes, or did water come to us via icy comets from the far reaches of the solar system?

    The answer is likely “both,” according to researchers at The Ohio State University— and the same amount of water that currently fills the Pacific Ocean could be buried deep inside the planet right now.

    At the American Geophysical Union (AGU) meeting on Wednesday, Dec. 17, they report the discovery of a previously unknown geochemical pathway by which the Earth can sequester water in its interior for billions of years and still release small amounts to the surface via plate tectonics, feeding our oceans from within.

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    Wendy Panero

    In trying to understand the formation of the early Earth, some researchers have suggested that the planet was dry and inhospitable to life until icy comets pelted the earth and deposited water on the surface.

    Wendy Panero, associate professor of earth sciences at Ohio State, and doctoral student Jeff Pigott are pursuing a different hypothesis: that Earth was formed with entire oceans of water in its interior, and has been continuously supplying water to the surface via plate tectonics ever since.

    Researchers have long accepted that the mantle contains some water, but how much water is a mystery. And, if some geological mechanism has been supplying water to the surface all this time, wouldn’t the mantle have run out of water by now?

    Because there’s no way to directly study deep mantle rocks, Panero and Pigott are probing the question with high-pressure physics experiments and computer calculations.

    “When we look into the origins of water on Earth, what we’re really asking is, why are we so different than all the other planets?” Panero said. “In this solar system, Earth is unique because we have liquid water on the surface. We’re also the only planet with active plate tectonics. Maybe this water in the mantle is key to plate tectonics, and that’s part of what makes Earth habitable.”

    Central to the study is the idea that rocks that appear dry to the human eye can actually contain water—in the form of hydrogen atoms trapped inside natural voids and crystal defects. Oxygen is plentiful in minerals, so when a mineral contains some hydrogen, certain chemical reactions can free the hydrogen to bond with the oxygen and make water.

    Stray atoms of hydrogen could make up only a tiny fraction of mantle rock, the researchers explained. Given that the mantle is more than 80 percent of the planet’s total volume, however, those stray atoms add up to a lot of potential water.

    In a lab at Ohio State, the researchers compress different minerals that are common to the mantle and subject them to high pressures and temperatures using a diamond anvil cell—a device that squeezes a tiny sample of material between two diamonds and heats it with a laser—to simulate conditions in the deep Earth. They examine how the minerals’ crystal structures change as they are compressed, and use that information to gauge the minerals’ relative capacities for storing hydrogen. Then, they extend their experimental results using computer calculations to uncover the geochemical processes that would enable these minerals to rise through the mantle to the surface—a necessary condition for water to escape into the oceans.

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    This plate tectonics diagram from the Byrd Polar and Climate Research Center shows how mantle circulation delivers new rock to the crust via mid-ocean ridges. New research suggests that mantle circulation also delivers water to the oceans.

    In a paper now submitted to a peer-reviewed academic journal, they reported their recent tests of the mineral bridgmanite, a high-pressure form of olivine. While bridgmanite is the most abundant mineral in the lower mantle, they found that it contains too little hydrogen to play an important role in Earth’s water supply.

    Another research group recently found that ringwoodite, another form of olivine, does contain enough hydrogen to make it a good candidate for deep-earth water storage. So Panero and Pigott focused their study on the depth where ringwoodite is found—a place 325-500 miles below the surface that researchers call the “transition zone”—as the most likely region that can hold a planet’s worth of water. From there, the same convection of mantle rock that produces plate tectonics could carry the water to the surface.

    One problem: If all the water in ringwoodite is continually drained to the surface via plate tectonics, how could the planet hold any in reserve?

    For the research presented at AGU, Panero and Pigott performed new computer calculations of the geochemistry in the lowest portion of the mantle, some 500 miles deep and more. There, another mineral, garnet, emerged as a likely water-carrier—a go-between that could deliver some of the water from ringwoodite down into the otherwise dry lower mantle.

    If this scenario is accurate, the Earth may today hold half as much water in its depths as is currently flowing in oceans on the surface, Panero said—an amount that would approximately equal the volume of the Pacific Ocean. This water is continuously cycled through the transition zone as a result of plate tectonics.

    “One way to look at this research is that we’re putting constraints on the amount of water that could be down there,” Pigott added.

    Panero called the complex relationship between plate tectonics and surface water “one of the great mysteries in the geosciences.” But this new study supports researchers’ growing suspicion that mantle convection somehow regulates the amount of water in the oceans. It also vastly expands the timeline for Earth’s water cycle.

    “If all of the Earth’s water is on the surface, that gives us one interpretation of the water cycle, where we can think of water cycling from oceans into the atmosphere and into the groundwater over millions of years,” she said. “But if mantle circulation is also part of the water cycle, the total cycle time for our planet’s water has to be billions of years.”

    See the full article here.

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  • richardmitnick 6:09 am on December 20, 2014 Permalink | Reply
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    From RAS: “Science and Innovation Strategy: RAS Response” 

    Royal Astronomical Society

    Royal Astronomical Society

    Friday, 19 December 2014
    No Writer Credit

    The UK government published its new Science and Innovation strategy on Wednesday 17 December. The new document, “Our Plan for Growth: science and innovation” includes a number of positive announcements and restatements of support for projects in astronomy and geophysics, such as the capital funding for the Square Kilometre Array (SKA) radio observatory and the Polar Research Ship, and the more recent support for the European Space Agency to develop the ExoMars mission.

    SKA Pathfinder Radio Telescope
    SKA Pathfinder telescope

    ESA ExoMars
    ESA/ExoMars

    The Society welcomes these, along with the statement of support for peer review in investment decisions; the importance of international collaboration, the new targets for the recruitment of maths and physics teachers, the new postgraduate loans scheme, the recognition of the success of the Gaia and Rosetta missions and the opportunities presented by Major Tim Peake’s flight to the International Space Station next year.

    ESA Gaia satellite
    ESA/Gaia

    ESA Rosetta spacecraft
    ESA/Rosetta

    More generally, one of the long-standing concerns of the scientific community has been the low level of public (and private) funding for science compared with other EU and OECD countries. The new strategy explicitly addresses this, with a pledge to examine resource spending in the 2015 Spending Review. The Society welcomes this commitment and the overarching statement that policies for science and innovation should not detract from the importance of fundamental research being carried out for its own sake.

    International collaboration, including UK leadership in European scientific programmes such as Horizon 2020, also has a high prominence. The Society endorses this view and the pledge to use the UK presidency of the EU to support this activity.

    The RAS however remains concerned about several fundamental areas, including the lack of commitment to protect the science ‘ring fence’. This flat cash budget has already been eroded significantly since 2010 and even a low inflation environment will have a serious impact on purchasing power in the years ahead. If this policy continues, the inevitable outcome will be a reduction in the resources (not least postgraduate students and postdoctoral researchers) needed to exploit scientific data. This could greatly hinder the UK’s ability to reap the full benefits of the capital investment in scientific projects. And although there is recognition of the need to recruit the most talented people from across the globe, though there seems no prospect of a loosening of the restrictions on immigration that can make such recruitment almost impossible in practice.

    President of the Royal Astronomical Society Prof Martin Barstow commented: “I am delighted to see that the Government so clearly recognises the importance of scientific research, including the ‘blue skies’ sciences that are so important to the RAS and our Fellows and which are so valued by the wider public. There has though been a hollowing out of the resource budget needed to make the most of our involvement and investment in major scientific programmes, something that will need to be tackled if the UK is to remain a world player in research. As RAS President I will be pressing the Government to tackle this in next year’s Spending Review, in order to deliver the secure environment that will allow our researchers to flourish.”

    See the full article here.

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    The Royal Astronomical Society (RAS), founded in 1820, encourages and promotes the study of astronomy, solar-system science, geophysics and closely related branches of science.

     
  • richardmitnick 5:50 am on December 20, 2014 Permalink | Reply
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    From Huff Post: “New Stonehenge Discovery Hailed As ‘Most Important In 60 Years'” 

    Huffington Post
    The Huffington Post

    Archaeologists studying Stonehenge and its environs say they’ve unearthed the remnants of an untouched, ancient encampment that dates back 6,000 years–a find that could rewrite British prehistory.

    s
    Stonehenge

    “This is the most important discovery at Stonehenge in over 60 years,” Professor Tim Darvill, a Bournemouth University archaeologist and a Stonehenge expert who was not involved in the new discovery, told the Telegraph. And as he told The Huffington Post in an email, the discovery overturns previous theories that “Stonehenge was built in a landscape that was not heavily used before about 3000 B.C.”

    But if scientists are buzzing about the discovery, they’re also bummed about a new government plan calling for the construction of a new tunnel underneath Stonehenge.

    The discovery was made during a dig at Blick Mead, a site about 1.5 miles from Stonehenge. Researchers found charcoal dating back to 4,000 B.C. and evidence of “possible structures,” according to a statement released by the university. They also unearthed burnt flint and tools, as well as the remains of aurochs–ancient cattle that served as food for ancient hunter-gatherers.

    The researchers plan further analysis on the artifacts but say they’re worried the tunnel construction could damage the site and get in the way of their work.

    “Blick Mead could explain what archaeologists have been searching for for centuries–an answer to the story of Stonehenge’s past,” David Jaques, the University of Buckingham archaeologist who discovered the encampment, told The Guardian. “But our only chance to find out about the earliest chapter of Britain’s history could be wrecked if the tunnel goes ahead.”

    Stonehenge, a prehistoric monument consisting of a ring of standing stones, is located eight miles north of Salisbury, England in Wiltshire. It has been listed as a World Heritage Site since 1986.

    See the full article here.

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