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    VIRGOCosmos In Brief - Aktualní novinky vesmírného výzkumu v kostce
    VIRGO
    VIRGO --- ---
    For the 1st time since 2014 New Horizons will enter hibernation NEXT MONTH
    as it cruises to 2014 MU69. This hibernation runs 7 Apr-11 Sep.
    VIRGO
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    Catch Comet Encke this evening.
    https://www.youtube.com/watch?v=5gRdPDjL6s8
    VIRGO
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    Woow! Could we map the surface of a distant Earthlike planet by using the sun as a huge magnifying glass?

    VIRGO
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    50 000-Year-Old 'Super Life' Discovered Says Head Of NASA Astrobiology
    https://www.forbes.com/...17/02/27/50000-year-old-super-life-discovered-in-mexico-cave/#3204f85f59c1

    Deep within a Mexican cave NASA scientists discovered ancient life forms that have been trapped within crystals for 50,000 years. The cave whereby
    these microbes live is the famous Naica Cave in Mexico's Chihuahua state and is known for fairytale like massive crystals and extreme conditions.

    The microbes have been dormant within trapped fluid inclusions in massive gypsum crystals. Uniquely, the microbes have existed entirely on heavy
    minerals such as iron and manganese to create energy. They have adapted to one of the most hostile environments on Earth, evidence that life finds
    a way to cope in extreme conditions.

    To set the stage, the Naica caves were first found by miners about a hundred years ago while looking for silver. The cave system (980 feet below
    the surface of the Earth) reaches up to 136 °F and 99% humidity, conditions that require scientists to wear modified spacesuits with cooling packs
    while studying the cave. The massive gypsum crystals have grown up to 39 feet long and 13 feet in diameter, weighing up to 55 tons per crystal.

    VIRGO
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    Study opens new questions on how the atmosphere and oceans formed
    https://anu.prezly.com/study-opens-new-questions-on-how-the-atmosphere-and-oceans-formed

    A new study led by The Australian National University (ANU) has found seawater cycles throughout the Earth’s interior
    down to 2 900km, much deeper than previously thought, reopening questions about how the atmosphere and oceans formed.

    A popular theory is that the atmosphere and oceans formed by releasing water and gases from the Earth’s mantle through
    volcanic activity during the planet’s first 100 million years.

    But lead researcher Dr Mark Kendrick from ANU said the new study provided evidence to question this theory.

    “Our findings make alternative theories for the origin of the atmosphere and oceans equally plausible, such as icy
    comets or meteorites bringing water to the Earth,” said Dr Kendrick from the ANU Research School of Earth Sciences.

    Seawater is introduced into the Earth’s interior when two tectonic plates converge and one plate is pushed underneath
    the other into the mantle. The study has overturned the notion that seawater only makes it about 100km into the mantle
    before it is returned to the Earth’s surface through volcanic arcs, such as those forming the Pacific Ring of Fire that
    runs through the western America’s, Japan and Tonga.

    The team analysed samples of volcanic glass from the Atlantic, Pacific and Indian oceans that contained traces of seawater
    that had been deeply cycled throughout Earth’s interior
    VIRGO
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    Earth probably began with a solid shell | EurekAlert! Science News
    https://www.eurekalert.org/pub_releases/2017-02/uom-epb022317.php
    New research suggests that plate tectonics began later in Earth's history

    Today's Earth is a dynamic planet with an outer layer composed of giant plates that grind together, sliding past or dipping beneath one another, giving
    rise to earthquakes and volcanoes. Others separate at undersea mountain ridges, where molten rock spreads out from the centers of major ocean basins.

    But new research suggests that this was not always the case. Instead, shortly after Earth formed and began to cool, the planet's first outer layer was
    a single, solid but deformable shell. Later, this shell began to fold and crack more widely, giving rise to modern plate tectonics.

    The research, described in a paper published February 27, 2017 in the journal Nature, is the latest salvo in a long-standing debate in the geological
    research community: did plate tectonics start right away--a theory known as uniformitarianism--or did Earth first go through a long phase with a solid
    shell covering the entire planet? The new results suggest the solid shell model is closest to what really happened.

    VIRGO
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    The TRAPPIST Worlds: Should We Invest In A Backup Planet For Earth?
    https://www.forbes.com/...appist-worlds-should-we-invest-in-a-back-up-planet-for-earth/#340287386cc7
    Investing in a backup planet might be a good idea, given what’s been happening on Earth lately. The cost would only be a little over
    $20 trillion, but some nice real estate just came on the market.
    VIRGO
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    VIRGO
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    Lawrence Krauss reads from The Greatest Story Ever Told...So Far
    https://www.youtube.com/watch?v=a4tB4QbVVmE
    VIRGO
    VIRGO --- ---
    Rise of the Super Telescopes: The Overwhelmingly Large Telescope - Universe Today
    http://www.universetoday.com/...800/rise-of-the-super-telescopes-the-overwhelmingly-large-telescope/

    Adaptive Optics Discoveries
    https://www.youtube.com/watch?v=F6hmLcJOkzM
    VIRGO
    VIRGO --- ---
    Sols 1623-1624: MAHLI Diagnostics & Remote Sensing: Curiosity Mission Update by Lauren Edgar
    http://www.flickr.com/photos/105796482@N04/32321734204/sizes/l

    Today’s two-sol plan is devoted to MAHLI diagnostics and remote sensing. It’s another late slide sol, so planning started three and half hours later than usual.
    The plan kicks off with arm activities to better understand the fault that MAHLI experienced last week. Then ChemCam will investigate “Dunn Brook,” a target that
    is just above “Chase Brook” from the weekend plan, and is shown in the above Mastcam image. The target shows some interesting color variations so ChemCam will be
    used to investigate changes in composition. We’ll also acquire a ChemCam observation of “Leighton,” to study the coarse sand grains at the crest of a ripple. Then
    Navcam will look for dust devils and clouds, in response to orbital observations that suggest recent increasing atmospheric opacity. On the second sol, Mastcam
    will acquire a multispectral observation on “Dunn Brook,” and will be used to document the previous APXS locations at “Tomhegan” and “Waweig.” We’ll also acquire
    a Mastcam image for deck monitoring to assess the movement of fines, and an upper tier Navcam mosaic to enable us to target features on Mt. Sharp. The second sol
    includes a number of environmental monitoring observations, using both Mastcam and Navcam to monitor the color and opacity of the atmosphere and search for dust
    devils. The plan also includes an APXS thermal characterization test and a number of change detection observations.

    By Lauren Edgar: Lauren is a Research Geologist at the USGS Astrogeology Science Center and a member of the MSL science team.

    VIRGO
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    Bright fireball spotted over Santos, São Paulo, Brazil on February 28, 2017
    Fireball 28/02/2017 - Santos/SP
    https://www.youtube.com/watch?v=PRTRVUMoY2Y
    VIRGO
    VIRGO --- ---
    Recent Claims Invalid: Emergent Gravity Might Deliver A Universe Without Dark Matter
    https://www.forbes.com/.../02/28/is-dark-matter-about-to-be-killed-by-emergent-gravity/#2018cc775359

    Gravity is one of the four fundamental forces of nature, which means it’s not derived from anything else – it just is. At least,
    that's according to our presently accepted theories. But this may be about to change.

    Physicists today describe the gravitational interaction through Einstein’s Theory of General Relativity, which dictates the effects of gravity are due to the curvature of space-time.
    But it's already been 20 years since Ted Jacobson demonstrated that General Relativity resembles thermodynamics, which is a framework to describe how very large numbers of individual,
    constituent particles behave. Since then, physicists have tried to figure out whether this similarity is a formal coincidence or hints at a deeper truth: that space-time is made of
    small elements whose collective motion gives rise to the force we call gravity. In this case, gravity would not be a truly fundamental phenomenon, but an emergent one.

    The problem is, if emergent gravity just reproduces General Relativity, there’s no way to test the idea. What we need instead is a prediction from emergent gravity that deviates from
    General Relativity.

    Such a prediction was made two months ago by Erik Verlinde in his new paper. Verlinde pointed out that emergent gravity in a universe with a positive cosmological constant – like the
    one we live in – would only approximately reproduce General Relativity. The microscopic constituents of space-time, Verlinde claims, also react to the presence of matter in a way that
    General Relativity does not capture: they push inwards on matter. This creates an effect similar to that ascribed to particle dark matter, which pulls normal matter in by its
    gravitational attraction.

    Verlinde’s idea is interesting and solves two problems that had plagued previous attempts at emergent gravity.

    First, he conjectures that the deviations from General Relativity come about because the microscopic constituents of space-time have an additional type of entropy. In the thermodynamic
    formulation of gravity, the entropy – that is the number of possible microscopic configurations – which a volume can maximally have is proportional to the surface area of that volume.
    This is also often referred to as a “holographic” entropy because it demonstrates that all what happens inside the volume can entirely be encoded on its surface. The additional entropy
    that Verlinde introduces instead grows with the volume itself.

    The modification to General Relativity then comes about because matter – so the conjecture goes – reduces the new, volume-scaling entropy in its environment. The entropy decrease leads
    to a decrease in volume which, in turn creates a force pushing inwards on the matter. This force, Verlinde shows, is similar to the force normally attributed to dark matter – which pulls
    in normal matter from its additional gravitational mass.
    VIRGO
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    https://www.nasa.gov/feature/goddard/2017/study-hints-at-change-in-water-fingerprint-of-comet

    Astronomers from NASA’s Goddard Space Flight Center in Greenbelt, Maryland, observed the Oort cloud comet C/2014 Q2, also called Lovejoy,
    when it passed near Earth in early 2015. Through NASA’s partnership in the W. M. Keck Observatory on Mauna Kea, Hawaii, the team observed
    the comet at infrared wavelengths a few days after Lovejoy passed its perihelion – or closest point to the sun.

    VIRGO
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    Spontaneous “dust traps”: astronomers discover a missing link in planet formation
    http://www.ras.org.uk/...ntaneous-dust-traps-astronomers-discover-a-missing-link-in-planet-formation

    Planets are thought to form in the disks of dust and gas found around young stars. But astronomers have struggled to assemble
    a complete theory of their origin that explains how the initial dust develops into planetary systems. A French-UK-Australian
    team now think they have the answer, with their simulations showing the formation of 'dust traps' where pebble-sized fragments
    collect and stick together, to grow into the building blocks of planets. They publish their results in the journal Monthly
    Notices of the Royal Astronomical Society.

    VIRGO
    VIRGO --- ---
    Constraining the Chemistry of Carbon-Chain Molecules in Spacesu201708 | www.cfa.harvard.edu/
    https://www.cfa.harvard.edu/news/su201708

    The interstellar medium of the Milky Way contains 5-10% of the total mass of the galaxy (excluding its dark matter) and consists primarily of hydrogen gas. There are small
    but important contributions from other gases as well, including carbon-bearing molecules both simple, like carbon monoxide and carbon dioxide, and complex like ethene,
    benzene, propynal, methanol and other alcohols, and cyanides. There are even some very large molecules like polycyclic aromatic hydrocarbons and buckyballs with fifty or
    more carbon atoms. Some species like the cyanides have relative abundances similar to what is seen in comets in our Solar System, suggesting that local carbon chemistry
    is not unique.

    Astronomers think complex interstellar molecules are probably produced on dust grains, although some molecules might be produced in the gas phase. About one percent by mass
    of the interstellar material, these tiny grains are composed predominantly of silicates and provide the gas molecules with surfaces on which to react with other molecules.
    Carbon chain molecules are particularly interesting because they are thought to be the starting point for a significant fraction of the known complex chemicals in
    the interstellar medium. It is even suspected that carbon-chain species are a key stage in the formation of polycyclic aromatic hydrocarbons. Carbon-chain molecular
    chemistry thus provides insight into a large subset of interstellar chemistry.

    VIRGO
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    A remarkable galactic hybrid | ESA/Hubble
    https://www.spacetelescope.org/images/potw1709a/

    This NASA/ESA Hubble Space Telescope image showcases the remarkable galaxy UGC 12591. Classified as an S0/Sa galaxy, UGC 12591 sits somewhere
    between a lenticular and a spiral. It lies just under 400 million light-years away from us in the westernmost region of the Pisces–Perseus
    Supercluster, a long chain of galaxy clusters that stretches out for hundreds of light-years — one of the largest known structures in the cosmos.

    VIRGO
    VIRGO --- ---
    A New Binary Star Asteroid Belt Teaches Us About How Planets Form
    https://www.forbes.com/...-binary-star-asteroid-belt-teaches-us-about-how-planets-form/#6e9615d64d6d

    The system is called SDSS 1557. It consists of a white dwarf about the mass of our Sun, orbited by a large brown dwarf
    about 60 times more massive than Jupiter. Recently astronomers have observed a rocky asteroid belt surrounding the system.

    VIRGO
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    VIRGO
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    Science checkout continues for ExoMars orbiter / ExoMars / Space Science / Our Activities / ESA
    http://www.esa.int/...ctivities/Space_Science/ExoMars/Science_checkout_continues_for_ExoMars_orbiter

    Next week, the ExoMars orbiter will devote two days to making important calibration measurements
    at the Red Planet, which are needed for the science phase of the mission that will begin next year.

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