• úvod
  • témata
  • události
  • tržiště
  • diskuze
  • nástěnka
  • přihlásit
    registrace
    ztracené heslo?
    VIRGOCosmos In Brief - Aktualní novinky vesmírného výzkumu v kostce




    For every complex question, there's a simple answer that's completely wrong.
    rozbalit záhlaví
    DARKMOOR
    DARKMOOR --- ---
    JULIANNE: Je to jasné, vycucli ti tu myšlenku z hlavy. Pro příště neváhat, psát a publikovat ;)
    VIRGO
    VIRGO --- ---
    JULIANNE: :-))

    Ostych stranou, tato témata jsou dnes už "na pořadu (každého) dne." :D
    JULIANNE
    JULIANNE --- ---
    Člověk má od dubna rozepsaný draft článku k teoretickým možnostem charakterizace pulsarových planet, říká si, že otázku obyvatelnosti nezmíní, aby už tak poněkud futuristické téma nepůsobilo moc šíleně, a on k tomu mezitím vznikne článek :):
    [1705.07688] Neutron Star Planets: Atmospheric processes and habitability
    https://arxiv.org/abs/1705.07688
    VIRGO
    VIRGO --- ---
    Detecting Exoplanet Life in Our Proximity | astrobites
    https://astrobites.org/2017/08/01/detecting-exoplanet-life-in-our-proximity/

    Detecting Proxima b’s Atmosphere with JWST Targeting CO2 at 15 Micron Using a High-Pass Spectral Filtering Technique.

    Since the discovery of this close planet, researchers have been studying methods that might detect the presence of life on Proxima Centauri b.
    Today’s paper by devising a method to detect CO2 in the planet’s atmosphere. They focus on this particular molecule because it is one of the
    four main biomarkers used in evaluating habitability of exoplanets; water, methane, carbon dioxide, and oxygen are primarily produced during
    biological processes, so their presence in the atmosphere implies life. In addition to being a biomarker molecule, carbon dioxide (CO2) has
    many distinguishable features that are visible on the 15 micron band, which JWST is equipped to look at.

    These researchers present a technique that can be performed with the soon-to-be-launched James Webb Space Telescope (JWST) which will reveal
    the presence of CO2 in the atmosphere of this nearby exoplanet. The emission in the 15 micron band will be ideal for detecting CO2, since
    this molecule has over 100 features within this band.

    VIRGO
    VIRGO --- ---
    Pořád probíhá vyhodnocování výsledků posledního pozorování zákrytu. Podle posledních výsledků je 2014 MU69 výrazně nesferický,
    možná dokonce kontaktní binární objekt, v extrémním případě může jít dokonce o dvojici objektů. Odhadovaná podélná velikost v případě
    jednoho asymetrického tělesa je zhruba 30 km, v případě dvojice (ať už kontaktní či těsně obíhající) 15 - 20 km pro každý objekt.

    https://www.nasa.gov/feature/new-horizons-next-target-just-got-a-lot-more-interesting

    VIRGO
    VIRGO --- ---
    VIRGO
    VIRGO --- ---
    No a report měsíce - tým DES (Dark Energy Survey) dnes oficiálně publikoval výsledky ročního výzkumu vesmíru na velkých škálách
    (i když tento program probíhá už 4 roky), pomocí 4m teleskopu observatoře Cerro Tololo na speciálně vytvořené 570 Mpx kameře DECam,
    vyvinuté ve Fermilabu. Její citlivost umožňuje zachytit světlo galaxií vzdálených 8 mld svět. let od nás (což odpovídá zhruba 1/3
    staří současného vesmíru).

    Snímkováno a zaneseno do mapy bylo na 26 000 000 galaxií, jedním z hlavních cílů programu bylo podrobné pozorování temné hmoty a energie,
    které tvoří 96 % obsahu pozorovaného vesmíru. Studie potvrdila sočasný konsenzus rozložení: viditelná 4%, TH 26%, TE 70% (zaokrouhleno).

    Výsledkem je dosud nejpodrobnější mapa navelkých škálách, co víc výsledky jsou v dobré shodě s měřením detektorem PLANCK.

    http://news.fnal.gov/...k-energy-survey-reveals-accurate-measurement-dark-matter-structure-universe/



    Hlavní rozcestník/seznam článků, které budou cca do týdne publikovány na arXivu:
    https://www.darkenergysurvey.org/des-year-1-cosmology-results-papers/

    Živé záznamy: http://vms.fnal.gov/asset/livevideo

    SLAC and Stanford astrophysicists made crucial contributions to the galaxy survey,
    showing that the universe clumps and expands as predicted by our best cosmological models.

    https://www6.slac.stanford.edu/...odel-universe-withstands-most-precise-test-dark-energy-survey.aspx

    https://www.youtube.com/watch?v=kts4PxFwUSo

    Dark Energy Survey Year 1 Results: Galaxy-Galaxy Lensing
    http://www.darkenergysurvey.org/wp-content/uploads/2017/08/y1ggl.pdf



    The paper describing the redshift distributions for the 26 million weak lensing source galaxies.
    http://www.darkenergysurvey.org/wp-content/uploads/2017/08/y1kpdndz.pdf



    Dark energy is so weak you'd need a cube of it 160km across to boil a kettle - @joezuntz

    VIRGO
    VIRGO --- ---
    Strict rules around contamination hamper exploration for life | Cosmos
    https://cosmosmagazine.com/...ct-rules-around-contamination-hamper-exploration-for-life-beyond-earth

    Is our search for alien life being held back by our desire to protect it?

    NASA’s orbiter Cassini will make a series of decreasing orbits that will end in a fiery death dive into Saturn’s atmosphere in
    September. This deliberate termination of a still serviceable spacecraft is to comply with “planetary protection” protocols,
    designed to minimise the risk of depositing stowaway Earth microbes into an environment where they might be able to reproduce.

    The particular fear in this case is that if Cassini were allowed to become derelict in orbit it might eventually crash into Enceladus –
    a moon of Saturn now realised to have a watery interior that is eminently habitable for microbes. By similar reasoning, NASA’s first
    Jupiter orbiter Galileo was made to burn up in the planet’s atmosphere in 2003 rather than risk a future crash into its microbially
    habitable moon Europa. The same fate awaits Juno in February 2018.
    VIRGO
    VIRGO --- ---
    Our Solar System’s “shocking” origin | Carnegie Institution for Science
    https://carnegiescience.edu/news/our-solar-system%E2%80%99s-%E2%80%9Cshocking%E2%80%9D-origin

    According to one longstanding theory, our Solar System's formation was triggered by a shock wave from an exploding supernova. The shock wave injected material
    from the exploding star into a neighboring cloud of dust and gas, causing it to collapse in on itself and form the Sun and its surrounding planets.

    New work from Carnegie's Alan Boss offers fresh evidence supporting this theory, modeling the Solar System's formation beyond the initial cloud collapse and
    into the intermediate stages of star formation. It is published by the Astrophysical Journal.

    VIRGO
    VIRGO --- ---
    Reflections from an Alien World | Tiffany Jansen
    https://www.youtube.com/watch?v=_A9CfEEXMqQ
    VIRGO
    VIRGO --- ---
    VIRGO
    VIRGO --- ---
    New Space Simulations Show What Happens When Neutron Star, Black Hole Collide | Berkeley Lab
    http://newscenter.lbl.gov/2017/08/02/new-space-simulations-neutron-star-black-hole-mergers/

    Berkeley Lab scientists develop detailed models that provide new views of cataclysmic events in space

    Now that scientists can detect the wiggly distortions in space-time created by the merger of massive black holes,
    they are setting their sights on the dynamics and aftermath of other cosmic duos that unify in catastrophic collisions.

    Working with an international team, scientists at the Department of Energy’s Lawrence Berkeley National Laboratory
    (Berkeley Lab) have developed new computer models to explore what happens when a black hole joins with a neutron star –
    the superdense remnant of an exploded star.

    VIRGO
    VIRGO --- ---
    NRL Brightens Perspective of Mysterious Mini-Halos - U.S. Naval Research Laboratory
    https://www.nrl.navy.mil/...ia/news-releases/2017/NRL-Brightens-Perspective-of-Mysterious-Mini-Halos

    The largest gravitationally bound objects in the universe are galaxy clusters that form at the intersection of cosmic web filaments.
    These entities are shaped and grow through massive collisions as material streams into their gravitational pull. Within the heart
    of some galaxy clusters are mysterious and little known radio mini-halos. These rare, dispersed, and steep-spectrum (brighter at
    low frequencies) radio sources surround a bright central radio galaxy and are highly luminous at radio wavelengths.

    XCHAOS
    XCHAOS --- ---
    :: OSEL.CZ :: - Způsobují rádiové záblesky hvězdy z temné hmoty padající do černých děr?
    http://www.osel.cz/...9-zpusobuji-radiove-zablesky-hvezdy-z-temne-hmoty-padajici-do-cernych-der.html
    Fast radio bursts may be dark matter ‘stars’ hitting black holes | New Scientist
    https://www.newscientist.com/...2527-fast-radio-bursts-may-be-dark-matter-stars-hitting-black-holes/
    VIRGO
    VIRGO --- ---
    What Would It Take To Completely Sterilize the Earth? - The Atlantic
    https://www.theatlantic.com/.../2017/07/what-would-it-take-to-completely-sterilize-the-earth/533613/

    Three astrophysicists calculate that even huge asteroids and exploding stars probably wouldn’t wipe out all life.

    The odds of finding life on another planet hinge on the answers to two big questions. First, how often does life arise? Second, once it does arise,
    how likely is it to persist without being completely wiped out? The first question is extremely difficult, especially since we have exactly one example
    of a life-spawning planet. But the second question is easier to answer—at least for Earth—and a trio of astrophysicists have given it a shot.

    In a paper delightfully titled “The Resilience of Life to Astrophysical Events,” David Sloan and Rafael Alves Batista, both from the University of Oxford,
    and Avi Loeb, from Harvard University, estimated the odds that a space-borne catastrophe like an incoming asteroid would completely sterilize the Earth.
    Reassuringly, they think those odds are astronomically low—about one in 10 million for every billion years. “The conclusion we come to is that life, once it
    starts anywhere, is hard to eradicate,” Sloan says. In other words: Life finds a way (even if you bludgeon it with a giant space rock or an exploding star).

    To be clear, the three researchers aren’t concerned with the fate of humans—a fragile, fleshy species that, in Loeb’s words, can be “killed by climate change
    or affected by bad politics.” Instead, the trio wanted to know what it would take to wipe out all life on the planet. And to do that, they focused on the world’s
    hardiest animals—the tardigrades.

    VIRGO
    VIRGO --- ---
    'Weird! Signal' Mystery Solved!
    https://www.youtube.com/watch?v=OIQNSEADNlA
    VIRGO
    VIRGO --- ---
    http://www.nature.com/news/clues-emerge-in-mystery-of-flickering-quasars-1.22376

    Some of the Universe's most luminous objects have disappeared much faster than expected

    Some of the brightest objects in the Universe — quasars — are vanishing rapidly. Astronomers now think that they understand
    this mysterious behaviour, and the answer could help them to explain how galaxies such as the Milky Way evolve.

    Quasars are supermassive black holes at the centres of galaxies fed by huge quantities of gas that shine across the visible Universe.
    Astronomers have long thought that quasars persist for millions of years before dimming slowly over tens of thousands of years. But
    in 2014, Stephanie LaMassa, an astronomer now at the Space Telescope Science Institute in Baltimore, Maryland, discovered a quasar
    that seemed to disappear in less than ten years. That’s a blink of an eye, astronomically speaking.

    Researchers struggled to explain the oddity. Perhaps a massive dust cloud passed in front of the quasar’s bright beacon and momentarily
    blocked its light. Or maybe a star passed too close to the black hole and was rapidly torn apart, causing a bright flare that scientists
    mistook for a quasar. It seemed physically impossible that such a bright object could fade in such a short time.

    The discovery set in motion the hunt for more of these ‘changing-look’ quasars. The search has identified dozens of these mysterious
    beasts, some of which have dimmed more dramatically than the first. The two studies published this month on the preprint server arXiv
    suggest that these quasars blaze out of existence because the amount of gas and dust flowing through their accretion disks - the swirl
    of hot matter that encircles a black hole - drops dramatically. In effect, the black hole starves.
    VIRGO
    VIRGO --- ---
    First Support for a Physics Theory of Life | Quanta Magazine
    https://www.quantamagazine.org/first-support-for-a-physics-theory-of-life-20170726/

    Take chemistry, add energy, get life. The first tests of Jeremy England’s provocative
    origin-of-life hypothesis are in, and they appear to show how order can arise from nothing.

    VIRGO
    VIRGO --- ---
    The Soyuz MS-05 rocket is launched with Expedition 52 flight engineer Sergei Ryazanskiy of Roscosmos, flight engineer Randy Bresnik of NASA,
    and flight engineer Paolo Nespoli of ESA (European Space Agency), Friday, July 28, 2017 at the Baikonur Cosmodrome in Kazakhstan. Ryazanskiy,
    Bresnik, and Nespoli will spend the next four and a half months living and working aboard the International Space Station.

    VIRGO
    VIRGO --- ---
    https://www.nasa.gov/...oddard/2017/nasa-finds-moon-of-saturn-has-chemical-that-could-form-membranes

    NASA scientists have definitively detected the chemical acrylonitrile in the atmosphere of Saturn’s moon Titan,
    a place that has long intrigued scientists investigating the chemical precursors of life.

    On Earth, acrylonitrile, also known as vinyl cyanide, is useful in the manufacture of plastics. Under the harsh conditions of
    Saturn’s largest moon, this chemical is thought to be capable of forming stable, flexible structures similar to cell membranes.
    Other researchers have previously suggested that acrylonitrile is an ingredient of Titan’s atmosphere, but they did not report
    an unambiguous detection of the chemical in the smorgasbord of organic, or carbon-rich, molecules found there.

    A Titan Discovery
    https://www.youtube.com/watch?v=GiYIRzeL5z0
    VIRGO
    VIRGO --- ---
    Northolt Branch Observatories - Possible supernova 2017fro

    AT 2017fro | Transient Name Server
    https://wis-tns.weizmann.ac.il/object/2017fro

    VIRGO
    VIRGO --- ---
    New Study Shows Dark Matter Isn't Warm And Fuzzy
    https://www.forbes.com/...n/2017/07/28/new-study-shows-dark-matter-isnt-warm-and-fuzzy/#2cf9f6487135

    The most models assume that dark matter is cold. In this case, cold vs warm refers to the speed at which dark matter particles typically move.
    In cold dark matter models, the particles are relatively heavy, with a mass similar to that of protons or more. Because of their high mass, these
    dark matter particles would move relatively slowly, at much the same speed as the gas and dust in our galaxy. Neutrinos, on the other hand, are
    warm dark matter. Neutrinos don't interact strongly with light, and they do have mass, so they meet the basic requirement of dark matter.
    Kliknutím sem můžete změnit nastavení reklam