• úvod
  • témata
  • události
  • tržiště
  • diskuze
  • nástěnka
  • přihlásit
    registrace
    ztracené heslo?
    VIRGOCosmos In Brief - Aktualní novinky vesmírného výzkumu v kostce
    VIRGO
    VIRGO --- ---
    What If the Big Bang Wasn't the Beginning? New Study Proposes Alternative
    https://www.space.com/38982-no-big-bang-bouncing-cosmology-theory.html

    ..."The Big Bang as the initial singularity is only a speculation," Silva Neves told Space.com.
    He said that "there are many observations in cosmology" that support the hypothesis that the
    universe went through a period of rapid expansion, but that there is no direct evidence that
    this expansion started with a singularity.

    In a paper published Aug. 29 in the journal General Relativity and Gravitation, Silva Neves,
    a researcher at the Mathematics, Statistics & Scientific Computation Institute (IMECC-UNICAMP)
    of the University of Campinas, in Brazil, proposes an alternative cosmological model that does
    away with the necessity of this original singularity. His model includes a concept known as
    bouncing cosmology.

    VIRGO
    VIRGO --- ---
    https://www.swri.org/press-release/collisions-after-moon-formation-remodeled-early-earth

    Southwest Research Institute scientists recently modeled the protracted period of bombardment following the Moon’s formation, when leftover planetesimals
    pounded the Earth. Based on these simulations, scientists theorize that moon-sized objects delivered more mass to the Earth than previously thought.

    Early in its evolution, Earth sustained an impact with another large object, and the Moon formed from the resulting debris ejected into an Earth-orbiting
    disk. A long period of bombardment followed, the so-called “late accretion,” when large bodies impacted the Earth delivering materials that were accreted
    or integrated into the young planet.

    “We modeled the massive collisions and how metals and silicates were integrated into Earth during this ‘late accretion stage,’ which lasted for hundreds
    of millions of years after the Moon formed,” said SwRI’s Dr. Simone Marchi, lead author of a Nature Geoscience paper outlining these results. “Based on
    our simulations, the late accretion mass delivered to Earth may be significantly greater than previously thought, with important consequences for
    the earliest evolution of our planet.”

    Previously, scientists estimated that materials from planetesimals integrated during the final stage of terrestrial planet formation made up about half
    a percent of the Earth’s present mass. This is based on the concentration of highly “siderophile” elements — metals such as gold, platinum and iridium,
    which have an affinity for iron — in the Earth’s mantle. The relative abundance of these elements in the mantle points to late accretion, after Earth’s
    core had formed. But the estimate assumes that all highly siderophile elements delivered by the later impacts were retained in the mantle.

    BLACKHEAD
    BLACKHEAD --- ---
    VIRGO: Measured in the time domain? Or how?
    VIRGO
    VIRGO --- ---
    Strejda Albert o5 bez ztráty kytičky
    In a first, Galileo’s gravity experiment is re-created in space | Science News
    https://www.sciencenews.org/article/first-galileo-gravity-experiment-re-created-space-einstein

    Galileo’s most famous experiment has taken a trip to outer space. The result? Einstein was right yet again.
    The experiment confirms a tenet of Einstein’s theory of gravity with greater precision than ever before.

    According to science lore, Galileo dropped two balls from the Leaning Tower of Pisa to show that they fell at the same rate no matter their composition.
    Although it seems unlikely that Galileo actually carried out this experiment, scientists have performed a similar, but much more sensitive experiment in
    a satellite orbiting Earth. Two hollow cylinders within the satellite fell at the same rate over 120 orbits, or about eight days’ worth of free-fall time,
    researchers with the MICROSCOPE experiment report Dec 4 in Physical Review Letters. The cylinders’ accelerations match within two-trillionths of a percent.

    VIRGO
    VIRGO --- ---
    Snellen - Exoplanets and the search for extraterrestrial life
    https://www.youtube.com/watch?time_continue=2&v=ZNkhILRp354
    VIRGO
    VIRGO --- ---
    VLT’s SPHERE spies rocky worlds | ESO United Kingdom
    http://www.eso.org/public/unitedkingdom/images/potw1749a/

    These images were taken by ESO’s SPHERE (Spectro-Polarimetric High-contrast Exoplanet REsearch) instrument, installed on ESO’s Very Large Telescope
    (VLT) at the Paranal Observatory, Chile. These strikingly-detailed views reveal four of the millions of rocky bodies in the main asteroid belt,
    a ring of asteroids between Mars and Jupiter that separates the rocky inner planets of the Solar System from the gaseous and icy outer planets.

    VIRGO
    VIRGO --- ---
    Astronomer’s map reveals location of mysterious fast-moving gas | University News : The University of Western Australia
    http://www.news.uwa.edu.au/...rnational/astronomer-s-map-reveals-location-mysterious-fast-moving-gas

    An Australian scientist has created the most detailed map ever of clouds of high-velocity gas in the Universe around us.

    The map covers the entire sky and shows curious clouds of neutral hydrogen gas that are moving at a different speed to
    the normal rotation of the Milky Way.

    It was created by astronomer Dr Tobias Westmeier, from The University of Western Australia node of the International Centre
    for Radio Astronomy Research, and published today in the leading journal Monthly Notices of the Royal Astronomical Society.

    Dr Westmeier said the map suggests that at least 13 per cent of the sky is covered by high-velocity clouds.

    VIRGO
    VIRGO --- ---
    Metal asteroid Psyche is all set for an early visit from NASA
    https://theconversation.com/metal-asteroid-psyche-is-all-set-for-an-early-visit-from-nasa-88044

    Three times further away from the sun than the Earth lies an enormous lump of metal. Around 252km in diameter,
    the metallic “M-class” asteroid 16 Psyche is the target of NASA’s next mission to the belt of giant rocks that
    encircles the inner solar system. And the space agency now plans to visit it much sooner than originally planned.

    Not only has the launch has been brought forward one year to the summer of 2022, but NASA’s scientists have also
    found a way to get to Psyche (pronounced SYKe-ee) much faster by taking a more efficient trajectory. The new route
    means the Psyche spacecraft won’t have to swing around the Earth to build up speed and won’t pass as close to the
    sun, so it needs less heat protection. It is now due to arrive in 2026, four years earlier than the original timeline.

    BROUKOID
    BROUKOID --- ---
    VIRGO: obavam se ze to je ale spatne - minimalne ten lunochod je moc malej. Ve skutecnosti ma prumer "talire" cca 2m.
    VIRGO
    VIRGO --- ---
    Recipe for a comet | Max Planck Society
    https://www.mpg.de/11813538/chemical-elements-rosetta-comet-67p?c=2249

    Rearchers analyse which chemical elements make up comet 67P/Churyumov-Gerasimenko

    The dust that comet 67P/Churyumov-Gerasimenko emits into space consists to about one half of organic molecules.
    The dust also belongs to the most pristine and carbon-rich material known in our solar system; it has hardly
    changed since its birth. These are the results of the COSIMA team, an instrument onboard the Rosetta spacecraft,
    which investigated the comet. In their current study, the involved researchers including scientists from the Max
    Planck Institute for Solar System Research analyze as comprehensively as never before, what chemical elements
    constitute cometary dust.

    VIRGO
    VIRGO --- ---
    https://www.nasa.gov/image-feature/jpl/pia21972/jupiter-blues

    The Juno spacecraft captured this image when the spacecraft was only 11,747 miles (18,906 kilometers) from the tops of Jupiter’s clouds —
    that’s roughly as far as the distance between New York City and Perth, Australia. The color-enhanced image, which captures a cloud system
    in Jupiter’s northern hemisphere, was taken on Oct. 24, 2017 at 10:24 a.m. PDT (1:24 p.m. EDT) when Juno was at a latitude of 57.57 degrees
    (nearly three-fifths of the way from Jupiter’s equator to its north pole) and performing its ninth close flyby of the gas giant planet.

    The spatial scale in this image is 7.75 miles/pixel (12.5 kilometers/pixel).

    Citizen scientists Gerald Eichstädt and Seán Doran processed this image using data from the JunoCam imager.

    VIRGO
    VIRGO --- ---
    The Mysterious Star MWC349su201744 | www.cfa.harvard.edu/
    https://www.cfa.harvard.edu/news/su201744

    Molecular clouds in interstellar space can sometimes produce natural masers (the radio wavelength analogs of lasers) that shine with
    bright, narrow beams of radiation. Regions of active star formation generate some of the most spectacular such masers -- in one case
    radiating as much energy in a single spectral line as does our Sun in its entire visible spectrum. In these sources, the maser
    radiation comes from molecules like water or OH that are excited by collisions and the radiation environment around the young stars.

    VIRGO
    VIRGO --- ---
    Giant Black Hole Pair Photobombs Andromeda Galaxy | NASA
    https://www.nasa.gov/...on_pages/chandra/news/giant-black-hole-pair-photobombs-andromeda-galaxy.html

    It seems like even black holes can’t resist the temptation to insert themselves unannounced into photographs. A cosmic photobomb found as a background
    object in images of the nearby Andromeda galaxy has revealed what could be the most tightly coupled pair of supermassive black holes ever seen.

    Astronomers made this remarkable discovery using X-ray data from NASA’s Chandra X-ray Observatory and optical data from ground-based telescopes, Gemini-
    North in Hawaii and the Caltech’s Palomar Transient Factory in California.

    This unusual source, called LGGS J004527.30+413254.3 (J0045+41 for short), was seen in optical and X-ray images of Andromeda, also known as M31. Until
    recently, scientists thought J0045+41 was an object within M31, a large spiral galaxy located relatively nearby at a distance of about 2.5 million light
    years from Earth. The new data, however, revealed that J0045+41 was actually at a much greater distance, around 2.6 billion light years from Earth.

    “We were looking for a special type of star in M31 and thought we had found one,” said Trevor Dorn-Wallenstein of the University of Washington in Seattle,
    WA, who led the paper describing this discovery. “We were surprised and excited to find something far stranger!”

    Even more intriguing than the large distance of J0045+41 is that it likely contains a pair of giant black holes in close orbit around each other.
    The estimated total mass for these two supermassive black holes is about two hundred million times the mass of our Sun.

    Previously, a different team of astronomers had seen periodic variations in the optical light from J0045+41, and, believing it to be a member of M31,
    classified it as a pair of stars that orbited around each other about once every 80 days.

    VIRGO
    VIRGO --- ---
    Hydrothermal vent experiments bring Enceladus to Earth - Astrobiology Magazine
    https://www.astrobio.net/news-exclusive/hydrothermal-vent-experiments-bring-enceladus-earth/

    Laboratory experiments on Earth can now simulate the conditions under which life might emerge on Saturn’s moon Enceladus, as well as other icy alien worlds,
    according to new research published in the September 2017 issue of the journal Astrobiology.

    Since there is life virtually wherever there is water on Earth, researchers looking for alien life often focus on planets in the habitable zones of stars,
    which are the regions around stars where it is warm enough for worlds to possess water on their surfaces. However, in the past few decades, scientists have
    increasingly found evidence for oceans – and, potentially, life – hidden under the icy crusts of places such as Jupiter’s moons Europa, Ganymede and Callisto,
    and Saturn’s moons Enceladus and Titan.

    On Earth, life is often thought to have originated near hydrothermal vents, which include hot springs on land, as well as fissures near undersea volcanoes.
    Much research has suggested that icy moons might also host active hydrothermal vents on their ocean floors. Enceladus is of particular interest because data
    from NASA’s Cassini spacecraft suggests there is activity within its ocean involving temperatures exceeding 90 degrees Celsius (194 degrees Fahrenheit),
    which in turn hints at geothermal heating by hydrothermal vents.

    VIRGO
    VIRGO --- ---
    Scientists reduce the chances of life on exoplanets in so-called habitable zones around red stars
    https://www.princeton.edu/...sts-reduce-chances-life-exoplanets-so-called-habitable-zones-around-red

    Is there life beyond Earth in the cosmos? Astronomers looking for signs have found that our Milky Way galaxy teems with exoplanets, some with conditions that could be right
    for extraterrestrial life. Such worlds orbit stars in so-called “habitable zones,” regions where planets could hold liquid water that is necessary for life as we know it.

    However, the question of habitability is highly complex. Researchers led by space physicist Chuanfei Dong of the U.S. Department of Energy’s (DOE) Princeton Plasma Physics
    Laboratory (PPPL) and Princeton University have recently raised doubts about water on — and thus potential habitability of — frequently cited exoplanets that orbit red dwarfs,
    the most common stars in the Milky Way.

    In two papers in The Astrophysical Journal Letters, the scientists develop models showing that the stellar wind — the constant outpouring of charged particles that sweep out
    into space — could severely deplete the atmosphere of such planets over hundreds of millions of years, rendering them unable to host surface-based life as we know it.

    “Traditional definition and climate models of the habitable zone consider only the surface temperature,” Dong said. “But the stellar wind can significantly contribute to
    the long-term erosion and atmospheric loss of many exoplanets, so the climate models tell only part of the story.”

    To broaden the picture, the first paper looks at the timescale of atmospheric retention on Proxima Centauri b (PCb), which orbits the nearest star to our solar system,
    some four light years away. The second paper questions how long oceans could survive on “water worlds” — planets thought to have seas that could be hundreds of miles deep.
    VIRGO
    VIRGO --- ---
    Tak tohle bude (doufám) velký! Sledoval jsem přípravy už skoro 2 měsíce, zítra ve 20:05 h to vypukne na čt24:

    Hyde Park Civilizace - Evropská jižní observatoř v chilské poušti Atacama

    La Silla, Paranal a ALMA. Observatoře ESO, které provozují nejmodernější teleskopy na planetě.
    S lidmi, kteří je řídí, natáčel přímo na místě Daniel Stach. Sobotní Hyde Park Civilizace bude
    celý z téměř opačné strany Země, z míst, ze kterých je jeden z nejlepších výhledů na Jižní oblohu...
    Dívejte se v sobotu ve 20:05 na ČT24.

    Hyde Park Civilizace: Evropská jižní observatoř v chilské poušti Atacama — Česká televize
    http://www.ceskatelevize.cz/porady/10441294653-hyde-park-civilizace/217411058091202/

    https://www.facebook.com/hydeparkcivilizace/

    VIRGO
    VIRGO --- ---
    https://www.nasa.gov/press-release/goddard/2017/dance-preserves-oceans

    Heat generated by the gravitational pull of moons formed from massive collisions could extend the lifetimes of liquid water oceans beneath the surface
    of large icy worlds in our outer solar system, according to new NASA research. This greatly expands the number of locations where extraterrestrial life
    might be found, since liquid water is necessary to support known forms of life and astronomers estimate there are dozens of these worlds.
    VIRGO
    VIRGO --- ---
    Pěkný render. Srovnání velikostí některých kosmických roverů, sond a nosičů. Autor: Álvaro Gracia Montoya

    Space vehicles size Comparison
    https://www.youtube.com/watch?v=FiCreWWkDiI
    VIRGO
    VIRGO --- ---
    Are Spinning Black Holes Louder?
    http://aasnova.org/2017/11/29/are-spinning-black-holes-louder/

    Some distant active galaxies are louder in radio wavelengths than others. A new study explores whether
    this difference could be due to how quickly the supermassive black holes at their centers are spinning.

    Kliknutím sem můžete změnit nastavení reklam