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    VIRGOCosmos In Brief - Aktualní novinky vesmírného výzkumu v kostce
    VIRGO
    VIRGO --- ---
    ESA Science & Technology: Gaia data help prepare for a rare celestial alignment of Neptune's largest moon
    http://sci.esa.int/...ia-data-help-prepare-for-a-rare-celestial-alignment-of-neptune-s-largest-moon/

    On 5 October 2017, the largest moon of Neptune will pass in front of a distant star. This rare event will temporarily block the star's light from Earth and provide
    an excellent opportunity to study the moon's intriguing atmosphere. Data from ESA's Gaia mission is allowing astronomers to precisely plan their observations.

    VIRGO
    VIRGO --- ---
    +1
    How I discovered the origins of the cigar-shaped alien 'asteroid' 'Oumuamua
    https://theconversation.com/...covered-the-origins-of-the-cigar-shaped-alien-asteroid-oumuamua-89577

    With a hyperbolic trajectory around the Sun, `Oumuamua is the first confirmed interstellar object. However, its origin is poorly known. By simulating the orbits of 0.23 million local stars,
    we find 109 encounters with periastron less than 5 pc. `Oumuamua's low peculiar velocity is suggestive of its origin from a young stellar association with similar velocity. In particular,
    we find that `Oumuamua would have had slow encounters with at least five young stars belonging to the Local Association thus suggesting these as plausible sites for formation and ejection.
    In addition to an extremely elongated shape, the available observational data for `Oumuamua indicates a red colour suggestive of a potentially organic-rich and activity-free surface.

    [1711.08800] `Oumuamua as a messenger from the Local Association
    https://arxiv.org/abs/1711.08800

    VIRGO
    VIRGO --- ---
    https://www.nasa.gov/feature/spend-next-new-year-s-eve-with-new-horizons

    In just under a year – shortly after midnight Eastern Time on Jan. 1, 2019 – NASA’s New Horizons spacecraft will buzz by the most primitive and most distant object ever explored.
    New Horizons’ encounter with Kuiper Belt object 2014 MU69, which orbits a billion miles beyond Pluto, will offer the first close-up look at such a pristine building block of
    the solar system – and will be performed in a region of deep space that was practically unknown just a generation ago.

    VIRGO
    VIRGO --- ---
    Library of galaxy histories reconstructed from motions of stars | Instituto de Astrofísica de Andalucía - CSIC
    http://www.iaa.es/en/news/library-galaxy-histories-reconstructed-motions-stars

    The CALIFA survey allows to map the orbits of the stars of a sample of 300 galaxies, a fundamental information to know how they formed and evolved.

    Just like the Sun is moving in our Galaxy, the Milky Way, all the stars in galaxies are moving, but with very different orbits: some of the stars have strong rotations,
    while others may be moving randomly with no clear rotation. Comparing the fraction of stars on different orbits we can find out how galaxies form and evolve. An international
    team of astronomers has derived directly, for the first time, the orbital distribution of a galaxy sample, containing more than 300 galaxies of the local universe. The results,
    published in Nature Astronomy, are based on the CALIFA survey, a project developed at Calar Alto Observatory and conceived from the Institute of Astrophysics of Andalusia.

    Galaxies are largest structures in the universe, and scientist study how they evolve to understand the history of the universe. Galaxy formation entails the hierarchical
    assembly of halos of dark matter (a type of matter that has not been directly observed and whose existence and properties are inferred from its gravitational effects), along
    with the condensation of normal matter at the halos´ center, where stellar formation takes place. Stars that formed from a settled, thin gas disk and then lived though dynamically
    quiescent times will present near circular orbits, while stars with random motions are the result of turbulent environments, either at birth or later, with galactic mergers.

    Proyecto CALIFA: arqueología galáctica en 3D
    https://www.youtube.com/watch?v=w67yS68qwto


    Thus, the motions of stars in a galaxy are like a history book, they record the information about their birth and growth environment, and it may tell us how the galaxy was formed.
    "However, the motion of each single star is not directly observable in external galaxies. External galaxies are projected on the observational plane as an image and we cannot resolve
    the discrete stars in it -says Ling Zhu, researcher from the Max Planck Institute for Astronomy who leads the study-. The CALIFA survey uses a recently developed technique, integral
    field spectroscopy, which can observe the external galaxies in such a way that it provides the overall motion of stars. Thus, we can get kinematic maps of each galaxy."

    The researchers then build models for each galaxy by superposing stars on different types of orbits. By constraining the model with the observed image and kinematic maps, they can
    find out the amount of stars moving on different types of orbits in each galaxy. They call it the stellar orbit distribution and, for this study, the team has built models for all
    300 galaxies, representative of the general properties of galaxies in the local universe.

    VIRGO
    VIRGO --- ---
    +2
    Pardon, je to delší, ale odpověď v komentu je také zajímavá.

    How Fast Is Dark Matter?
    http://aasnova.org/2018/01/02/how-fast-is-dark-matter/

    Our galaxy is embedded in a cloud of dark matter, thought to consist of tiny particles traveling along orbits through the halo. These dark matter particles permeate all regions of the galaxy,
    extending far beyond the edge of the bright central spiral, but also orbiting through our solar system, and even passing right through the Earth. This is why scientists build giant detectors,
    hoping to trap some of these dark matter particles as they pass by. So far, these experiments have not detected dark matter, but that lack of detection is actually quite interesting. Finding
    out what dark matter is not, and thereby narrowing down the possibilities, is an important step towards revealing the true nature of these mysterious particles.

    In order to really understand what it means when a detecter does not see dark matter, it is important to have a clear prediction for how much dark matter should be detected. For example, if we
    expect very few dark matter particles to pass through the Earth in a given amount of time, then maybe the lack of detections over a few years doesn’t actually mean those particles don’t exist.
    One essential piece of information in this prediction is the velocity of dark matter particles as they orbit past our solar system.

    So, how can we determine the speed of these particles that we haven’t even directly detected? Well, let’s look back at where these particles actually come from. Dark matter halos grow over time
    by consuming other dark matter halos. This process is called hierarchical structure formation. The Milky Way is continuously pulling in smaller galaxies and then tearing them apart, thoroughly
    mixing their stars and dark matter particles into the Milky Way halo (Figure 1).

    This understanding of the origin of these particles reveals an important piece of information: when dark matter particles join the Milky Way, they are often accompanied by stars. This is great
    news, because stars, unlike dark matter particles, are not invisible, and we can directly measure their velocities. If we can confirm that dark matter particles tend to move at similar
    velocities to their stellar companions, then this problem of determining the local dark matter velocity is much simpler!



    Odpověď: Chris Reeves (jde o citaci)

    ... in some ways, the discoveries made in recent decades have raised as many new questions as they have answered.

    One of the most vexing gets at the heart of what our universe is actually made of. Cosmological observations have determined the average density of matter
    in our universe to very high precision. But this density turns out to be much greater than can be accounted for with ordinary atoms.

    After decades of measurements and debate, we are now confident that the overwhelming majority of our universe's matter -- about 84 percent -- is not made
    up of atoms, or of any other known substance. Although we can feel the gravitational pull of this other matter, and clearly tell that it's there, we simply
    do not know what it is. This mysterious stuff is invisible, or at least nearly so. For lack of a better name, we call it 'dark matter.' But naming something
    is very different from understanding it.

    For almost as long as we've known that dark matter exists, physicists and astronomers have been devising ways to try to learn what it's made of. They've built
    ultra-sensitive detectors, deployed in deep underground mines, in an effort to measure the gentle impacts of individual dark matter particles colliding with atoms.

    They've built exotic telescopes -- sensitive not to optical light but to less familiar gamma rays, cosmic rays and neutrinos -- to search for the high-energy
    radiation that is thought to be generated through the interactions of dark matter particles.

    And we have searched for signs of dark matter using incredible machines which accelerate beams of particles -- typically protons or electrons -- up to the highest
    speeds possible, and then smash them into one another in an effort to convert their energy into matter. The idea is these collisions could create new and exotic
    substances, perhaps including the kinds of particles that make up the dark matter of our universe.

    As recently as a decade ago, most cosmologists -- including myself -- were reasonably confident that we would soon begin to solve the puzzle of dark matter.
    After all, there was an ambitious experimental program on the horizon, which we anticipated would enable us to identify the nature of this substance and to begin
    to measure its properties. This program included the world's most powerful particle accelerator -- the Large Hadron Collider – as well as an array of other new
    experiments and powerful telescopes.

    But things did not play out the way that we expected them to. Although these experiments and observations have been carried out as well as or better than we could
    have hoped, the discoveries did not come.

    Over the past 15 years, for example, experiments designed to detect individual particles of dark matter have become a million times more sensitive, and yet no signs
    of these elusive particles have appeared. And although the Large Hadron Collider has by all technical standards performed beautifully, with the exception of the Higgs
    boson, no new particles or other phenomena have been discovered.

    The stubborn elusiveness of dark matter has left many scientists both surprised and confused. We had what seemed like very good reasons to expect particles of dark
    matter to be discovered by now. And yet the hunt continues, and the mystery deepens.

    In many ways, we have only more open questions now than we did a decade or two ago. And at times, it can seem that the more precisely we measure our universe,
    the less we understand it. Throughout the second half of the 20th century, theoretical particle physicists were often very successful at predicting the kinds of
    particles that would be discovered as accelerators became increasingly powerful. It was a truly impressive run.

    But our prescience seems to have come to an end -- the long-predicted particles associated with our favorite and most well-motivated theories have stubbornly refused
    to appear. Perhaps the discoveries of such particles are right around the corner, and our confidence will soon be restored. But right now, there seems to be little
    support for such optimism.

    In response, droves of physicists are going back to their chalkboards, revisiting and revising their assumptions. With bruised egos and a bit more humility, we are
    desperately attempting to find a new way to make sense of our world."

    That last sentence is really kind of peculiar. Where are these "droves of physicists" who are "going back to their chalkboards"?

    I'm having trouble seeing them.
    VIRGO
    VIRGO --- ---
    The Geometry of Nuclear Black Hole Accretion Diskssu201750 | www.cfa.harvard.edu/
    https://www.cfa.harvard.edu/news/su201750

    CfA astronomer Anna Pancoast and a team of her colleagues analyzed reverberation mapping data of four AGN to study their geometries and, in particular,
    the volume of hot gas known for its rapid motions, the so-called broad line region because the spectral lines have widths corresponding to as much as
    three thousand kilometers per second. The scientists find the geometry of this gas, at least in these four AGN, is well-described as coming from thick
    disks seen nearly face-on, with median radii from about 1600 AU to 4000 AU, and each with a black hole whose mass is about seventy million solar-masses
    (with an estimated precision for each one of about 50%). The new work was successful in modeling the observations and nearly doubles the size of the AGN
    sample modeled with this technique. The sample is still small, however, and more observations are being planned.

    VIRGO
    VIRGO --- ---
    +4
    Alien megastructure not the cause of dimming of the 'most mysterious star in the universe'
    https://phys.org/news/2018-01-alien-megastructure-dimming-mysterious-star.html

    A team of more than 200 researchers, including Penn State Department of Astronomy and Astrophysics Assistant Professor Jason Wright and led by Louisiana State University's
    Tabetha Boyajian, is one step closer to solving the mystery behind the "most mysterious star in the universe." KIC 8462852, or "Tabby's Star," nicknamed after Boyajian, is
    otherwise an ordinary star, about 50 percent bigger and 1,000 degrees hotter than the Sun, and about than 1,000 light years away. However, it has been inexplicably dimming
    and brightening sporadically like no other. Several theories abound to explain the star's unusual light patterns, including that an alien megastructure is orbiting the star.

    he mystery of Tabby's Star is so compelling that more than 1,700 people donated over $100,000 through a Kickstarter campaign in support of dedicated ground-based telescope
    time to observe and gather more data on the star through a network of telescopes around the world. As a result, a body of data collected by Boyajian and colleagues in
    partnership with the Las Cumbres Observatory is now available in a new paper in The Astrophysical Journal Letters.

    "We were hoping that once we finally caught a dip happening in real time we could see if the dips were the same depth at all wavelengths. If they were nearly the same, this
    would suggest that the cause was something opaque, like an orbiting disk, planet, or star, or even large structures in space" said Wright, who is a co-author of the paper,
    titled "The First Post-Kepler Brightness Dips of KIC 8462852." Instead, the team found that the star got much dimmer at some wavelengths than at others.

    "Dust is most likely the reason why the star's light appears to dim and brighten. The new data shows that different colors of light are being blocked at different intensities.
    Therefore, whatever is passing between us and the star is not opaque, as would be expected from a planet or alien megastructure," Boyajian said.

    VIRGO
    VIRGO --- ---
    Supermassive black holes control star formation in large galaxies
    https://news.ucsc.edu/2018/01/supermassive-black-holes.html

    Astronomers find close correlation between the mass of a galaxy's central black hole and its star formation history

    Young galaxies blaze with bright new stars forming at a rapid rate, but star formation eventually shuts down as a galaxy evolves. A new study, published
    January 1, 2018, in Nature, shows that the mass of the black hole in the center of the galaxy determines how soon this "quenching" of star formation occurs.

    Every massive galaxy has a central supermassive black hole, more than a million times more massive than the sun, revealing its presence through its gravitational
    effects on the galaxy's stars and sometimes powering the energetic radiation from an active galactic nucleus (AGN). The energy pouring into a galaxy from an active
    galactic nucleus is thought to turn off star formation by heating and dispelling the gas that would otherwise condense into stars as it cooled.

    XCHAOS
    XCHAOS --- ---
    The Plasma Magnet Drive: A Simple, Cheap Drive for the Solar System and Beyond
    https://www.centauri-dreams.org/?p=39048
    JAYME
    JAYME --- ---
    +1
    Red Iron Models - scale models of the Soviet construction and road machinery
    http://www.redironmodels.com/index.html

    jen takova zajimavost, ruska firma Red Iron Models vyrabi resinove modely 1/35 Sputniku, Vostoku a Lunochodu. dale tam maji nejaky crowfunding, v ramci ktereho nejvetsim backerum nabizi exkluzivni model Hubblova teleskopu, taky 1/35.

    uz drive jsem zvazoval a pak radsi vzdal Voyager od Hasegawy, hlavne kvuli dlouhym stozarum, ktere bylo potreba slozit z leptu a pak jeste stocit do sroubovic, coz ani nevim jestli jde
    ten Sputnik je dostatecne primitivni a mozna bych ho dal :)
    VIRGO
    VIRGO --- ---
    +1
    https://www.nasa.gov/...dard/2017/nasa-s-next-major-telescope-to-see-the-big-picture-of-the-universe

    Scheduled to launch in the mid-2020s, the Wide Field Infrared Survey Telescope (WFIRST) will function as Hubble’s wide-eyed cousin.
    While just as sensitive as Hubble's cameras, WFIRST's 300-megapixel Wide Field Instrument will image a sky area 100 times larger.
    This means a single WFIRST image will hold the equivalent detail of 100 pictures from Hubble.

    WFIRST Will See the Big Picture of the Universe
    https://www.youtube.com/watch?time_continue=1&v=Nu4DsKlKKMQ
    VIRGO
    VIRGO --- ---
    +2
    https://www.nasa.gov/feature/jpl/arecibo-radar-returns-with-asteroid-phaethon-images

    Arecibo’s radar images of Phaethon have resolutions as fine as about 250 feet (75 meters) per pixel.



    VIRGO
    VIRGO --- ---
    +1
    Sunlight holds the key to planet’s shine | University of Oxford
    http://www.ox.ac.uk/news/2017-12-22-sunlight-holds-key-planet%E2%80%99s-shine

    Changes in solar activity influence the colour and formation of clouds around the planet, researchers at Oxford and Reading universities found.

    The icy planet is second furthest from the sun in the solar system and takes 84 Earth years to complete a full orbit – one Uranian year.

    The researchers found that, once the planet’s long and strange seasons are taken into account, it appears brighter and dimmer over a cycle of 11 years.
    This is the regular cycle of solar activity which also affects sun spots.

    VIRGO
    VIRGO --- ---
    +1
    Cosmic Filament Probes Our Galaxy’s Giant Black Hole2017-35 | www.cfa.harvard.edu/
    https://www.cfa.harvard.edu/news/2017-35

    The center of our Galaxy has been intensely studied for many years, but it still harbors surprises for scientists.
    A snake-like structure lurking near our galaxy’s supermassive black hole is the latest discovery to tantalize astronomers.

    In 2016, Farhad Yusef-Zadeh of Northwestern University reported the discovery of an unusual filament near the center of
    the Milky Way Galaxy using the NSF’s Karl G. Jansky Very Large Array (VLA). The filament is about 2.3 light years long and
    curves around to point at the supermassive black hole, called Sagittarius A* (Sgr A*), located in the Galactic center.

    Now, another team of astronomers has employed a pioneering technique to produce the highest-quality image yet obtained
    of this curved object.

    VIRGO
    VIRGO --- ---
    Astronomers Shed Light on Formation of Black Holes and Galaxies W. M. Keck Observatory
    http://www.keckobservatory.org/recent/entry/quasar_galaxy

    Stars forming in galaxies appear to be influenced by the supermassive black hole at the center of the galaxy,
    but the mechanism of how that happens has not been clear to astronomers until now.

    In a study published today in The Astrophysical Journal, Wright, graduate student Andrey Vayner, and their colleagues
    examined the energetics surrounding the powerful winds generated by the bright, vigorous supermassive black hole
    (known as a “quasar”) at the center of the 3C 298 host galaxy, located approximately 9.3 billion light years away.

    VIRGO
    VIRGO --- ---
    +5
    James Webb Emerging From Chamber A
    https://www.youtube.com/watch?v=FgFkqCEntss


    Like in the classic holiday song, Webb’s “silver” sunshield and “gold” mirrors shimmer brightly in this image mashup.
    These are more than decorations for Webb, and their worth is measured by the scientific discoveries the telescope will make.
    https://www.nasa.gov/feature/goddard/2017/webb-telescopes-silver-and-gold-decorations

    VIRGO
    VIRGO --- ---
    +3
    !!
    A century of galaxy discrimination revealed by giant European astronomy survey - News - Cardiff University
    http://www.cardiff.ac.uk/...ury-of-galaxy-discrimination-revealed-by-giant-european-astronomy-survey

    A huge European astronomy survey, whose results are released today (21 December 2017), has revealed that the view of the Universe
    provided by traditional optical telescopes is seriously biased.

    The Herschel ATLAS (H-ATLAS) was a survey carried out by an international team led by researchers at Cardiff University with European Herschel
    Space Observatory in the far-infrared waveband, which consists of electromagnetic waves with wavelengths 200 times greater than optical light.

    VIRGO
    VIRGO --- ---
    https://www.nasa.gov/...e/goddard/2017/new-study-finds-winking-star-may-be-devouring-wrecked-planets

    A team of U.S. astronomers studying the star RZ Piscium has found evidence suggesting its strange, unpredictable
    dimming episodes may be caused by vast orbiting clouds of gas and dust, the remains of one or more destroyed planets.

    "Our observations show there are massive blobs of dust and gas that occasionally block the star's light and are probably
    spiraling into it," said Kristina Punzi, a doctoral student at the Rochester Institute of Technology (RIT) in New York
    and lead author of a paper describing the findings. "Although there could be other explanations, we suggest this material
    may have been produced by the break-up of massive orbiting bodies near the star."

    ‘Winking’ Star May Be Devouring Wrecked Planets
    https://www.youtube.com/watch?v=nf2oc6nMsn4
    VIRGO
    VIRGO --- ---
    +5
    Tak je to tu: Two finalists were just selected to further develop their mission concepts through 2018

    CAESAR – A mission to return a sample from the nucleus of a comet.
    Dragonfly – A drone-like rotorcraft to explore the prebiotic chemistry of Saturn’s moon Titan.

    https://www.nasa.gov/.../nasa-invests-in-concept-development-for-missions-to-comet-saturn-moon-titan

    VIRGO
    VIRGO --- ---
    +3
    Gigantické bubliny na povrchu rudého obra | ESO Česko
    http://www.eso.org/public/czechrepublic/news/eso1741/?lang

    Astronomové využívající dalekohled ESO/VLT poprvé v historii pozorovali strukturu granulace na povrchu vzdálené hvězdy – stárnoucího rudého obra
    π1 Gruis. Tento pozoruhodný nový snímek byl pořízen pomocí přístroje PIONIER. Odhaluje konvektivní buňky o průměru asi 120 milionů kilometrů tvořící
    povrchovou vrstvu mohutné hvězdy, která svou velikostí 350krát převyšuje Slunce. Výsledky byly publikovány v prestižním vědeckém časopise Nature.

    Kliknutím sem můžete změnit nastavení reklam