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    VIRGOCosmos In Brief - Aktualní novinky vesmírného výzkumu v kostce
    NEBULA
    NEBULA --- ---
    Astrophotographer Mike Killian took this image of Venus and the crescent moon on Dec. 2, 2016 from Toronto

    NEBULA
    NEBULA --- ---
    VIRGO: o bože úžasná fotka!
    ________________

    The crew is getting ready for a pair of spacewalks scheduled for this Friday and next Friday to upgrade the International Space Station’s power system. The two spacewalks will take place on the station’s right-side, or starboard, truss structure to replace and install new power equipment.

    Commander Shane Kimbrough and NASA astronaut Peggy Whitson will step outside for the first power maintenance spacewalk Friday at 7 a.m. EST. Kimbrough will be joined by European Space Agency astronaut Thomas Pesquet the following Friday for the second spacewalk. The three astronauts are reviewing spacewalk procedures, collecting tools and configuring cameras in the U.S. Quest airlock today.

    Robotics controllers remotely removed nickel-hydrogen batteries and installed new lithium-ion batteries on the starboard-4 truss over the holidays and into the New Year. The robotics work sets up the power maintenance work the spacewalkers will perform including replacing adapter plates and relocating the old batteries.

    The three astronauts and their fellow cosmonauts still had time for a variety of science work and standard orbital maintenance. Kimbrough and Whitson explored how microgravity affects body shape and impacts suit sizing. Pesquet joined Andrey Borisenko and set up tiny internal satellites known as SPHERES for an upcoming student competition. Cosmonauts Sergey Ryzhikov and Oleg Novitskiy checked Russian life support systems.

    http://blogs.nasa.gov/spacestation/2017/01/04/astronauts-getting-ready-for-friday-spacewalk-2/
    VIRGO
    VIRGO --- ---
    NASA Kepler and K2: Have Qs about hunting for planets around other suns?
    Join the Twitter Q&A on Jan. 5 at 9:00 CT/15:00 UT. Tag Qs with #askKepler.

    VIRGO
    VIRGO --- ---
    https://www.nasa.gov/image-feature/hues-in-a-crater-slope
    Impact craters expose the subsurface materials on the steep slopes of Mars. However, these slopes often experience rockfalls and debris
    avalanches that keep the surface clean of dust, revealing a variety of hues, like in this enhanced-color image from NASA's Mars Reconnaissance
    Orbiter, representing different rock types. The bright reddish material at the top of the crater rim is from a coating of the Martian dust.

    VIRGO
    VIRGO --- ---
    VIRGO: Massive Arecibo Study Subtracts The Galaxy; Reveals A Pristine Universe
    http://www.forbes.com/...recibo-study-subtracts-the-galaxy-reveals-a-pristine-universe/#42def3e31d0d

    There's a big problem with measuring CMB radiation: no matter where we look, there's intervening matter in the way. It's true that the hotter something is, the more energy
    and light it radiates away. The Big Bang's leftover glow is so cold - just 2.725 K, with fluctuations on the scale of 10s or 100s of µK - that even the coldest interstellar
    gas and dust can cause foreground contamination. Even when observed with the Planck satellite, the most advanced, sophisticated mapping tool every constructed for this
    leftover glow, the foreground emissions from the Milky Way are still a terrible source of pollution and noise.

    The smallest-scale features in light of very particular frequencies (between 22 and 90 GHz) are where some of the most intricate information about the pristine Universe lies.
    The overdense regions (which correspond to blue, cold spots in the fancy image of the CMB) will someday grow into galaxies, clusters and even larger structures. But in order
    to understand how this works in our Universe, we need a full-sky map, not merely a map of the sky except where the galactic plane is. The key, and the hard problem, is to
    properly account for the full suite of the galactic foregrounds. After years of work by hundreds of people, we thought we had done it properly. Yet continued observations
    showed that problems remained, and that the galactic subtraction was incomplete.

    In particular, there were two key puzzles that needed to be solved:

    Why are the magnetic field lines of the galaxy aligned with the orientation of neutral hydrogen? (Which is puzzling, because only charged particles, not neutral ones,
    should be aligned with a magnetic field.)

    And why is that neutral hydrogen associated with the polarization of the CMB? (Which is puzzling because the hydrogen is only hundreds of light years away, but the CMB is
    billions of light years away, and they shouldn't affect each other.)

    The answer is, of course, that these can't be the full story. The leftover glow from the Big Bang can't just randomly align with something happening in our own galaxy; there
    has to be something additional in the galaxy responsible for it! And that means, unfortunately, that our previous calculations for what the Universe looked like behind
    the Milky Way was flawed in a very fundamental way.

    Thankfully, a new study by Gerrit Verschuur and Joan Schmelz using the Arecibo radio telescope was able to study the galactic plane in great detail, in an attempt to uncover
    the cause of the radiation. By viewing a number of foreground, galactic sources at a variety of frequencies, they were able to compare what the radio data showed with what
    the theory predicted. Quite clearly, there was a terrible fit, showing that the previously introduced model of the galaxy was missing a component.

    But if you added in a population of free electrons at relatively warm temperatures (100-300 K), everything gets resolved. The magnetic field lines are aligned with galactic
    hydrogen because there are free, charged particles influencing the neutral hydrogen. The neutral hydrogen isn't aligned with the polarization of the CMB; the free electrons
    are aligned with the electromagnetic radiation's polarization, and they in turn interact with neutral hydrogen. And in the graph above, rather than a downward-sloping line,
    there ought to be a straight, horizontal line that the data follows. You will notice the data doesn't follow it perfectly, and that's good! The leftover signal on top of
    that - the up-and-down wiggles - ought to correspond to the actual fluctuations in the CMB: the Big Bang's leftover glow.

    VIRGO
    VIRGO --- ---
    NASA Selects Mission to Study Black Holes, Cosmic X-ray Mysteries
    https://www.nasa.gov/press-release/nasa-selects-mission-to-study-black-holes-cosmic-x-ray-mysteries

    NASA has selected a science mission that will allow astronomers to explore, for the first time, the hidden details of some of the most extreme
    and exotic astronomical objects, such as stellar and supermassive black holes, neutron stars and pulsars.

    Objects such as black holes can heat surrounding gases to more than a million degrees. The high-energy X-ray radiation from this gas can be polarized –
    vibrating in a particular direction. The Imaging X-ray Polarimetry Explorer (IXPE) mission will fly three space telescopes with cameras capable of
    measuring the polarization of these cosmic X-rays, allowing scientists to answer fundamental questions about these turbulent and extreme environments
    where gravitational, electric and magnetic fields are at their limits.

    The mission, slated for launch in 2020, will cost $188 million. This figure includes the cost of the launch vehicle and post-launch operations and data
    analysis. Principal Investigator Martin Weisskopf of NASA’s Marshall Space Flight Center in Huntsville, Alabama, will lead the mission. Ball Aerospace
    in Broomfield, Colorado, will provide the spacecraft and mission integration. The Italian Space Agency will contribute the polarization sensitive X-ray
    detectors, which were developed in Italy.

    VIRGO
    VIRGO --- ---
    USRA | Arecibo Observatory casts new light on cosmic microwave background observed by WMAP and PLANCK spacecraft: Bringing scientists one step closer to understanding the small-scale structure in the cosmic microwave background
    http://www.usra.edu/news/pr/2017/cosmicmicrowave/

    Arecibo Observatory observations of galactic neutral hydrogen structure confirm the discovery of an unexpected contribution to the measurements of the cosmic microwave
    background observed by the WMAP and Planck spacecraft. An accurate understanding of the foreground (galactic) sources of radiation observed by these two spacecraft is
    essential for extracting information about the small-scale structure in the cosmic microwave background believed to be indicative of events in the early universe.

    The new source of radiation in the 22 to 100 GHz range observed by WMAP and Planck appears to be emission from cold electrons (known as free-free emission). While
    cosmologists have corrected for this type of radiation from hot electrons associated with galactic nebulae where the source temperatures are thousands of degrees,
    the new model requires electron temperatures more like a few 100 K.

    The spectrum of the small-scale features observed by WMAP and Planck in this frequency range is very nearly flat - a finding consistent with the sources being associated
    with the Big Bang. At first glance it appears that the spectrum expected from the emission by cold galactic electrons, which exist throughout interstellar space, would
    be far too steep to fit the data. However, if the sources of emission have a small angular size compared with the beam width used in the WMAP and Planck spacecraft, the
    signals they record would be diluted. The beam widths increase with lower frequency, and the net result of this "beam dilution" is to produce an apparently flat spectrum
    in the 22 to 100 GHz range.

    The model invoking the emission from cold electrons not only gives the observed flat spectrum usually attributed to cosmic sources but also predicts values for the angular
    scale and temperature for the emitting volumes. Those predictions can then be compared with observations of galactic structure revealed in the Galactic Arecibo L-Band Feed
    Array (GALFA) HI survey.

    "The interstellar medium is much more surprising and important than we have given it credit for," noted Dr. Joshua Peek, an astronomer at the Space Telescope Science
    Institute and a co-investigator on the GALFA-HI survey. "Arecibo, with its combination of large area and high resolution, remains a spectacular and cutting edge tool
    for comparing ISM maps to cosmological data sets."

    The angular scales of the smallest features observed in neutral hydrogen maps made at Arecibo and the temperature of the apparently associated gas both match the model
    calculations extremely well. So far only three well-studied areas have been analyzed in such detail, but more work is being planned.

    "It was the agreement between the model predictions and the GALFA-HI observations that convinced me that we might be onto something," noted Dr. Joan Schmelz, Director,
    Universities Space Research Association (USRA) at Arecibo Observatory and a coauthor on the paper. "We hope that these results help us understand the true cosmological
    nature of Planck and WMAP data."

    The data suggest that the structure and physics of diffuse interstellar matter, in particular of cold hydrogen gas and associated electrons, may be more complex than
    heretofore considered. Such complexities need to be taken into account in order to produce better foreground masks for application to the high-frequency continuum
    observations of Planck and WMAP in the quest for a cosmologically significant signal.

    VIRGO
    VIRGO --- ---
    Working at Subaru Telescope 3. Instrumentation & Electronics
    https://www.youtube.com/watch?v=shCMkZI9LuQ
    VIRGO
    VIRGO --- ---
    USRA | A venerable radio telescope sets new standard for universal constant
    http://www.usra.edu/news/pr/2017/fundamentalconstant/

    About 150 hours of observing time on the 1,000-ft radio telescope at the Arecibo Observatory in Puerto Rico over the course of the last several years have been devoted
    to determining whether the most fundamental constant in physics really is constant.

    The target is the so-called fine structure constant, usually known as alpha, which describes the electromagnetic interaction between elementary charged particles. Its
    value is crucial to understanding the nature of atomic spectra, which in turn allows astronomers to measure the radial velocity of galaxies from which these spectral
    lines are observed. Such observations led to the discovery that galaxies appear to be receding from one another with velocities that increase with the distance between
    them. This is a manifestation of the expansion of the universe following the Big Bang.

    Our current model for the expansion and acceleration of the universe depends on the assumption that neither alpha nor mu, the proton-to-electron mass ratio, have changed
    with time. This assumption is key to our current understanding of the age of the universe. But what if alpha does change with time? Then our knowledge of the distance
    between galaxies or the age of the universe would have to be revised.

    The Arecibo telescope has recently been used to set a new limit on how constant things are. While the latest data suggest that there may be a small change in alpha,
    it is still too early to be sure. With an uncertainty on the measurement of about one part in a million, it is not yet time to celebrate, nor to heave a sigh of relief.

    The Arecibo observations have been carried out by Nissim Kanekar and Jayaram Chengalur of the National Center for Radio Astrophysics in India, and Tapasi Ghosh,
    a Universities Space Research Association (USRA) astronomer at the Arecibo Observatory. Their experiment makes use of a marvelous concordance of cosmic circumstances
    involving quasar PKS 1413+135, which is located about 3 billion light-years away. In front of that quasar, and probably surrounding its radio-bright nucleus, is a cloud
    of OH molecules (OH is also known as hydroxyl).

    The atomic properties of hydroxyl are extremely well known from laboratory and theoretical studies. The OH cloud in the Arecibo experiment is observed in two spectral lines,
    one at 1612 MHz and the other at 1720 MHz. What is unusual is that one of the lines (1612) is seen in absorption and the other (1720) in emission. These lines are said to be
    conjugate, that is, they are mirror images of one another, which assures that they originate from the same gas cloud.

    This is a crucial factor in reducing systematic uncertainties in the measurement of alpha. From the Arecibo spectra, we can measure the observed frequency difference between
    the two lines and compare that with the laboratory results. Because this quasar is seen as it was 3 billion years in the past and our laboratory is in the present,
    we can determine just how truly constant alpha is over time.

    The 150-hour integration at Arecibo allows the two spectral lines to be compared with very high accuracy.
    The result implies that alpha has not changed by more than 1.3 parts in a million, in these 3 billion years.
    VIRGO
    VIRGO --- ---
    USRA | Arecibo Observatory Radio Data Crucial to Understanding why Quasars are so Bright
    http://www.usra.edu/news/pr/2017/quasars/

    Remarkable new observations derived by linking Arecibo Observatory's 305-meter dish with the Russian RadioAstron space radio telescope have provided results
    that are causing much head scratching in radio astronomical circles. What used to be a well-understood explanation of the mechanism that generates intense
    radio signals from tiny and very distant quasar nuclei has now been tested in previously impossible ways.

    The RadioAstron satellite, launched in 2011 by the Russian Federal Space Agency, carries a 10-m radio dish and is traveling around the Earth in a highly elliptical
    orbit that takes it out to 350,000 km from Earth -- almost the distance to the Moon. When the signals it receives from a distant quasar are combined with simultaneous
    data acquired by its Earth-based partners at Arecibo in Puerto Rico, Green Bank in West Virginia, Socorro in New Mexico, and Bonn in Germany, the observations simulate
    a dish up to 350,000 km in diameter. This network of telescopes operates at frequencies (wavelengths) of 330 MHz (92 cm), 1.7 GHz (18 cm), 4.7 GHz (6.2 cm) and 22 GHz
    (1.3 cm).

    Combining the signals produces what are called fringes, and it was recently reported that quasar 3C 273 was detected at a baseline of 170,000 km (106,000 miles).
    This remarkable achievement showed that 3C 273 has structure in its core at least as small as 26 microarcseconds across. At the distance of 3C 273, this corresponds
    to a physical diameter of 2.7 light-months. The ability to see such detail is not matched by any other telescope in the world. Optical telescopes, even the Hubble
    Space Telescope, do not come anywhere near this ability to see detailed structure.

    So far RadioAstron and its terrestrial partners have not detected details smaller than the 26 microarcseconds in 3C 273's core, but already the observations are
    pushing the theory of radio source emission mechanisms beyond their limit.

    Radio astronomers measure the apparent brightness of objects such as quasars in terms of the temperature a solid body subtending the same angular size would have to
    possess in order to shine with the same intensity. The smaller the angular diameter of the object producing the radio signals, the higher its source temperature must
    be to produce the observed signal.

    The 3C 273 data reveal that its brightness temperature must be about 4 x 10^13 K, that is, a 4 followed by 13 zeroes, or 40 trillion degrees. The problem is that
    the maximum allowed by present theories for radio emission from a quasar is about 10^12 K, which is to say around one trillion degrees Celsius.

    "Temperatures this high test our understanding of the physics in the vicinity of supermassive black hole at the heart of 3C 273," noted Dr. Tapasi Ghosh, the VLBI
    staff astronomer at Arecibo Observatory. "We hope that Arecibo-RadioAstron observations of other sources will help shed light on this mystery."

    VIRGO
    VIRGO --- ---
    USRA | The Mystery of Part-Time Pulsars
    http://www.usra.edu/news/pr/2017/pulsar/

    A new discovery has upended the widely held view that all pulsars are orderly ticking clocks of the universe.
    A survey done at the Arecibo Observatory in Puerto Rico has fortuitously discovered two extremely strange pulsars
    that undergo a "cosmic vanishing act." Sometimes they are there, and then for very long periods of time, they are not.

    Recognizing the existence of this strange behavior was fortuitous in itself. It took great patience on the part of
    a team of radio astronomers at Jodrell Bank in the UK led by Professor Andrew Lyne of the University of Manchester
    to confirm the existence of these mostly invisible pulsars.

    Intermittent pulsars are a rarely observed population of pulsars, which have two states -- one when they pulse like
    normal pulsars (the ON state), and another when they mysteriously fail to work, producing no radio waves at all (the
    OFF state). "They switch instantaneously between the states," notes Lyne. "They're ON and then they're gone,
    disappearing without any apparent warning."

    A 34-member pulsar study team, including Dr. Andrew Seymour, a USRA postdoc at Arecibo, used the 7-beam receiver to
    conduct routine pulsar searches in what they call the PALFA (Pulsar Arecibo L-Band Feed Array) Survey. The two recently
    discovered intermittent pulsars spend most of their time in the OFF state. Three other similar pulsars are also known,
    but they are mostly ON.

    VIRGO
    VIRGO --- ---
    Už to jede, už to sviští - jako bába na kluzišti! ARECIBO prezentace, uf, nestíhám sledovat!
    Snad tohle také pomůže observatoři přežít! Na AAS mají hned několik anoncí najednou. Jdu na to. :)
    VIRGO
    VIRGO --- ---
    Psyche : A Metal Asteroid, Core of Destroyed Planet
    https://www.youtube.com/watch?v=cs150BwRp5c
    XCHAOS
    XCHAOS --- ---
    Osobně jsem už nějaký čas pošilhával po misi k Psýché - už proto, že nějaké ty kovové patvary v kráterech určitě budou stát za to... (i když kov může být schován pod nánosem bordelu, jako voda na Ceres..)
    VIRGO
    VIRGO --- ---
    The SwRI Lucy mission will fly to a number of Trojan asteroids, including the Patroclus-Menoetius system, a nearly equal-sized binary.

    VIRGO
    VIRGO --- ---
    JULIANNE: Já jsem ve fanklubu Psyche, takže dnes bouchne šampáňo, co jsem neotevřel na Silvestra.. :)
    NEBULA
    NEBULA --- ---
    VIRGO: no já se právě vylekala (pozitivně), že se chystá nějaký great oznámení, co se toho týče... :) no takže takhle taky dobrý :)
    JULIANNE
    JULIANNE --- ---
    VIRGO: Trochu jsem doufala v DAVINCI a/nebo VERITAS, ale tenhle výsledek mi vůbec nevadí, Lucy i Psyche bych také hrozně ráda viděla zafinancované a vypuštěné za záhadami vesmíru! Na rozdíl od misí k Venuši to bude něco úplně nového, tak už se hrozně těším a je úžasné, že skutečně vybrali dvě mise - ale kéž by se tak našly prostředky pro čtyři :-). Nebo pět, kdyby i NEOCam... (Ale to je sci-fi, tak si to člověk bude muset napsat :).)
    VIRGO
    VIRGO --- ---
    NEBULA: No jako každoročně! :) Dnes začala jedna z těch nej konferencí!!
    229th Meeting of the American Astronomical Society | American Astronomical Society
    https://aas.org/meetings/aas229
    To znamená každodenní úžasná oznámení a zprávy, bohužel pro mně zároveň rapidní pokles
    pracovní výkonnosti a odespaných hodin za noc (přes vánoce probíhá příprava...:D)

    Pokud se ptáš na toto konkrétní oznámení, tak to je celkem prda na začátek, protože tuhle FRB
    "záhadu" řeší astr-nomové/-fyzici cca od půlky minulé dekády. Doposud totiž netušíme, co že je
    vlastně způsobuje, takže alespoň je ztotožnit s místem a typem objektu, kde vznikají, je hodně
    slibné, že se podaří je objasnit (FRB - velmi rychlé a prudké záblesky tvrdého gama záření, ale
    mnohdy táhnoucí se více obory EM záření. Trvají v řádek milisekund, ale uvolňují se při nich energie
    desítek/stovek sluncí. Celkem bizár...)
    NEBULA
    NEBULA --- ---
    VIRGO: to je nádhera, i ta andromeda níže! krása prostě :)

    VIRGO:
    VIRGO: co to co to co to??
    Kliknutím sem můžete změnit nastavení reklam