Cosmos In Brief - Aktualní novinky vesmírného výzkumu v kostce

VIRGO --- --- 15:43:06 8.1.2018

Gravitational Waves Measure the Universesu201801 | www.cfa.harvard.edu/
https://www.cfa.harvard.edu/news/su201801

The direct detection of gravitational waves from at least five sources during the past two years offers spectacular confirmation of Einstein's model of gravity and space-time. Modeling of these events has also
provided information on massive star formation, gamma-ray bursts, neutron star characteristics, and (for the first time) verification of theoretical ideas about how the very heavy elements, like gold, are produced.

Astronomers have now used a single gravitational wave event (GW170817) to measure the age of the universe. CfA astronomers Peter Blanchard, Tarreneh Eftekhari, Victoria Villar, and Peter Williams were members
of a team of 1314 scientists from around the world who contributed to the detection of gravitational waves from a merging pair of binary neutron stars, followed by the detection of gamma-rays, and then the
identification of the origin of the cataclysm in a source in the galaxy NGC4993 spotted in images taken with various time delays at wavelengths from the X-ray to the radio.

An analysis of the gravitational waves from this event infers their intrinsic strength. The observed strength is less, implying (because the strength diminishes with distance from the source) that the source
is about 140 million light-years away. NGC4993, its host galaxy, has an outward velocity due to the expansion of the universe that can be measured from its spectral lines. Knowing how far away it is and how fast
the galaxy is moving from us allows scientists to calculate the time since the expansion began – the age of the universe: between about 11.9 and 15.7 billion years given the experimental uncertainties.

VIRGO --- --- 15:41:28 8.1.2018

Plot thickens as New Horizons moves within year of next flyby – Astronomy Now
https://astronomynow.com/2018/01/06/plot-thickens-as-new-horizons-moves-within-year-of-next-flyby/

The final days before NASA’s New Horizons probe barrels in on its next destination on Jan. 1, 2019, should prove eventful, with scientists trying
to sort out whether a distant mini-world detected by the Hubble Space Telescope more than three years ago may actually be a swarm of icy objects.

New Horizons’ sharp-eyed camera will serve as a look-out as the spacecraft makes a speedy approach toward 2014 MU69, the official name for the mission’s
next target. Scientists will search for moons and icy debris, discoveries which could add intrigue to the one-shot encounter on New Year’s Day 2019.

BLACKHEAD --- --- 17:57:22 5.1.2018

VIRGO: To vypada (podle tech ryh) jako kus zkameneleho bahna...

VIRGO --- --- 16:56:12 5.1.2018

1 odpověď +3

Krásný kousek!

NASA rover spots strange 'stick-like figures' on Mars - CNET
https://www.cnet.com/au/news/nasa-mars-rover-curiosity-stick-like-figures-crystals/

While the rest of us were on vacation over the holidays, the Mars Curiosity rover kept plugging away at its mission of exploring the Red Planet. It put some of the time
into inspecting and photographing a set of fascinating stick-like formations on the Martian ground. The rover team tweeted a good look at the small objects on Wednesday.

VIRGO --- --- 16:32:20 5.1.2018

https://www.nasa.gov/image-feature/jpl/pia21973/high-above-jupiter-s-clouds

NASA’s Juno spacecraft was a little more than one Earth diameter from Jupiter when it captured this mind-bending, color-enhanced view of the planet’s tumultuous atmosphere.

Jupiter completely fills the image, with only a hint of the terminator (where daylight fades to night) in the upper right corner, and no visible limb (the curved edge of the planet).

Juno took this image of colorful, turbulent clouds in Jupiter’s northern hemisphere on Dec. 16, 2017 at 9:43 a.m. PST (12:43 p.m. EST) from 8,292 miles (13,345 kilometers) above
the tops of Jupiter’s clouds, at a latitude of 48.9 degrees. The spatial scale in this image is 5.8 miles/pixel (9.3 kilometers/pixel).

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

VIRGO --- --- 16:30:29 5.1.2018

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 --- --- 16:29:34 5.1.2018

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 --- --- 18:01:39 4.1.2018

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 --- --- 15:05:07 4.1.2018

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 --- --- 14:43:24 4.1.2018

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 --- --- 17:43:24 3.1.2018

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 --- --- 17:30:46 3.1.2018

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 --- --- 0:12:34 3.1.2018

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 --- --- 17:30:09 29.12.2017

The Plasma Magnet Drive: A Simple, Cheap Drive for the Solar System and Beyond
https://www.centauri-dreams.org/?p=39048

JAYME --- --- 18:46:01 22.12.2017

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 --- --- 18:31:51 22.12.2017

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 --- --- 17:30:18 22.12.2017

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 --- --- 16:08:03 22.12.2017

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 --- --- 14:43:19 22.12.2017

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 --- --- 14:41:25 22.12.2017

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.

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