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 Post subject: Cosmology Thread
PostPosted: Thu Sep 08, 2016 6:50 pm 
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Everything about our universe related to structure, constants, and yawning voids of cosmic horror.

It’s official: You’re lost in a directionless universe

http://www.sciencemag.org/news/2016/09/ ... s-universe

Quote:
(O)ne team of cosmologists has used the oldest radiation there is, the afterglow of the big bang, or the cosmic microwave background (CMB), to show that the universe is “isotropic,” or the same no matter which way you look: There is no spin axis or any other special direction in space. In fact, they estimate that there is only a one-in-121,000 chance of a preferred direction—the best evidence yet for an isotropic universe.


Which might harken to Lovecraft's epigraph from his prose poem Nyarlathotep

Quote:
I have seen the dark universe yawning, Where the black planets roll without aim; Where they roll in their horror unheeded, without knowledge or lustre or name.

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 Post subject: Re: Cosmology Thread
PostPosted: Fri Sep 09, 2016 10:30 am 
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Astronomers have created the most detailed 'age map' of the Milky Way yet

http://www.sciencealert.com/astronomers ... ky-way-yet

Quote:
"...now we have demonstrated conclusively for the first time that ancient stars are in the centre of the galaxy and the younger stars are found at longer distances. This is another piece of information that we can use to understand the assembly process of the galaxy, and how galaxies in general formed.

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 Post subject: Re: Cosmology Thread
PostPosted: Wed Sep 14, 2016 6:20 am 
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Gaia's first annotated sky map

http://www.esa.int/spaceinimages/Images ... _annotated

Direct link to image: https://www.esa.int/var/esa/storage/ima ... otated.png

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 Post subject: Re: Cosmology Thread
PostPosted: Wed Sep 14, 2016 1:59 pm 
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Not sure why this would necessarily be in the Cosmology section, but a "pretty picture" is not the point of Gaia -- the data is. The only function of the map is to show the density of Gaia data collection (so far) as described in the text accompanying the picture. In fact, as they note, there are a number on artifacts in the current picture that will diminish as more data is collected.

Here's a quote from Brian Skiff (Lowell Observatory) posted on the Amastro group today:

Quote:
For those who care about stars, as of today, the
GAIA DR1 catalogue is now searchable at VizieR. It is
described here:

http://cdsarc.u-strasbg.fr/viz-bin/Cat?I/337

There are a billion entries with just coordinates and
a (very) broadband magnitude, but for the 2.5 million
stars in common with Tycho-2 there are proper motions
and parallaxes.

I haven't started to look in detail, but that'll
probably be a long process.

\Brian


It's not light reading!

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 Post subject: Re: Cosmology Thread
PostPosted: Wed Sep 14, 2016 2:35 pm 
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And of course, Sky & Telescope has an online Gaia article with a nice overview...

http://www.skyandtelescope.com/astronom ... ion-stars/

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 Post subject: Re: Cosmology Thread
PostPosted: Sun Sep 18, 2016 10:38 am 
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If Dark Matter Can't Be Seen, What About Ghosts?

http://www.npr.org/sections/13.7/2016/0 ... out-ghosts

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 Post subject: Re: Cosmology Thread
PostPosted: Mon Sep 19, 2016 6:37 pm 
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Phil Plait weighs in on the biggest galaxy in the universe.

http://www.slate.com/blogs/bad_astronom ... verse.html

Of course it would be the biggest known galaxy in the universe since there's probably something even bigger we haven't seen yet.

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 Post subject: Re: Cosmology Thread
PostPosted: Wed Oct 05, 2016 8:05 am 
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Blinded by the Dark (Energy)

http://www.scientificamerican.com/artic ... rk-energy/

Quote:
The question is why the vacuum of space should have energy at all. Quantum-field theory posits a profusion of virtual particles that briefly come into existence and then disappear—a seemingly outrageous idea, but one that has allowed quantum theorists to make extremely accurate predictions of how ordinary particles interact. These virtual particles could be behind dark energy's repulsive force.

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 Post subject: Re: Cosmology Thread
PostPosted: Thu Oct 06, 2016 7:18 am 
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In the Dark about Dark Matter

https://www.scientificamerican.com/arti ... rk-matter/

Quote:
Theorists have two intertwined reasons to hunt for WIMPs. The first is that WIMPs are a natural consequence of the most popular extensions to the Standard Model of particle physics, which predicts their production shortly after the big bang. The second is that if such primordial WIMPs exist, straightforward calculations suggest their present-day abundance and behavior should now almost exactly match the quantities and qualities of dark matter inferred from observations. This so-called WIMP miracle has sustained the search for decades, but now some theorists are questioning its validity.

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 Post subject: Re: Cosmology Thread
PostPosted: Wed Oct 12, 2016 6:12 am 
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Big Bang, Deflated? Universe may have had no beginning at all!

http://www.physics-astronomy.com/2015/0 ... e-had.html

Apparently it's all about dark matter and "quantum" stuff.

EarthSky gives a little hope for this cosmological chestnut.

http://earthsky.org/space/what-if-the-u ... -beginning

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 Post subject: Re: Cosmology Thread
PostPosted: Wed Oct 12, 2016 9:37 am 
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What Happened to the Universe's Primordial Hydrogen?

http://www.livescience.com/56442-what-h ... rogen.html

Quote:
However, when our universe was about one billion years old, it appears that nine out of every 10 of those original hydrogen atoms were destroyed before they ever found their way into galaxies. Exactly when and how were those first atoms in the universe destroyed? Astronomers have puzzled over these questions for decades. I'm leading a new experiment – known as the Hydrogen Epoch of Reionization Array (HERA) – that we hope will help answer what happened.

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 Post subject: Re: Cosmology Thread
PostPosted: Thu Oct 13, 2016 8:25 am 
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The strongest evidence of the big bang was almost mistaken for pigeon droppings

http://www.sciencealert.com/the-stronge ... -droppings

The video at Aeon is a bit more entertaining and informative.

https://aeon.co/videos/how-pigeon-dropp ... -cosmology

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 Post subject: Re: Cosmology Thread
PostPosted: Fri Oct 14, 2016 7:45 am 
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Astronomers may now fully understand why the sky is dark at night

https://amp.businessinsider.com/hubble- ... se-2016-10

Quote:
(T)he authors suggest that distant and red-shifted (though otherwise visible) galaxies could have their light absorbed by gas and dust in the void of space, then re-emitted in infrared and ultraviolet wavelengths that are invisible to human eyes.


Terrible article layout. Is it necessary to have desktop wallpaper-sized images every five lines?

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 Post subject: Re: Cosmology Thread
PostPosted: Sat Oct 15, 2016 8:00 am 
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Universe is far bigger and more stuffed with galaxies than previously thought

http://www.independent.co.uk/life-style ... 60736.html

Quote:
It was previously thought that the observable universe had about 100 billion galaxies – until the new study found far more.


Trillions and trillions.

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 Post subject: Re: Cosmology Thread
PostPosted: Sat Oct 15, 2016 8:00 am 
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Gravitational Waves May Permanently Alter Spacetime

http://www.pbs.org/wgbh/nova/next/physi ... ve-memory/

Quote:
To understand what gravitational-wave memory entails, imagine a binary system in outer space consisting of two black holes. There are two astronauts drifting side by side in orbit around this black hole binary, who “are initially separated from one another by some distance, 10 meters say,” Lasky says. As the black holes spiral towards one another, they will release gravitational waves that will travel at the speed of light and cause the distance between the astronauts and the black holes to fluctuate, and they will also cause the distance between the astronauts to oscillate between a little more and a little less than 10 meters. Once the black holes have collided and merged into a single black hole, these oscillations will stop, and the astronauts will once again be separated by a constant distance. However, “this constant distance is not the original 10 meters, but will be slightly more or slightly less,” Lasky says. The gravitational waves will have permanently stretched or squeezed the fabric of spacetime.

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 Post subject: Re: Cosmology Thread
PostPosted: Sat Oct 15, 2016 4:02 pm 
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About Those 2 Trillion New Galaxies . . .

http://www.skyandtelescope.com/astronom ... -galaxies/

Quote:
Maybe you saw today's news that the universe contains "10 times as many galaxies as astronomers previously thought." Well, there's 10 times less to that announcement than meets the eye. But the real news is interesting enough.

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 Post subject: Re: Cosmology Thread
PostPosted: Sat Oct 15, 2016 4:05 pm 
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Scientists claim to have discover what existed before the beginning of the universe

http://www.physics-astronomy.com/2016/1 ... -what.html

Quote:
In our cosmological model the universe did not start with the big bang, but there was a phase transition from one phase of the universe to another.


Quote pulled from Non-singular and Cyclic Universe from the Modified GUP at arXiv

https://arxiv.org/abs/1608.00560

Of course long-time Marvel fans know Galactus is the sole survivor from the civilization destroyed by the Big Bang.

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 Post subject: Re: Cosmology Thread
PostPosted: Mon Oct 17, 2016 3:54 pm 
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Not exactly cosmology but close enough.

Do Stars Within A Galaxy Touch One Another?

http://www.forbes.com/sites/jillianscud ... -touching/

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 Post subject: Re: Cosmology Thread
PostPosted: Fri Oct 21, 2016 10:51 am 
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The universe is expanding at an accelerating rate—or is it?

http://phys.org/news/2016-10-universe-rateor.html

Quote:
Now, a team of scientists led by Professor Subir Sarkar of Oxford University's Department of Physics has cast doubt on this standard cosmological concept. Making use of a vastly increased data set - a catalogue of 740 Type Ia supernovae, more than ten times the original sample size - the researchers have found that the evidence for acceleration may be flimsier than previously thought, with the data being consistent with a constant rate of expansion.

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 Post subject: Re: Cosmology Thread
PostPosted: Fri Oct 21, 2016 11:14 am 
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Monstrous cloud of hydrogen and sulfur is on a collision course with the Milky Way

http://www.physics-astronomy.com/2016/1 ... ulfur.html

It's like the galaxy's biggest fart!

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 Post subject: Re: Cosmology Thread
PostPosted: Wed Oct 26, 2016 10:01 am 
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Dark energy may not exist, new supernova analysis says

https://cosmosmagazine.com/physics/dark ... lysis-says

They're recapitulating a previous link in this thread about the universe's expansion not accelerating, as previously believed, but it has an impact on the theory of dark energy.

IMO dark energy and dark matter will be the luminiferous aether of the 22nd century.

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 Post subject: Re: Cosmology Thread
PostPosted: Thu Oct 27, 2016 7:13 am 
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This Is Our Amazing Technicolor Cosmos

http://www.seeker.com/this-is-our-amazi ... 21689.html

Quote:
As seen with a radio telescope in the West Australian outback, the our universe resembles a psychedelic piece of pop art.

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 Post subject: Re: Cosmology Thread
PostPosted: Mon Nov 14, 2016 7:01 pm 
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New theory of gravity might explain dark matter

http://phys.org/news/2016-11-theory-gravity-dark.html

Quote:
According to Erik Verlinde, there is no need to add a mysterious dark matter particle to the theory. In a new paper, which appeared today on the ArXiv preprint server, Verlinde shows how his theory of gravity accurately predicts the velocities by which the stars rotate around the center of the Milky Way, as well as the motion of stars inside other galaxies.

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 Post subject: Re: Cosmology Thread
PostPosted: Wed Nov 16, 2016 7:04 am 
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High-speed electrons have been spotted outside Earth's magnetic field, and NASA can't explain it

http://www.sciencealert.com/particles-a ... explain-it

Almost to the speed of light...

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 Post subject: Re: Cosmology Thread
PostPosted: Wed Nov 16, 2016 10:13 am 
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Twisters Pop Up in Weird 'Big Bang' Soup

http://www.livescience.com/56888-twiste ... -soup.html

Quote:
Recently, when simulating the quark-gluon plasma using a supercomputer, researchers found that the "soup" produced structures shaped like rings and vortices. Moreover, the viscosityof the fluid — its resistance to deforming — in the simulations was nearly as low as it could be and still followed the laws of quantum mechanics, the branch of physics that deals with extremely small particles. The simulated plasma was a superfluid, or a fluid with nearly zero friction, the researchers said.

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