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(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.

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.

"...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.

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

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.

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.

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.

(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.

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

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.

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.

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.

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.

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

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.

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.