Archive for the ‘cosmology’ category: Page 4

Oct 25, 2020

How the world came to understand black holes

Posted by in categories: cosmology, physics

Earlier this month, Roger Penrose, Reinhard Genzel, and Andrea Ghez split the 2020 physics Nobel Prize for decades of work on black holes. Click here to learn more about their monumental achievement and about the history of our understanding of these exotic objects in space.

Oct 24, 2020

Precision metrology closes in on dark matter

Posted by in categories: cosmology, particle physics

Optical clocks are so accurate that it would take an estimated 20 billion years—longer than the age of the universe—to lose or gain a second. Now, researchers in the U.S. led by Jun Ye’s group at the National Institute of Standards and Technology and the University of Colorado have exploited the precision and accuracy of their optical clock and the unprecedented stability of their crystalline silicon optical cavity to tighten the constraints on any possible coupling between particles and fields in the standard model of physics and the so-far elusive components of dark matter.

The existence of dark matter is indirectly evident from gravitational effects at galactic and cosmological scales, but beyond that, little is known of its nature. One of the effects that falls out of theoretical analysis of dark matter coupling to particles in the standard model of physics is a resulting oscillation in . Ye and collaborators figured that if their world-class metrology equipment could not detect these oscillations, then this apparently null result would be useful confirmation that the strength of dark matter interactions with particles in the standard model of physics must be even lower than dictated by the constraints so far on record.

Oct 23, 2020

New theory on the origin of dark matter

Posted by in category: cosmology

A recent study from the University of Melbourne proposes a new theory for the origin of dark matter, helping experimentalists in Australia and abroad in the search for the mysterious new matter.

The work has been published in Physical Review Letters and describes how expanding bubbles in the early universe may be the key to understanding dark matter.

“Our proposed mechanism suggests that the dark matter abundance may have been determined in a cosmological phase transition,” said Dr. Michael Baker, a postdoctoral research fellow at the University of Melbourne and one of the authors.

Oct 22, 2020

Why are galaxies different shapes?

Posted by in category: cosmology

Look into the night sky and you’ll glimpse the stars from hundreds of billions of galaxies. Some galaxies are swirling blue disks like our own Milky Way, others are red spheres or misshapen, clumpy messes or something in between. Why the different configurations? It turns out that a galaxy’s shape tells us something about the events in that galaxy’s ultra-long life.

At the very basic level there are two classifications for galaxy shapes: disk and elliptical. A disk galaxy, also called a spiral galaxy, is shaped like a fried egg, said Cameron Hummels, theoretical astrophysicist at Caltech. These galaxies have a more spherical center, like the yolk, surrounded by a disk of gas and stars — the egg white. The Milky Way and our nearest galaxy neighbor Andromeda fall into this category.

Oct 21, 2020

RHIC Collider Creates Quark-Gluon Plasma at 4,000,000,000,000 Degrees Celsius

Posted by in categories: cosmology, particle physics

Circa 2010

Until the LHC finally gets up to full speed, Brookhaven National Lab’s Relativistic Heavy Ion Collider (RHIC) remains the world’s most powerful heavy ion smasher. And on Monday, they showed off some of that power by announcing that a recent collision resulted in the hottest matter ever recorded. Coming in at a scorching 7.2 trillion degrees Fahrenheit, the plasma not only recreated the environment of the Big Bang, but might have also resulted in the temporary formation of a bubble within which some normal laws of physics did not apply.

Continue reading “RHIC Collider Creates Quark-Gluon Plasma at 4,000,000,000,000 Degrees Celsius” »

Oct 20, 2020

The 2020 Nobel Prize in physics awarded for work on black holes. An astrophysicist explains the trailblazing discoveries

Posted by in categories: cosmology, mathematics, physics, singularity

Black holes are perhaps the most mysterious objects in nature. They warp space and time in extreme ways and contain a mathematical impossibility, a singularity – an infinitely hot and dense object within. But if black holes exist and are truly black, how exactly would we ever be able to make an observation?

This morning the Nobel Committee announced that the 2020 Nobel Prize in physics will be awarded to three scientists – Sir Roger Penrose, Reinhard Genzel and Andrea Ghez – who helped discover the answers to such profound questions. Andrea Ghez is only the fourth woman to win the Nobel Prize in physics.

Continue reading “The 2020 Nobel Prize in physics awarded for work on black holes. An astrophysicist explains the trailblazing discoveries” »

Oct 18, 2020

‘Spider’s web’ traps six galaxies around supermassive black hole

Posted by in category: cosmology

Scientists have spotted six galaxies that appear trapped in orbit around a supermassive black hole that astronomers are seeing as it was when the universe was less than a billion years old.

Oct 18, 2020

Nobel Prize in Physics Winner

Posted by in categories: biotech/medical, cosmology, physics

It’s unbelievable all that’s going on at the moment in astronomy” — DER SPIEGEL — international.

DER SPIEGEL: Wherever black holes are discussed, that picture is shown. And you are now telling us that we don’t really even know what it is?

Genzel: Exactly. It could be that we are looking at the shadow of a black hole, as it is commonly portrayed. But it could also be the outer wall of a jet that is coming directly at us at the speed of light. To know for sure, we need additional measurements. But we have a problem at the moment: the corona pandemic. Most Earth-based telescopes have been switched off.

Continue reading “Nobel Prize in Physics Winner” »

Oct 18, 2020

How Close Are We to Finding Dark Matter?

Posted by in category: cosmology

95% of our universe is missing.

Oct 16, 2020

Apparent evidence for Hawking points in the CMB Sky ★

Posted by in category: cosmology

ABSTRACT. This paper presents strong observational evidence of numerous previously unobserved anomalous circular spots, of significantly raised temperature, in the cosmic microwave background sky. The spots have angular radii between 0.03 and 0.04 rad (i.e. angular diameters between about 3° and 4°). There is a clear cut-off at that size, indicating that each anomalous spot would have originated from a highly energetic point-like source, located at the end of inflation – or else point-like at the conformally expanded Big Bang, if it is considered that there was no inflationary phase. The significant presence of these anomalous spots, was initially noticed in the Planck 70 GHz satellite data by comparison with 1000 standard simulations, and then confirmed by extending the comparison to 10 000 simulations. Such anomalous points were then found at precisely the same locations in the WMAP (Wilkinson Microwave Anisotropy Probe) data, their significance was confirmed by comparison with 1000 WMAP simulations. Planck and WMAP have very different noise properties and it seems exceedingly unlikely that the observed presence of anomalous points in the same directions on both maps may come entirely from the noise. Subsequently, further confirmation was found in the Planck data by comparison with 1000 FFP8.1 MC simulations (with l ≤ 1500). The existence of such anomalous regions, resulting from point-like sources at the conformally stretched-out big bang, is a predicted consequence of conformal cyclic cosmology, these sources being the Hawking points of the theory, resulting from the Hawking radiation from supermassive black holes in a cosmic aeon prior to our own.

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