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Archive for the ‘cosmology’ category

Jan 15, 2020

Precise measurements find a crack in universal physics

Posted by in categories: chemistry, cosmology, particle physics, quantum physics

The concept of universal physics is intriguing, as it enables researchers to relate physical phenomena in a variety of systems, irrespective of their varying characteristics and complexities. Ultracold atomic systems are often perceived as ideal platforms for exploring universal physics, owing to the precise control of experimental parameters (such as the interaction strength, temperature, density, quantum states, dimensionality, and the trapping potential) that might be harder to tune in more conventional systems. In fact, ultracold atomic systems have been used to better understand a myriad of complex physical behavior, including those topics in cosmology, particle, nuclear, molecular physics, and most notably, in condensed matter physics, where the complexities of many-body quantum phenomena are more difficult to investigate using more traditional approaches.

Understanding the applicability and the robustness of universal is thus of great interest. Researchers at the National Institute of Standards and Technology (NIST) and the University of Colorado Boulder have carried out a study, recently featured in Physical Review Letters, aimed at testing the limits to universality in an ultracold system.

“Unlike in other physical systems, the beauty of ultracold systems is that at times we are able to scrap the importance of the periodic table and demonstrate the similar phenomenon with any chosen atomic species (be it potassium, rubidium, lithium, strontium, etc.),” Roman Chapurin, one of the researchers who carried out the study, told Phys.org. “Universal behavior is independent of the microscopic details. Understanding the limitations of universal phenomenon is of great interest.”

Jan 15, 2020

Astronomers discover class of strange objects near our galaxy’s enormous black hole

Posted by in category: cosmology

Astronomers from UCLA’s Galactic Center Orbits Initiative have discovered a new class of bizarre objects at the center of our galaxy, not far from the supermassive black hole called Sagittarius A*. They published their research today in the journal Nature.

“These objects look like gas and behave like ,” said co-author Andrea Ghez, UCLA’s Lauren B. Leichtman and Arthur E. Levine Professor of Astrophysics and director of the UCLA Galactic Center Group.

The new objects look compact most of the time and stretch out when their orbits bring them closest to the black hole. Their orbits range from about 100 to 1,000 years, said lead author Anna Ciurlo, a UCLA postdoctoral researcher.

Jan 15, 2020

‘Giant, shape-shifting stars’ spotted near Milky Way’s black hole

Posted by in category: cosmology

Objects raise hopes of scientists managing to track ‘blobs’ being swallowed by black hole.

Jan 12, 2020

Scientists detected ripples in space and time from a potentially new class of collision in the universe. Their observatory cracked a 100-year-old mystery posed by Einstein

Posted by in category: cosmology

The collision might have produced hundreds of Earths’ worth of gold and platinum. But some signs indicate the metals disappeared into a black hole.

Jan 11, 2020

A New Study Claims to Disprove Dark Energy—but Cosmologists Aren’t Convinced

Posted by in category: cosmology

It would be really, really exciting if a single observation could completely overturn astrophysicists’ current understanding of the universe. But that hasn’t happened yet, at least with regards to dark energy.

This week, a press release proclaimed that “new evidence shows that the key assumption made in the discovery of dark energy is in error,” garnering some attention from astronomers and riling up science skeptics. But scientists have already identified some issues with the paper’s claims.

Jan 10, 2020

Massive Black Hole Mystery Solved With a Stripped Helium Star

Posted by in category: cosmology

When David Poses As Goliath

Stellar black holes form when massive stars end their life in a dramatic collapse. Observations have shown that stellar black holes typically have masses of about ten times that of the Sun, in accordance with the theory of stellar evolution. Recently, a Chinese team of astronomers claimed to have discovered a black hole as massive as 70 solar masses, which, if confirmed, would severely challenge the current view of stellar evolution. The publication immediately triggered theoretical investigations as well as additional observations by other astrophysicists.

Among those to take a closer look at the object was a team of astronomers from the Universities of Erlangen-Nürnberg and Potsdam. They discovered that it may not necessarily be a black hole at all, but possibly a massive neutron star or even an ‘ordinary’ star. Their results have now been published as a highlight-paper in the renowned journal Astronomy & Astrophysics.

Jan 9, 2020

What’s a safe distance between us and a supernova?

Posted by in category: cosmology

And how many potentially exploding stars are located within the unsafe distance?

Jan 7, 2020

Strange Dark Matter Findings Could Rewrite the Universe’s History

Posted by in category: cosmology

Scientists believe that mysterious dark matter is key to forming galaxies in the cosmos. Now, a recent series of bizarre findings threatens to undermine everything we think we know.

Jan 2, 2020

Story of the Year: Humanity’s First Look at a Black Hole

Posted by in categories: cosmology, media & arts, transportation

The image, and resulting data, has helped astronomers learn more about black holes in general, and this one in particular, making that two-year wait more than worthwhile. Part of the reason for the delay was simply the logistics of gathering so many observations. Each observatory collects data over a narrow range of wavelengths, resulting in massive amounts of information — the equivalent of up to 5,000 years of mp3 music files. That’s too much to just email someone. Researchers instead had to find ways to physically move that data around. For instance, to transport the information out of the South Pole Telescope in Antarctica, scientists had to wait until spring, when planes finally started flying out again.

Only then could researchers begin the complicated process of stitching together data from the eight observatories, a technique known as interferometry. The team had their work cut out for them: Raw files from each of the observing sites came in with different angles on the sky, in different wavelengths and at different observation times.

“The calibrating and working with it took many months,” Özel says. “And at the end we synthesize it into a single image.” But that’s still not the end of the work, she says. “[You] spend another six months worrying about all the things you might have done wrong, and ask yourself more and more questions, until finally you can be certain that what you have is real.”

Continue reading “Story of the Year: Humanity’s First Look at a Black Hole” »

Jan 1, 2020

This Is How The Universe Changes With Every New Year That Passes

Posted by in category: cosmology

With each new year that comes upon us, there are a slew of new events awaiting us not only here on Earth, but throughout the entire observable Universe. Despite all appearances that things don’t change very much, particularly on cosmic scales, our planet, the Solar System, the galaxy, and even the entire Universe all undergo significant metamorphoses that are not only detectable, but that cumulatively add up as time goes on.

It might be easy to notice the major events as Earth orbits the Sun, such as the changing moon phases, eclipses, meteor showers, and comets passing through our skies. Variable stars change their appearances, new stars form, and old stars die. Occasionally we’ll even witness a cataclysmic event, such as a supernova, black hole merger, or gamma-ray burst. But even a single year can herald some amazing ways our Universe is forever altered.

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