Archive for the ‘cosmology’ category: Page 9

Mar 26, 2022

Black holes found to exert a pressure on their environment

Posted by in categories: cosmology, physics

Physicists at the University of Sussex have discovered that black holes exert a pressure on their environment, in a scientific first.

In 1974 Stephen Hawking made the seminal discovery that emit thermal radiation. Previous to that, black holes were believed to be inert, the final stages of a dying heavy star.

The University of Sussex scientists have shown that they are in fact even more complex thermodynamic systems, with not only a temperature but also a .

Mar 26, 2022

One Lab’s Quest to Build Space-Time Out of Quantum Particles

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

The prospects for directly testing a theory of quantum gravity are poor, to put it mildly. To probe the ultra-tiny Planck scale, where quantum gravitational effects appear, you would need a particle accelerator as big as the Milky Way galaxy. Likewise, black holes hold singularities that are governed by quantum gravity, but no black holes are particularly close by — and even if they were, we could never hope to see what’s inside. Quantum gravity was also at work in the first moments of the Big Bang, but direct signals from that era are long gone, leaving us to decipher subtle clues that first appeared hundreds of thousands of years later.

But in a small lab just outside Palo Alto, the Stanford University professor Monika Schleier-Smith and her team are trying a different way to test quantum gravity, without black holes or galaxy-size particle accelerators. Physicists have been suggesting for over a decade that gravity — and even space-time itself — may emerge from a strange quantum connection called entanglement. Schleier-Smith and her collaborators are reverse-engineering the process. By engineering highly entangled quantum systems in a tabletop experiment, Schleier-Smith hopes to produce something that looks and acts like the warped space-time predicted by Albert Einstein’s theory of general relativity.

Mar 24, 2022

Star’s Mysterious Orbit Around Black Hole Proves Einstein Was Right— Again

Posted by in categories: cosmology, physics

Star’s mysterious orbit around black hole proves einstein was right all along—again.

The star, known as S2, has a 16-year elliptical orbit. It came near 20 billion kilometers of our black hole, Sagittarius A*, last year. If Isaac Newton’s traditional definition of gravity is correct, S2 should then continue on its previous orbit’s course through space. But it didn’t work.

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Mar 22, 2022

Supermassive black holes put a brake on stellar births

Posted by in categories: cosmology, robotics/AI

Black holes with masses equivalent to millions of suns do put a brake on the birth of new stars, say astronomers. Using machine learning and three state-of-the-art simulations to back up results from a large sky survey, researchers from the University of Cambridge have resolved a 20-year long debate on the formation of stars.

Star formation in galaxies has long been a focal point of astronomy research. Decades of successful observations and theoretical modeling resulted in our good understanding of how gas collapses to form new stars both in and beyond our own Milky Way. However, thanks to all-sky observing programs like the Sloan Digital Sky Survey (SDSS), astronomers realized that not all galaxies in the local Universe are actively star-forming—there exists an abundant population of “quiescent” objects which form stars at significantly lower rates.

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Mar 22, 2022

Astronomers reveal best image yet of mysterious odd radio circles in space

Posted by in category: cosmology

Astronomy’s newest mystery objects⁠—odd radio circles, or ORCs⁠—have been pulled into sharp focus by an international team of astronomers using the world’s most capable radio telescopes.

When first revealed in 2020 by the ASKAP , owned and operated by Australia’s national science agency CSIRO, odd radio circles quickly became objects of fascination. Theories on what causes them ranged from galactic shockwaves to the throats of wormholes.

A new detailed image, captured by the South African Radio Astronomy Observatory’s MeerKAT radio telescope and published today in Monthly Notices of the Royal Astronomical Society, is providing researchers with more information to help narrow down those theories.

Mar 22, 2022

Scientists unveiled the largest number of gravitational waves ever detected

Posted by in categories: cosmology, physics

Universe has an abundance of gravitational wave sources. Recently, an international team of scientists unveiled a tsunami of gravitational waves. This discovery is the most significant number of gravitational waves ever detected.

Scientists detected 35 new gravitational waves. These waves were formed by merging black holes or neutron stars and black holes smashing together. The observation was made by the LIGO and Virgo observatories between November 2019 and March 2020.

This brings the total number of detections to 90 after three observing runs between 2015 and 2020.

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Mar 21, 2022

This tiny particle accelerator fits into a large room, making it much more practical than the one from CERN

Posted by in categories: cosmology, particle physics

As scientists prepared in 2010 to collapse the first particles in the Large Hadron Collider (LHC), media representatives imagined that the EU-wide experiment could create a black hole that could swallow and destroy our planet. How on earth, columnists rage, could scientists justify such a dangerous indulgence for the pursuit of abstract, theoretical knowledge?

Mar 20, 2022

The Beginning to the End of the Universe: How black holes die

Posted by in category: cosmology

Circa 2021

This story comes from our special January 2021 issue, “The Beginning and the End of the Universe.” Click here to purchase the full issue.

But even the black holes will one day die. And when they do, these monsters won’t go gently into the night. A burst of fireworks will light up the universe in the final moments of each black hole, heralding the end of the era.

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Mar 20, 2022

How Quantum Physics Allows Us To See Back Through Space And Time

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

The problem is that transitions from one s-orbital to another are forbidden, quantum mechanically. There’s no way to emit one photon from an s-orbital and have your electron wind up in a lower energy s-orbital, so the transition we talked about earlier, where you emit a Lyman-series photon, can only occur from the 2 p state to the 1s state.

But there is a special, rare process that can occur: a two-photon transition from the 2s state (or the 3s, or 4s, or even the 3 d orbital) down to the ground (1s) state. It occurs only about 0.000001% as frequently as the Lyman-series transitions, but each occurrence nets us one new neutral hydrogen atom. This quantum mechanical quirk is the primary method of creating neutral hydrogen atoms in the Universe.

If it weren’t for this rare transition, from higher energy spherical orbitals to lower energy spherical orbitals, our Universe would look incredibly different in detail. We would have different numbers and magnitudes of acoustic peaks in the cosmic microwave background, and hence a different set of seed fluctuations for our Universe to build its large-scale structure out of. The ionization history of our Universe would be different; it would take longer for the first stars to form; and the light from the leftover glow of the Big Bang would only take us back to 790,000 years after the Big Bang, rather than the 380,000 years we get today.

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Mar 18, 2022

Pulsar Shoots 7-light-year-long Phaser Blast

Posted by in categories: cosmology, particle physics

Nature proves truth is still stranger than fiction: A pulsar has shot energetic particles in a thin, straight line that extends for light-years into space. The discovery might explain how antimatter makes its way to Earth.

Star Trek can keep its ray guns — pulsars make far more powerful beams of radiation.

Crushed stellar cores, left behind when a massive star goes supernova, are among nature’s own particle accelerators. Though pulsars are only the size of Manhattan, their dizzying spins and powerful magnetic fields can energize particles to a significant fraction of the speed of light. In addition, pulsars glow with high-energy radiation, which can itself convert into pairs of electrons and their antimatter counterpart, positrons.

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