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Archive for the ‘cosmology’ category: Page 240

Feb 12, 2020

Astronomers find a star dive-bombing our galaxy’s supermassive black hole

Posted by in category: cosmology

At the center of our galaxy lies Sgr A — a supermassive black hole. With over 4 million times the Sun’s mass, you can see why it gets that moniker.

One reason we know its mass is that there’s a cluster of young, luminous stars orbiting around it. These are called S stars, and they form a group around the black hole about a quarter of a light year across — a few trillion kilometers. One of these stars, S2, has an elliptical orbit that takes it to a distance of just 16 billion kilometers from the black hole as it travels on its elliptical orbit. Until recently, that star had the closest encounter we knew of.

Feb 9, 2020

Galaxy formation simulated without dark matter

Posted by in categories: computing, cosmology

For the first time, researchers from the Universities of Bonn and Strasbourg have simulated the formation of galaxies in a universe without dark matter. To replicate this process on the computer, they have instead modified Newton’s laws of gravity. The galaxies that were created in the computer calculations are similar to those we actually see today. According to the scientists, their assumptions could solve many mysteries of modern cosmology. The results are published in the Astrophysical Journal.

Cosmologists today assume that matter was not distributed entirely evenly after the Big Bang. The denser places attracted more matter from their surroundings due to their stronger gravitational forces. Over the course of several billion years, these accumulations of gas eventually formed the galaxies we see today.

An important ingredient of this theory is the so-called . On the one hand, it is said to be responsible for the initial uneven distribution that led to the agglomeration of the gas clouds. It also explains some puzzling observations. For instance, stars in rotating galaxies often move so fast that they should actually be ejected. It appears that there is an additional source of gravity in the galaxies that prevents this—a kind of “star putty” that cannot be seen with telescopes: dark matter.

Feb 8, 2020

We May Finally Have a Way to Detect Hawking Radiation Leaking From Black Holes

Posted by in categories: cosmology, quantum physics

O.o!


The epic collision between two neutron stars in 2017 really is the science gift that keeps on giving. As they merged, gravitational waves rippled out across the Universe; now reverberations from that event could confirm a decades-old hypothesis about black holes.

Continue reading “We May Finally Have a Way to Detect Hawking Radiation Leaking From Black Holes” »

Feb 8, 2020

The Expanding Universe Might Not Depend On How You Measure It, But When

Posted by in category: cosmology

It’s been called the biggest conundrum in all of cosmology, and recent measurements just add to the confusion.

Feb 6, 2020

Don’t Believe These 5 Myths About The Big Bang

Posted by in category: cosmology

For over 50 years, it’s been the scientifically accepted theory describing the origin of the Universe. It’s time we all learned its truths.

Feb 4, 2020

Oddball sexaquark particles could be immortal, if they exist at all

Posted by in categories: cosmology, particle physics

These supremely stable particles could explain dark matter.

Feb 4, 2020

A new ‘Einstein’ equation suggests wormholes hold the key to quantum gravity

Posted by in categories: cosmology, information science, quantum physics

A new Einsteinian equation, ER=EPR, may be the clue physicists need to merge quantum mechanics with general relativity.

Feb 4, 2020

Quantum weirdness could allow a person-sized wormhole to last forever

Posted by in categories: cosmology, quantum physics

We were unsure if wormholes could exist long enough to allow a person through. Now calculations indicate they are extremely rare, but could last the age of the universe.

Feb 2, 2020

Has a black hole made of sound confirmed Hawking radiation?

Posted by in category: cosmology

One of Stephen Hawking’s predictions seems to have been borne out in a man-made “black hole.”

Jan 29, 2020

Did Scientists Finally Solve the Impossible Physics Riddle?

Posted by in categories: cosmology, physics

A theoretical physicist in England has won a prestigious award for her work on the theory of massive gravity, which could explain why gravity hasn’t constrained the rapid expansion of the universe. The $100,000 award honors the work of Claudia de Rham, who has worked for 10 years on a way to turn massive gravity theory into something measurable.

Cosmologists have puzzled for decades about how to marry gravity with the speed at which the universe is expanding. Gravity as we understand it would work to hold the universe together, not let it race apart from itself into eventual oblivion. Enter the counterpart to dark matter, dark energy, which is what scientists call whatever is pulling the universe apart.