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Archive for the ‘cosmology’ category: Page 18

Jan 31, 2024

What was it like when dark energy rose to prominence?

Posted by in category: cosmology

But after a few billion years, something fishy begins to occur. Instead of approaching zero, the expansion rate starts to decrease at a slower rate than one would expect, and a distant galaxy’s recession speed doesn’t drop in the same fashion anymore. Once the Universe reaches an age that’s 7.8 billion years after the Big Bang, things start to get weird: these distant galaxies stop slowing down in their recession entirely, and appear to “coast” in the sense that they move away from us at a constant speed from moment-to-moment, as though the expansion had stopped decelerating.

And then, as the Universe continues to age, the recession speeds no longer remain constant, nor do they go back to decreasing. Instead, these distant galaxies appear to recede from us (and one another) more and more quickly. It’s as though some effect is causing the expansion to neither decelerate nor remain constant, but to actually increase and accelerate!

Jan 31, 2024

Tapping Into The Power of a Hypothetical Black Hole Could Create an Insane Bomb

Posted by in category: cosmology

Black holes are powerful gravitational engines. So you might imagine that there must be a way to extract energy from them given the chance, and you’d be right.

Certainly, we could tap into all the heat and kinetic energy of a black hole’s accretion disk and jets, but even if all you had was a black hole in empty space, you could still extract energy from a trick known as the Penrose process.

First proposed by Roger Penrose in 1971, it is a way to extract rotational energy from a black hole. It uses an effect known as frame dragging, where a rotating body twists nearby space in such a way that an object falling toward the body is dragged slightly along the path of rotation.

Jan 29, 2024

Scientists Use Supercomputer To Unravel Mysteries of Dark Matter and the Universe’s Evolution

Posted by in categories: cosmology, evolution, particle physics, supercomputing

“The memory requirements for PRIYA simulations are so big you cannot put them on anything other than a supercomputer,” Bird said.

TACC awarded Bird a Leadership Resource Allocation on the Frontera supercomputer. Additionally, analysis computations were performed using the resources of the UC Riverside High-Performance Computer Cluster.

The PRIYA simulations on Frontera are some of the largest cosmological simulations yet made, needing over 100,000 core-hours to simulate a system of 30723 (about 29 billion) particles in a ‘box’ 120 megaparsecs on edge, or about 3.91 million light-years across. PRIYA simulations consumed over 600,000 node hours on Frontera.

Jan 28, 2024

MIT physicists discover surprising twist in Milky Way’s core

Posted by in categories: cosmology, physics

MIT physicists have discovered a surprising twist in the Milky Way’s rotation curve that challenges our understanding of dark matter. By tracking the speed of stars across the galaxy, they’ve uncovered a potential deficit of dark matter at the galactic core.

Traditionally, astronomers believed that dark matter was responsible for the galaxy’s rotation. Still, the new analysis raises the possibility that the Milky Way’s gravitational center may be lighter in mass than previously thought.

Jan 28, 2024

Ancient philosophers understood a key truth of modern cosmology

Posted by in category: cosmology

Ancient ideas about the Universe describe matter as constantly ebbing and flowing, positioning nature as the ultimate recycler.

Jan 27, 2024

Right again, Einstein: New snapshot of 1st black hole to be photographed confirms relativity

Posted by in categories: cosmology, physics

The new black hole image offers further confirmation for Albert Einstein’s theory of general relativity.

Jan 27, 2024

Theoretical Possibility of Quantum Stabilization of Traversable Wormholes

Posted by in categories: cosmology, quantum physics

In this article, we argue that we can explain quantum stabilization of Morris-Thorne traversable wormholes through quantum mechanics. We suggest that the utilization of dark matter and dark energy, conceptualized as negative mass and negative energy tied to the universe’s information content, can stabilize these wormholes. This approach diverges from the original Morris-Thorne model by incorporating quantum effects, offering a credible and adequate source of the exotic matter needed to prevent wormhole collapse. We reassess the wormholes’ stability and information content considering the new calculated revised vacuum energy based on the mass of bit of information. This new calculation makes the wormholes more viable within our universe’s limits.

Jan 26, 2024

Scientists may finally know where the biggest, oldest black holes in the universe came from

Posted by in category: cosmology

The presence of supermassive black holes in the earliest epochs of the universe has scientists stumped — but repeated explosions from tiny black holes may offer an explanation.

Jan 26, 2024

JWST turns up even more heavier-than-expected black holes

Posted by in category: cosmology

Astronomers are using it to peer back to near “cosmic dawn,” a time when the first stars and galaxies were forming. And JWST is showing that these early galaxies are different than astronomers had anticipated, in a plethora of ways: Some are settling into shapes we didn’t think were possible so early after the Big Bang. Others are unexpectedly large.

And recent research shows that even the black holes in the early universe were odd — they’re way bigger than they should be, relative to the mass of the galaxy around them. Unexpectedly, JWST is spotting mammoth black holes anchoring relatively small galaxies.

Jan 26, 2024

Startling Signs of Gravity’s Laws Breaking Down Detected in Twin Stars

Posted by in categories: cosmology, quantum physics

In 1,859, French astronomer and mathematician Urbain Le Verrier detected something strange: Mercury deviated in its dance around the Sun, defying the orderly precession predicted by Newtonian physics.

This odd anomaly couldn’t be explained by unknown planets tugging at Mercury’s orbit; only by physicist Albert Einstein’s 1915 general theory of relativity, which describes how gravity creates curves in the fabric of space-time.

Einstein’s general theory has held strong in the century since, but there are a few things about the Universe his mind-bending model can’t explain. It breaks down in the centers of black holes and at the dawn of the Universe, for example, and doesn’t fit very easily with quantum mechanics, leading some physicists to ponder alternative takes on how gravity works.

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