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Archive for the ‘cosmology’ category: Page 129

Jun 3, 2023

Another Way for Black Holes to Evaporate

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

The quantum fluctuations that pervade empty space spontaneously give birth to pairs of particles and antiparticles. Ordinarily, these pairs annihilate so promptly that their existence is virtual. But a powerful field can pull a pair’s members apart for long enough that their existence becomes real. In 1951 Julian Schwinger calculated how strong an electric field needs to be to beget electron–positron pairs. Now Michael Wondrak and his colleagues of Radboud University in the Netherlands have proposed that particle pairs can be brought into existence by the immense gravitational tidal forces around a black hole [1].

Wondrak and his colleagues considered all the paths a pair of virtual particles could take during their brief existence. If the vacuum is stable, all pairs that are created are also destroyed. But a strong field destabilizes the vacuum, makes some paths more likely than others, and leads to a deficit of pairs that recombine. The deficit is balanced by a net outflow of real particles, which, in the case of a black hole’s gravitational field, leads to the black hole’s eventual evaporation.

The theorists’ approach is sufficiently general that it could reproduce not only Schwinger’s effect but also Stephen Hawking’s 1974 proposal that if a particle–antiparticle pair springs into virtual existence near a black hole’s event horizon, one member could fall in while the other escapes. What’s more, the researchers found that Hawking’s effect is a special case of a more general phenomenon. Pulling virtual particles into existence depends only on the stretching of spacetime wrought by a curved gravitational field and does not require an event horizon as Hawking originally suggested. One intriguing implication is that a neutron star, whose Schwarzschild radius lies beneath the stellar surface, can also beget particle pairs and decay.

Jun 3, 2023

Supermassive Black Holes Can Blow Winds Up to a Third of The Speed of Light

Posted by in categories: cosmology, evolution

They are known as ultra-fast outflows (UFOs), powerful space winds emitted by the supermassive black holes (SMBHs) at the center of active galactic nuclei (AGNs) – aka. “quasars.” These winds (with a fun name!) move close to the speed of light (relativistic speeds) and regulate the behavior of SMBHs during their active phase.

These gas emissions are believed to fuel the process of star formation in galaxies but are not yet well understood. Astronomers are interested in learning more about them to improve our understanding of what governs galactic evolution.

This is the purpose of the SUper massive Black hole Winds in the x-rAYS (SUBWAYS) project, an international research effort dedicated to studying quasars using the ESA’s XMM-Newton space telescope.

Jun 2, 2023

NASA detects large thermonuclear explosion in space caused by pulsar

Posted by in category: cosmology

NASA recently made an extraordinary discovery of a large thermonuclear explosion in space, caused by a pulsar, which is the remains of a star that did not explode to form a black hole. The National Aeronautics and Space Administration was able to detect the explosion thanks to the strong beam of X-rays sent out by the burst, which was picked up by the agency’s orbiting observatory NICER.

This discovery serves as a potent reminder of the dangers that lurk in space. According to a study published in The Astrophysical Journal Letters in August, the burst released as much energy as the sun does in ten days in just twenty seconds.

The leader of the study and astrophysicist, Peter Bult, said in a statement from NASA, “This burst was great.” Bult also added that the study revealed a two-step change in brightness that they believe was caused by the ejection of separate layers from the pulsar’s surface. These features provide significant information to understand how these events work.

Jun 1, 2023

Another Major Dark Matter Mystery Challenges Scientists

Posted by in category: cosmology

I wrote a foreword for this awesome Sci-Fi book here: https://amzn.to/3aGrg0I
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Hello and welcome! My name is Anton and in this video, we will talk about a strange discovery of excess of dark matter and other related mysteries.
Paper: https://arxiv.org/pdf/2007.15633.pdf.
Paper: https://science.sciencemag.org/content/369/6509/1347
Illustris Project: https://www.illustris-project.org/explorer/

Continue reading “Another Major Dark Matter Mystery Challenges Scientists” »

May 31, 2023

Signs of a Critical Imbalance in Physics Seen in The Arrangements of Galaxies

Posted by in categories: cosmology, physics

Physicists have long puzzled over why there is more matter in the Universe than its flipped twin, antimatter. Without this imbalance, the two types of material would have canceled out, leaving nothing but a boring glow in the vast emptiness of space.

Somehow, at some point, something changed in the way the Universe works on a fundamental level, favoring the mirrored state – or parity – of one kind of ‘stuff’ over the other.

Continue reading “Signs of a Critical Imbalance in Physics Seen in The Arrangements of Galaxies” »

May 31, 2023

A Cosmic Conundrum: The Black Hole That Creates Stars, Defying Conventional Wisdom

Posted by in category: cosmology

A recent discovery made by astronomers operating the Hubble Space Telescope has revealed the presence of a black hole at the center of a dwarf galaxy that actually creates stars instead of consuming them. This revelation has challenged the common perception that black holes only destroy matter.

The method by which stars are formed in this particular dwarf galaxy, named Henize 2–10, is fundamentally different from how stars are formed in larger galaxies. Astronomers have observed that gas moves around the black hole before merging with a core of dense gas present in the galaxy.

The Hubble spectroscopy revealed that the outflow of this gas was traveling at a rate of a million miles per hour, which eventually collided with the dense gas present in the galaxy. The outflow created clusters of newly born stars on its path.

May 31, 2023

Meet “Vacuum Decay” — The Most Spectacular End To The Universe

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

There is a lot of speculation about the end of the universe. Humans love a good ending after all. We know that the universe started with the Big Bang and it has been going for almost 14 billion years. But how the curtain call of the cosmos occurs is not certain yet. There are, of course, hypothetical scenarios: the universe might continue to expand and cool down until it reaches absolute zero, or it might collapse back onto itself in the so-called Big Crunch. Among the alternatives to these two leading theories is “vacuum decay”, and it is spectacular – in an end-of-everything kind of way.

While the heat death hypothesis has the end slowly coming and the Big Crunch sees a reversal of the universe’s expansion at some point in the future, the vacuum decay requires that one spot of the universe suddenly transforms into something else. And that would be very bad news.

There is a field that spreads across the universe called the Higgs field. Interaction between this field and particles is what gives the particles mass. A quantum field is said to be in its vacuum state if it can’t lose any energy but we do not know if that’s true for the Higgs field, so it’s possible that the field is in a false vacuum at some point in the future. Picture the energy like a mountain. The lowest possible energy is a valley but as the field rolled down the slopes it might have encountered a small valley on the side of that mountain and got stuck there.

May 31, 2023

Black Holes Might Really Be Giant Structures Made of Spacetime, Physicists Propose

Posted by in categories: cosmology, physics

“It’s an interesting question to ask: Are there things other than a black hole” that “will give you a hint about what new physics could look like?” added Bah. “But before you get there, you need to know how to tell whether you have a black hole or not, and to do that you have some prototype examples of things that are not black holes to be able to compare.”

Black holes are among the most fascinating and puzzling objects ever observed in our universe. These massive compact entities have so much gravitational power that nothing, not even light, can escape beyond their borders, known as the event horizon. Scientists have imaged black holes with the Event Horizon Telescope and have captured the ripples that these objects make in spacetime, which are called gravitational waves.

May 31, 2023

Before the Big Bang 11: Is the Universe a Time Machine?

Posted by in categories: cosmology, evolution, quantum physics, time travel

What happened before the Big Bang? In two of our previous films we examined cyclic cosmologies and time travel universe models. Specially, the Gott and Li Model https://www.youtube.com/watch?v=79LciHWV4Qs) and Penrose’s Conformal Cyclic Cosmology https://www.youtube.com/watch?v=FVDJJVoTx7s). Recently Beth Gould and Niayesh Afshordi of the Perimeter Institute for Theoretical Physics have fused these two models together to create a startling new vision of the universe. In this film they explain their new proposal, known as Periodic Time Cosmology.

0:00 Introduction.
0:45 NIayesh’s story.
1:15 Beth’s story.
2:25 relativity.
3:26 Gott & Li model.
6:23 origins of the PTC model.
8:17 PTC periodic time cosmology.
10:55 Penrose cyclic model.
13:01 Sir Roger Penrose.
14:19 CCC and PTC
15:45 conformal rescaling and the CMB
17:28 assumptions.
18:41 why a time loop?
20:11 empirical test.
23:96 predcitions.
26:19 inflation vs PTC
30:22 gravitational waves.
31:40 cycles and the 2nd law.
32:54 paradoxes.
34:08 causality.
35:17 immortality in a cyclic universe.
38:02 eternal return.
39:21 quantum gravity.
39:57 conclusion.

Continue reading “Before the Big Bang 11: Is the Universe a Time Machine?” »

May 28, 2023

Schrodinger’s black hole? Quantum properties of stellar bodies revealed

Posted by in categories: cosmology, quantum physics

Year 2022 😗


A team of researchers found that a simulated black hole could have multiple masses simultaneously.