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Questions tagged [black-hole]

Questions regarding points of extremely high mass density, which creates an extremely strong gravitational field from which light cannot escape.

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Do all galaxies have a black hole in the center?

Would I be correct if I stated that all galaxies have a black hole in the center? Since other galaxies orbit around a center point in a galaxy - the barycenter, right? - I would assume at this point ...
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Could Planet Nine be a tiny black hole or an exotic compact object such that it escaped detection? What would its bounds be?

Planet Nine (a variant of the old X-Planet and Tyche-Thelistos hypothesis) proposes a super-earth planet at the edges of the solar system with a mass of around ten Earths. However, given the interest ...
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Since gravity is like an indent on a piece of paper (the space/time matrix) to a marble, can the black hole eventually suck in the matrix?

Can a black hole suck in time? People claim that if you were to put a bowling ball on a trampoline and rolled much smaller balls through the deppression, some would stay in "orbit", some would roll ...
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Could a black hole pass quiescently through the Oort cloud?

Imagine a stellar-mass black hole passing through the Oort cloud, perhaps a quarter to half a light-year from the Sun. How black would the black hole be? That is, any matter that fell into the black ...
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What cosmic disaster is most likely to happen? [closed]

Of all the different ways that the Earth can be destroyed what ways is the most likely that could happen?
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Could Black holes forge heavier elements that have yet to be discovered?

Observations The heaviest elements known in abundance in nature are forged deep within stars. These elements are made possible by the high densities/pressures within the stars. Black holes are known ...
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Once a black hole is formed, is there anything other than Hawking radiation which shortens its life?

Hawking radiation is supposed to very slowly evaporate a black hole (terms and conditions apply :] ). Apart from Hawking radiation, is there any mechanism or effect that can make a black hole cease ...
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How does the center of a black hole can contain so much mass? [duplicate]

We know that "In the center of a black hole is a gravitational singularity, a one-dimensional point which contains a huge mass in an infinitely small space, where density and gravity become ...
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Primordial black holes as a candidate for dark matter

On the Wikipedia page for Primordial Black Holes, a section reads: "Other problems for which primordial black holes have been suggested as a solution include the dark matter problem..." However, this ...
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Movement of the Sun in space

Does the Sun undergo any cycles or revolutions approximately every 24,000 years or 8.6 million years? In Hinduism it is believed that the Sun revolves in an elliptical orbit around a large mass at ...
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Astrophysical Jet Size?

I am wondering about what is the estimated size of astrophysical jet that shoots out from a black hole, I don’t know if it is determined by the size of a black hole. What would classify a black hole ...
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What is Propeller Effect exactly?

I find the original reference seems to be here. I still do not understand the mechanism. It is necessarily occur in neutron binaries? Anyone can introduce it in detail? This paper is old.
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What exactly is the accretion disk?

Is it really possible for material such as dust, gas and other stellar debris that come near the black hole, doesn't fall into it, instead forms a flattened band of spinning material?
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Why can't a quasistar exist now?

From my research, I found out that quasistars theoretically existed because of a black hole core whose radiation pressure counteracted gravity within the star. However, a few websites stated that ...
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Can black holes be used as an energy source

I’ve heard that black hole will be rotating continuously which stores a huge amount of energy in its rotation. Will this energy be accessible, since the rotation is imposed on the space outside the ...
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Are black holes really black? [closed]

I don’t think that black holes are really black as they are the only ones who have the capacity to bend light. At the centre of the black hole the laws of physics are totally defied, black holes ...
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Has the Penrose process ever been linked to an observed phenomenon in some way?

This answer mentions the Penrose process as a potential mechanism that could change the axis of the orbital angular momentum of an accretion disk around a black hole away from the original axis of the ...
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Star - Black Hole binary. Star core Collapses. Does the black hole immediately grow from neutrinos?

I was reading on how Type II Supernovae release as much as 99% of their energy as neutrinos. So I was thinking: suppose there was a large star and black hole binary system, but the two were not close ...
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Black Holes and Worm Holes [closed]

Can a Black Hole enter inside a Worm hole? If yes then what will a observer observe if it present at the another side of Worm hole?
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What defines the plane of an accretion disk around a black hole?

This may be a noob question, your patience is appreciated. The question Do we know at which angle the Event Horizon Telescope will look at the accretion disk of Sagittarius A*? about just how close ...
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Black-hole becoming a star again - follow-up question [closed]

Some questions have been posed about black holes becoming stars again once they attract enough hydrogen/atomic matter from another star. Some answers were a forceful NO. Never. However - let's ponder ...
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What fractions of matter are retained and displaced by quasars?

Following on from a query concerning quasar mass, what fraction of matter is ejected compared to matter that is lost to the BH? Is there a graph that describes the fractions of the mass of quasars ...
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Why is the Innermost Stable Circular Orbit (ISCO) of a non-rotating black-hole 3 times the Schwarzschild radius?

If anyone has a derivation of this result, it would be appreciated greatly.
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What is the actual black hole merger speed?

I have seen models of 2 black hole mergers. https://www.theverge.com/2017/11/16/16665132/gravitational-waves-ligo-virgo-black-holes-merger-multi-messenger-astronomy When we see a space ship appear ...
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Can “rogue” supermassive black holes be made this way?

Could two galaxies (one big and one small)intersect at a velocity to allow the smaller black hole to escape but not the galaxy around it?
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What is the fastest a galaxy or other body has been measured to (or can) travel?

Our solar system travels at an average speed of 515,000 mph and our galaxy at 1.3 million mph through space. What is the fastest moving body in space recorded and the fastest can a black hole or ...
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How do isolated binary compact systems survive their formational supernovae?

In a broad sense I'm trying to understand how a binary black hole or neutron star systems can form from isolated binary massive star systems (i.e., other than from migration within rich BH/NS clusters)...
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Will a black hole swallow the universe?

If black holes swallow stuff, will a big black hole eventually swallow the universe? The universe will eventually go dark, because there will not be enough matter to make stars, and all that will be ...
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Can a black hole be torn apart by SMBHs?

Suppose two SMBHs (supermassive black holes) are brought close (e.g. during a galactic merger). Suppose that a "normal" black hole drifts into the space between the SMBHs. Could the gravitational pull ...
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How loud would a black hole be?

If we could hear black holes, how loud would they be? I know that this is basically the same question as the question "How loud would the Sun be?", except this time there is a black hole. But since ...
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Can a stellar mass black hole swallow Earth?

In the Astronomy magazine I read that the stellar mass black holes are only the size of Rhode Island. Can they swallow Earth?
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Why smaller black holes are considered to be more dangerous than bigger black holes?

More massive the body is more is the gravity.Still often smaller black holes are considered to be very dangerous than the bigger ones,why?
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What does a black hole elements consists of

what are the elements of a black hole it just says what a black hole is? there must be elements that the sun consists of right?
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Physical measurements and celerity of black hole mergers?

LIGO detected a black hole merger for bh's of about 30 solar masses, with a schwartzchild radii of about 20km. Were the gravity waves generated by masses distanced by a few microns or a few ...
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Would LIGO Detect Head-On Collision?

Assume two black holes collide head-on. In other words, they were not orbiting one another before the collision. I know this is unlikely. Further assume that their sizes and distance from Earth are ...
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Why do neutron stars collide instead of just revolving around each other like planets revolve around the Sun?

We know about events like two neutron star colliding and resulting in a black hole, also collision of black holes, and collision of galaxies. But we never see a satellite such as a moon colliding with ...
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What will happen to the shape of a galaxy when a super massive black hole lying in its center dies(evaporates out)?

What's at the Center of the Milky Way? In this article it is said that a supermassive black hole lies in the center of milky way galaxy. At its center, surrounded by 200-400 billion stars and ...
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Why black holes are extremely cold?

"The most massive black holes in the Universe, the supermassive black holes with millions of times the math [sic] of the Sun will have a temperature of 1.4 x $10^{-14}$ Kelvin. That's low. Almost ...
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When black holes forms out of a supernova do they have a very high velocity?

When black holes forms out of a supernova do they have a very high velocity ?? Or do they remains at the position of parent star ??
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Black holes the project stuff out of them? [duplicate]

I was wondering how can a black hole regurgitate anything from it. I have seen pictures or illustrations of a black hole having two point of stuff coming out. I always thought of a black hole ...
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Is star a necessary phase in black hole lifecycle?

It now seems general fact that when a massive star core collapses at the end of its lifecycle it forms a black hole, can a black hole be formed skipping the star phase altogether?
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Can a black hole undergo a Penrose process inside another black hole's ergosphere?

I recently watched this video on black holes: https://www.youtube.com/watch?v=ulCdoCfw-bY And that statement should give you an idea of my level of understanding :) I was wondering if a spinning ...
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Black Hole growth [duplicate]

The latest info on black holes with regard to their formation is that since space and time go to infinity at the event horizon, from an outside perspective nothing ever enters a black hole, and it ...
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Star formation around rotating black holes?

Please excuse an amateur question. While trying to think of anything but what was happening during a dental procedure my mind turned to a model of a star close to a rotating black hole and the ...
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Is there a possibility that a white dwarf can turn into a neutron star or a black hole?

I know that a white dwarf is mainly balanced by electron degeneracy pressure and that if it gains more than 1.4 solar masses from any source (such as a companion star or a collision), it explodes as a ...
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Information Paradox with Hawking's Radiation

A theory about Blackholes storing the information from the universe. Being said that Blackholes are condensed mass sufficient enough to break every particle into different elementary particles, ...
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Are black holes different sizes thanks to the different sized stars that created them? [duplicate]

If the point in space that belongs to the collapsed star (that formed the black hole) is infinitely dense, why are black holes different sizes? Is it due to them feeding on stars and everything else ...
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Strange behaviour of black holes [duplicate]

We know black holes emit streams of radiation ,also recently discovered that they emit visible light when they eat any nearby matter . "We find that activity in the vicinity of a black hole ...
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Theoretically what happens to a black hole that evaporates?

Theoretically, does an evaporating black hole remain a black hole until it evaporates to nothing? Or does it change into something else once it evaporates to below a certain mass?
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Why does kerr black holes have a ring shaped singularity rather than point?

I read about ring singularity on Wikipedia and didn't quite understand the flow of liquids inside a rotating body causing a ring shaped singularity with zero thickness. Moreover is it specifically ...