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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What would happen if a small black hole fell into a star?
Let's say you created a cannon that can shoot small black holes and you shoot it at some star.
Would the star just turn into a black hole silently? Or rather first destabilize and produce a last ...
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Could an hypothetical hidden black hole companion to the sun be revealed by proper motion data?
If the Sun were in a binary star system with a black hole companion, the Sun would be orbiting the black hole, and this should be reflected in a change in the observed proper motion of nearby stars.
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How could lithium burning take place in a quasi-star?
According to Begelman et al. (2008), one of the most distinguishing features of the hypothetical quasi-star is that it's supported by radiation pressure from the accretion disk of the black hole in ...
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Can a small black hole orbit a large star?
I recently read about the discovery of a tiny black hole (with only three times the mass of the sun) nicknamed ‘The unicorn’ about 1500 light years from earth. This got me thinking, can this black ...
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The consequences and the mechanisms of a shift of the Earth away from the sun
First premise: I have already made this question in the worldbuilding section, but since it is a very specific question many have recommended me to write in the astronomy section so here we are.
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Why do we not call black holes black stars or dark stars?
I've never understood why the term black holes are widely used to describe what is actually a black star or dark star. I mean why name something just because of its extreme space curvature effects? In ...
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Is there a maximum size for a black hole?
As far as I understand it black holes radiate Hawking radiation and probably gravity waves, which over time causes them to lose mass and eventually evaporate after almost unfathomable amounts of time. ...
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Would gravitational waves be subject to external gravitational perturbations?
Given that the gravitational wave detected by LIGO was a very weak echo of a very distant event, could it have been "deviated" and distorted on its way here by a sufficiently massive black hole in ...
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Binaries consisting of a black hole and a non-black hole?
Are there any known binary systems in which one member is a black hole and the other is not a black hole (main sequence star, giant, neutron star, white dwarf, whatever)?
Googling seems to turn up ...
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How can Kerr black holes have a 'speed limit' to how fast they can spin?
Obviously, the speed of light is a presumed limit, at least for 'physical' objects moving 'within' ('through'?) spacetime, but...
In recent news some scientists believe they have figured out the ...
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How did the Milky Way quasar not disrupt life on Earth?
According to most sources of information I have found (A Quora answer and books), when galaxies become quasars, they destroy all life in their host galaxy, as they output so much radiation that they ...
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Can black holes even exist [if mass cannot be retained near the collapse threshold]?
A black hole happens because enough material mass exists in an area to create a gravitational field strong enough that nothing escapes (including light). This gravity also exceeds the strength of ...
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Amount of black holes over time
Hello the number of black holes is much bigger than the number of black holes in the past right?Let $b$ be the number of black holes in the universe.Obviously $\frac{db}{dt}>0$ but what about $\...
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Population growth of black holes [duplicate]
As any population, the population of black holes is found by the population growth equation:
$\frac{dB(t)}{dt} = c(t)B(t)-d(t)B(t)$.Which are $c(t)$ and $d(t)$ for Black holes?
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JWST Early Black Holes: Gas Collapsed To Metallic Hydrogen Core?
I was reading an article about early black holes found by JWST at Redshift 9. And saw that there was wonder at how large amounts of gas could collapse into a black hole as a theory.
So my question is ...
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Is the largest black hole larger than the Solar System?
Yes. Ton-618 is the largest black hole, and if it was replaced with our solar system, it would reach far after the end of the solar system, which is called the Kuiper Belt. Ton-618 has a mass 66 ...
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Are gravitational waves emitted equally in all directions?
I have a question regarding gravitational waves that I can't figure out. Hope some wise minds here can help a simple amateur without technical or scientific education.
Two black holes rotating around ...
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Black hole collision
In a situation where 2 black holes are close to colliding, but do not collide, can one black hole free/steal matter from the other in passing if the event horizons brush?
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What is the "hypothesized lower mass gap" between 2.5 and 5 solar masses?
Searching here for "mass gap" yields nothing yet. Penn State's Black hole or neutron star? LIGO-Virgo scientists find mystery object in 'mass gap' begins:
When the most massive stars die, ...
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From an outsider's perspective, how can a black hole grow if nothing ever crosses the event horizon?
Due to time dilation, an outside observer never sees a falling object actually cross the event horizon. I'm not referring to the optical illusion of red-shifted light making objects appear to fade ...
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How does a neutron star collapse into a black hole?
We know the spectacular explosions of supernovae, that when massive enough, form black holes. The explosive emission of both electromagnetic radiation and massive amounts of matter is clearly ...
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How do we know that black holes are spinning?
How is it possible to know if a black hole is spinning or not?
If a planet is spinning, you can see it clearly but you can't really see a black hole.
Next thing would be that matter interacts with ...
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If two black hole event horizons overlap (touch) can they ever separate again?
Hypothetical question based on my understanding that two event horizons that overlap (touch) can't ever separate again:
Imagine a 1 billion solar mass black hole (so the event horizon is massive and ...
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Can gravitational waves pass through a black hole?
As the title says, what happens when a gravitational wave approaches a black hole? I would presume that something interesting happens because of the way spacetime works near black holes but I have no ...
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Does matter accumulate just outside the event horizon of a black hole?
My understanding is that time slows and approaches stopping when approaching the event horizon of a black hole. I have seen this explained several places, including a brief explanation in the last ...
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How do stars 1 billion times the volume of our sun form and can they become black holes?
UY Scuti is a star 1 billion times the volume of our sun.
A billion solar mass black hole formed 750 million years after the Big Bang.
Could it have formed from a star like UY Scuti?
Rare black hole ...
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Possibility for black holes having negative energy
new to the community here. The question I have is whether black holes can possibly contain negative energy of any sort?
It’s not a carefully thought-out question as space is not my bailiwick.
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Is there a limit to the Schwarzschild radius?
The Schwarzschild radius is a way for us to calculate the extent to which something has to be shrunk in order for it to become a black hole but I was wondering is there a limit to the object that we ...
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Death of a Black Hole ≠ Rebirth?
So we all know that Stephen Hawking proved that Black Holes do evaporate overtime through hawking radiation. But that energy is released in very discrete amounts and there will be a time in the ...
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Will an overspun black hole be white?
I recently watched a Kurzgesagt video about destroying black holes. In the video, they mentioned that you can (theoretically) "overspin" a black hole to remove its event horizon, thereby ...
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What is a "Gentle Giant" Black Hole?
I have seen articles about the Milky Way's "gentle giant" black hole. For example:
https://nypost.com/2022/05/12/image-of-gentle-giant-black-hole-at-milky-ways-center/
https://www.reuters....
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The event horizon of a black hole
According to https://www.nationalgeographic.com/magazine/article/black-holes-einstein-star-eaters', when something crosses the event horizon of a black hole "A person watching from the outside ...
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Question about how it's possible for black holes to have gravity and a possible resolution [duplicate]
1. Assumptions
1.a: gravity propagates at c (maximum)
1.b: gravitational fields cause time dilation
1.c: escape velocity at the event horizon is c
1.d: gravity "warps" space-time, but in ...
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If you were on a planet orbiting a star that has a black hole companion, could you see light from your host star bent 180 degrees?
I realize that there is a distance from a black hole where photons can orbit. I understand that this orbit is very unstable, but I am concerned with photons just outside this range. Could the black ...
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Can our Sun become a black hole
Does every star become a black hole? Is there any probability that our sun can become a black hole? If yes then is it on its way to become a black hole? what is the current state of sun as per the ...
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Spinning black hole vs non spinning black hole
Does a spinning black hole have a stronger gravity than a non spinning one.After all, a spinning black hole is stretching space-time more, so does that make a difference is gravity?
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Why do Earth and moon move apart but binary black holes move closer?
According to the accepted answer on Is the moon moving further away from Earth and closer to the Sun? Why?, the moon is receding from Earth because tidal forces and friction cause energy to be lost.
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Could both the high incidence of supermassive Black Holes (BH) and the expansion of the universe be consequences of vacuum entanglement energy?
The notion that spacetime may emerge from entanglement between factors comprising a Hilbert space decomposition of the vacuum has been suggested by many (for example, M. Van Raamsdonk “Building up ...
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Is it possible to detect gravitational lensing of both light and gravitational waves originating from the same event?
Is it theoretically possible to detect gravitational lensing of both light and gravitational waves, when both originate from the same source/event (merger of two stellar black holes or merger of two ...
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Could the revolution of super-massive black holes around each other create a pulsar-array gravitational wave signal despite 'final parsec' problem?
Some commentators on the recently-observed very-long-wavelength gravitational wave signal involving pulsars, like Dr. Becky Smethurst, have implied that it might not be merging supermassive black ...
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How do primordial black holes are able to have an event horizon?
How do primordial black holes have an event horizon?
Sorry for the stupid question, but I know primordial black holes have just a handful of mass in a cosmic scale compressed in a singularity. But if ...
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Could observation of GL or other image phenomena from system of 2 merging massive dense objects and of GW caused by their merge be connected?
What is the probability to observe gravitational lensing (or any other image related phenomena) from the pair of black holes (or pair of neutron stars or black hole - neutron star) which are about to ...
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Could "gravitational atom” black hole be detected using observation of gravitational microlensing?
D. Baumann et al., published the article hypothesizing existence of "gravitational atom” black holes (not sure whether those are just stellar ones or also those could be supermassive black holes ...
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Angular size of an object falling into a black hole
People often say that an object freezes over a black hole’s event horizon as it falls in. This is because only a finite amount of proper time passes for the object before it crosses the event horizon. ...
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From where does the energy for gravitational waves come from?
As far as I understand, in the events detected by LIGO, about 4% of the total mass of merging binary black holes was converted to gravitational waves.
Where does this energy come from, i.e. what ...
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Could we (Earth, Humanity, Solar System) be falling into a black hole?
With the expansion of the universe, all objects far away from us appear to be moving away (ie: exhibit Redshift). With distance, this acceleration / redshift also seems to increase (~73,000 (m/s) / (...
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What is the mechanism through which mass is converted to thermal energy in the accretion disc of a black hole?
In the book The Cosmic Perspective, it is stated that as matter is falling into a supermassive black hole, up to $40\%$ of its mass are converted to thermal energy, making the accretion of matter ...
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Can a Thorne-Żytkow object be the progenitor of a modern quasi-star?
I was reading some Wikipedia articles about astronomy, and came across an interesting line:
The neutron star may also accrete sufficient material to collapse into a black hole.
Now, here is my ...
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Can a quasi-star develop a stable crust?
Could a quasi-star potentially develop a stable outer layer or crust during its early stage of formation if it were to be bombarded with substantial amounts of matter, coexisting with its core and the ...
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Could You Escape an Event Horizon by increasing a Black Hole's velocity?
I have an idea for trying to escape the black hole's event horizon that might make basically no sense and I want it double checked. Basically, I do know that you can't escape the event horizon unless ...
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