Tagged Questions

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

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5
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2answers
216 views

How deep and shaped is the depth of a black hole?

A common representation of a black hole is a black circle which if I'm correct, indicates its breadth. This representation depicts it as a 'plate', so a really small depth compared to its breadth. ...
0
votes
2answers
133 views

Why did the big bang not just produce a big black hole?

Questions I've often wondered about: 1) If all the matter and energy were concentrated at a single point at the big bang, why wasn't that a black hole, or why didn't it form one? 2) If the reason #1 ...
1
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1answer
70 views

What would happen if a Black Hole and White Hole Collided?

Given our understanding of both black holes and white holes, what would be the outcome if they were both to suddenly collide? Black Holes: A black hole is a region of spacetime from which gravity ...
-1
votes
1answer
95 views

Why don't small stars end up as a black holes?

I've recently done some research about black holes, and I realized that big stars form black holes and small ones don't. Is it because the gravity isn't strong enough for it to fall in on itself, or ...
-2
votes
1answer
89 views

Black Holes, how do they form?

Do black holes form by when the massive star dies and all the gravity falls in on itself, or something else. Please let me know, I'm really desperate!!
1
vote
1answer
51 views

Can a person at a photon sphere of a black hole decide where the black hole is?

A person at the photon sphere of a black hole will observe the following: The black hole surface will cover exactly half of the visible sky (say, the left half), and cosmic horizon will cover the ...
4
votes
2answers
189 views

Do black holes have energy?

So black holes are created by certain dying stars and when the star runs out of nuclear energy gravity wins out and the star implodes. An entire star’s mass collapses down into a smaller and smaller ...
-2
votes
2answers
88 views

why quantum gravity doesnot exist?

I am not an astrophysicist and not its student.All my knowledge about astronomy comes from you tube videos and discovery channel.From them i knew that to solve the mysteries of black hole both ...
2
votes
3answers
212 views

Why isn't the star that created the black hole a black hole?

If the mass of a black hole is creating so much gravity that light cannot escape, why isn't the mass of the star that created the black hole (before it went supernova) trapping light as well? By all ...
1
vote
0answers
37 views

What are the biggest problems about the numerical, finite-element GR models?

As I know, for example the modelling of the collapse of a neutron star (to a black hole) wasn't done correctly until now. Why? Yes, I know, the Einstein Field Equations aren't really easy to solve. ...
3
votes
2answers
86 views

Assuming a sufficient amount of mass above the density threshold, does the actual concentration of the mass matter in creating a black hole?

I've heard that the actual density of a black hole (within the volume of the event horizon) is pretty low - does that mean that any sufficiently large volume of mass over that density is also a black ...
4
votes
2answers
181 views

Is it possible that a ultra-large portion of the space we live in is already inside a black hole? How could we refute this?

Trying to wrap my head around some concepts involving the very large gravitational fields of black holes, and what the gravitational gradients look like on a cosmic scale. I'm familiar with the Great ...
3
votes
1answer
58 views

Hypothetical scenario, two nearby black holes

I've always wondered what would happen if a hypothetical scenario, two black holes meet, with similar proportions: Maybe one swallow the other one? Or would make a bigger one between them.
1
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1answer
89 views

How many light years away is Earth from the closest outer edge of the black hole at the center of the Milky Way?

How many light years is Earth away from the closest outer edge of the supermassive black hole in Sagittarius A* at the center of the Milky Way? I don't mean the distance to the center of the galaxy, ...
1
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2answers
106 views

How do black holes evaporate?

Will black holes evaporate, if they evaporate? When and why do they evaporate? What are the conditions for evaporation? Under what principle do they evaporate?
2
votes
1answer
65 views

What type of energy is escaping from black-hole's poles?

Following this article, it is stated that: As a star drifts too close to a supermassive black hole, intense tidal stresses rip the star to shreds. As this happens, the shredded material will ...
1
vote
1answer
91 views

Contradiction between Theory of Relativity and Newton's Law of Universal Gravitation?

Newton's Law of Universal Gravity states that an object will accelerate constantly as it falls. Let's assume an object falling into a black hole. According to Newton's Law, when it reaches the event ...
2
votes
1answer
84 views

How is space-time bent by black holes?

I just read When a star becomes a black hole, does its gravitational power become stronger? and it confused me a bit; I always thought black holes are supermassive and that is why they bend ...
1
vote
1answer
42 views

Under Earth's gravitational pull, how dense would an object have to be to reach its Schwarzschild Radius?

The Schwarzschild Radius is a theoretical radius, that if the mass of the object was compressed into that certain radius, the escape speed from the surface of the compressed object would equal the ...
4
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2answers
122 views

Observational Evidence for the Existence of Black Holes

What is the direct observational evidence that black holes exist? I have read that black holes have been detected through X-ray emission. What is some other observational evidence for black holes?
1
vote
0answers
35 views

In regards to the holographic principle, what exactly is information?

I'm having trouble understanding what exactly "information" is in the context of the holographic principle suggested by string theory. Can it be equated to a matrix of ones and zeros? Does this ...
5
votes
2answers
173 views

Statistically, what would the average distance of the closest black hole be?

The closest confirmed black hole is several thousand light years away from earth. Our galaxy has about 100 billion stars. I didn't find any reliable information on the black hole count of ratio versus ...
7
votes
1answer
103 views

Is it safer to be near a star or a black hole?

If a star or black hole neared the solar system, which would do the least damage? For the sake of a good comparison, lets assume the candidate star is an "average" 5 solar mass star, and the black ...
8
votes
2answers
173 views

How are black holes doors to other universes?

I'm watching MIT OpenCourseWare lectures on general relativity and not too long into the first lecture the professor stated that the Kerr Black Hole solution allowed for travel between universes. How ...
3
votes
1answer
81 views

What is the optimal escape trajectory from near a black hole?

Consider a space ship that is being drawn closer to a black hole. The crew begins to notice the effects, and discovers that they are nearing the black hole. They then manage to halt their ...
2
votes
2answers
94 views

Why do we think that there is no two-solar-mass black hole?

We think that the mass boundary between neutron stars and stellar mass black holes is around three solar masses. The maximum mass of the neutron stars now is two solar masses and we may find a 2.6 ...
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votes
5answers
580 views

Can we (theoretically) spin the black hole so strong that it will be broken apart by centrifugal force?

I can't imagine the forces involved in black holes' lives. So please, help me to find out, if it is possible or not to destroy black hole in this specific way.
3
votes
1answer
224 views

Would time go by infinitely fast when crossing the event horizon of a black hole?

If you were to fall into a black hole, my understanding is that from your reference point, time would speed up (looking out to the rest of the universe), approaching infinity when approaching the ...
2
votes
2answers
58 views

how to know the nature of the companion in a neutron star binary?

The companion could be a main sequence star, white dwarf, neutron star or black hole. We detected pulsar-pulsar binaryhere several decades ago. But if one of the pulsar does not radiate towards us, ...
6
votes
2answers
206 views

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 ...
3
votes
1answer
69 views

How many black holes exist?

How many black holes exist and what is their distrubtion over mass? There is a list of black holes, but I'm interested in an estimate of all black holes in the visible universe.
1
vote
1answer
118 views

Are neutrinos affected by gravity fields?

Am asking if a neutrino can be pull by the gravity field of a quasar or a black hole, assuming the neutrino have momentum. It could be possible in the that a neutrino can orbit a black hole at an ...
5
votes
3answers
152 views

What shape are black holes theorized to be?

I have always been curious about what black holes (or their event horizons) would look like if we could directly observe them. I notice that they tend to be depicted as flat holes in space but it ...
1
vote
2answers
112 views

How can a Blackhole have mass?

It is said that in Blackhole 100% part of the mass is getting converted into energy. Then how come Blackhole is having mass ?
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2answers
117 views

Is it dark inside a black hole?

Assuming you could be standing inside a black hole, would it be light or dark around you?
6
votes
3answers
230 views

What is a singularity? What is at the center of a black hole? Specifically regarding space-time

So because I can only really think of space-time in 2-dimensions like a sheet of something, my assumptions might be wrong to begin with. I was watching a YouTube video on black-holes and there was a ...
2
votes
1answer
164 views

Black Hole / Hawking Radiation: Why only capture anti-particle?

I may have some specifics wrong here. If so, don't focus on those. Just focus on the general thrust of my question. I "understand" (cough) that particle/anti-particle pairs form spontaneously in ...
1
vote
1answer
83 views

Finding a Kerr Black Holes

I understand that Kerr Black Holes are purely theoretical and have not been found anywhere in the Universe. However, they are theorized for possible means of time travel. I am attempting to prove in ...
4
votes
1answer
124 views

Collision of 2 black holes

There is a large number of visible Supernovas. Each week - about a 20 Supernovas Type 1a around the Universe. Is there collisions of Black Holes? What is this collision called? E.g. 2 black holes ...
5
votes
1answer
93 views

Can a black hole reach a limit where it can no longer attract more matter?

Can a black hole reach a limit where it can no longer attract more matter? If so, what happens with that black hole? Does the black hole die? Does the black hole decrease its size?
4
votes
2answers
109 views

Why does time get slow near a black hole? [closed]

Why exactly does time get slow around a black hole? And does it provide a way to go into the future?
1
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2answers
397 views

Is it possible to create an artificial Black Hole?

I am quite curious about black holes. Once I just thought whether it is possible to create an artificial Black Hole, i.e. an human made black hole. Also explain there formation if it is possible.
2
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2answers
139 views

What is Event Horizon of a Black Hole? [closed]

The boundary of a black hole is said to be surrounded by event horizon - the point of no return! What is its significance in terms of general relativity?
1
vote
1answer
108 views

Black Hole, Object or Portal? [closed]

Some say that a black hole is a rip in space-time, a portal linking two points in the universe as one. How sound is this? I've read that when a giant star collapses, what is left behind (a massive ...
4
votes
2answers
167 views

Do black holes die?

I know of stars actually dying (exploding as a supernova) but I have never heard of what happen to black holes. Do they continue to live forever, waiting there for more matter to absorb? Do they ...
2
votes
1answer
75 views

What does black hole evaporation correspond to in the accelerating universe / black hole analogy?

In the same way, as a black hole emits Hawking radiation corresponding to its temperature $$ T = \frac{\hbar}{r_{BH}} $$ the accelerating universe can be described as all of the stuff falling ...
2
votes
1answer
85 views

Could black holes be creators of dark matter?

At the tremendous forces of gravity inside a black hole, can "matter" be transformed into a more degenerate form; "dark matter" (if that truly what dark matter is)? I know the inside of a black hole ...
4
votes
2answers
118 views

Why one cannot escape from a black hole [duplicate]

The usual explanation is that escape velocity of a black hole is above speed of light, therefore nothing can escape because nothing can move faster than light. This is however a fallacy, because ...
3
votes
2answers
120 views

Are black holes orbiting around each other?

Obviously, bodies with low gravity force orbit around another one with higher gravity force, if they are close enough to each other. Is it true also for objects like black holes? Are they even able ...
2
votes
1answer
115 views

What if the black hole in the center of the galaxy grew faster?

Imagine that hypothetically the black hole in the center of the milky way gradually increased in mass by for example 50% every year. That is exponential increase in mass. Which visual effects would ...