Linked Questions

2
votes
2answers
890 views

Observer inside event horizon of an extremely large black hole [duplicate]

Imagine a very large black hole, with a mass equal to a large number of galaxies. Assume a space station is in orbit around the black hole some distance from the event horizon at a point A. An ...
2
votes
1answer
227 views

Can you shine a laser on an object that has fallen into a black hole? [duplicate]

I've been having a small back and forth on another website about the nature of objects that fall into black holes. I know that they never reach the event horizon from the perspective of a distant ...
2
votes
0answers
99 views

Falling into the black hole: a picture from the infinite distance [duplicate]

This question was bugging me for many years. Here it was argued that it would take an infinite time for somebody (suppose, an astronaut) to fall into the black hole, given that it is not his time, but ...
39
votes
5answers
5k views

Why is a black hole black?

In general relativity (ignoring Hawking radiation), why is a black hole black? Why nothing, not even light, can escape from inside a black hole? To make the question simpler, say, why is a ...
23
votes
7answers
4k views

Can matter really fall through an event horizon?

This question is closely related to Event horizons without singularities from about a year ago (May 2012), which John Rennie answered nicely and persuasively. My variant of the question is this: ...
15
votes
3answers
4k views

What will the universe look like for anyone falling into a black hole?

I've heard that, from the perspective of an external observer, something falling into a black hole will eventually look "frozen": light waves will move to the infrared and further into lower ...
13
votes
1answer
3k views

Would the inside of a black hole be like a giant mirror?

As any light reflected or emitted from objects inside a black hole (if it is possible to be there) does not leave the event horizon and comes back inside, would it be like seeing yourself? What I ...
13
votes
6answers
768 views

What would be the view like from inside a black hole looking towards the event horizon?

Ignoring the fact that we would be torn apart by gravitational gradient and assuming we get some time to make some observations before hitting singularity, what would we see looking towards the event ...
9
votes
1answer
1k views

Time dilation when falling into black hole

I know that if one astronaut falls into a black hole, then a distant observer will see him take an infinite amount of time to reach the event horizon (provided the observer can see light of ...
1
vote
3answers
2k views

Time paradox inside a black hole

At the event horizon of a black hole, time and the spatial direction toward the center exchange places. The direction inside the black hole from the event horizon to the the singularity in the center ...
4
votes
3answers
1k views

Photons straight into black hole

What happens to a photon shot straight into a black hole? Does it gain infinite momentum before it crosses the horizon? If it has a finite momentum going in, then it would seem that a photon of the ...
1
vote
3answers
515 views

Practical time travel: time dilation above the event horizon [duplicate]

Imagine there is a huge black hole with very small gravity gradient so that one doesn't get killed by spaghettification after even nearing the event horizon. Now imagine a very curious creature ...
3
votes
3answers
518 views

Infalling light signals seen by a free falling observer

In this question/answer Does someone falling into a black hole see the end of the universe?, it is stated that an observer free falling toward/into a black hole will not see the end of the Universe ...
1
vote
2answers
656 views

Do Events Take Place Inside Black Holes?

As you approach a black hole, the universe you observe slows down. When you see someone from outside approaching a black hole, you see how they freeze in time as they get closer and closer to the ...
1
vote
2answers
274 views

Do you see the outside world from inside the black hole (can you see past the horizon from inside it)? [duplicate]

I have read these questions: If you fall in a black hole, when do you go past the event horizon? Can matter really fall through an event horizon? How can anything ever fall into a black hole as ...
4
votes
2answers
152 views

Could all matter in a black hole be actually only on its surface (Schwarzschild radius)?

Layman here, sorry if I miss something obvious. Black hole entropy depends linearly on its surface. If all matter in a black hole would actually be located only on its surface (or very near), wouldn'...
2
votes
3answers
191 views

Does it actually take infinite (observer) time for someone to fall into a black hole?

If you were to watch your friend approach a black hole, I understand that you'd see their clock slow until they appear frozen and redshift within a few seconds. But if you were to detect the ...
1
vote
2answers
231 views

Free falling observer's description of object falling past the event horizon

I know that to a hypothetical observer infinitely far away from the black hole (sometimes known as the Schwarzchild observer), all in falling objects appear to "slow down and asymptotically freeze" at ...
6
votes
0answers
283 views

Aren't black holes required to exist forever in our frame of reference?

I know that for an observer far away, nothing ever crosses a black hole horizon (due to time dilation), while in the frame of reference of a falling observer the horizon is nothing special on its way ...
3
votes
1answer
105 views

Where is the black hole information paradox?

If an object falls into a Schwarzschild black hole and a distant observer watches, they see the object fall slower and slower as it approaches the event horizon, until it is "frozen." (To the observer,...
0
votes
1answer
81 views

Black hole surrounding an object?

When a particle crosses the event horizon of a black hole, at one short moment in time would it appear for that particle as if it was surrounded by a black hole? Regardless of which direction you ...
5
votes
1answer
103 views

Does the maximally-extended Schwarzschild horizon see the entire past of the parallel universe?

I've seen similar discussions for the inner horizons of Kerr and Reissner-Nordstöm metrics, but I've never seen mention for the simple maximally extended Schwarzschild geometry: As an infalling ...
0
votes
1answer
215 views

Falling into a black hole doesn't reveal the future, but does that mean it's not happening?

In a previous answer it was said that you wouldn't see the universe speed up as you fell into a black hole, which I accept as true. However, is being unable to see or interact with the outside ...
-1
votes
1answer
94 views

Does the twin paradox ensure the quantum unitarity near a black hole?

A quantum system of two entangled particles is located near a black hole, particle A is receding from and particle B is moving towards the event horizon. When particle B is crossing the event horizon,...
3
votes
2answers
90 views

Can a black hole event horizon form before the singularity for an outside observer?

This is not a duplicate, my question is not about whether BHs have or don't have a singularity, but my question is whether, because of time dilation, no matter has reached the center and formed a ...
1
vote
0answers
111 views

How can matter reach the singularity of a black hole if time stops at the event horizon? [duplicate]

Black holes are said to be composed of two parts: A singularity at the center, where all the mass of the black hole is condensed in a point of zero volume. A black and empty ball delimited by the ...
1
vote
0answers
68 views

Can matter actually cross the event horizon effectively falling into a Black hole? [duplicate]

The answers I have seen do not take into effect the growth of the radius of the event horizon as significant amounts of matter get close to the existing event horizon. I would have expected that ...
1
vote
0answers
67 views

The nature of event horizons

I am a layman, so I'm not completely up on the latest black hole theories. However, I have been thinking about how an event horizon can be be penetrated by matter outside of the event horizon. Now, ...