Linked Questions

93
votes
14answers
22k views

How can anything ever fall into a black hole as seen from an outside observer?

The event horizon of a black hole is where gravity is such that not even light can escape. This is also the point I understand that according to Einstein time dilation will be infinite for a far-away-...
5
votes
1answer
671 views

Would dense matter around a black hole event horizon eventually form a secondary black hole? [duplicate]

Possible Duplicate: Black hole formation as seen by a distant observer Given that matter can never cross the event horizon of a black hole (from an external observer point of view), if a black ...
1
vote
1answer
136 views

Can we observe a star collapse into a black hole? [duplicate]

Let's say that I happen by a star that has just burned out and is collasping into a black hole. I seat at infinity to watch it as a Schwarzschild observer. Will I ever see the black hole collapse into ...
3
votes
0answers
76 views

Can a black hole actually grow, from the point of view of a distant observer? [duplicate]

Possible Duplicate: Black hole formation as seen by a distant observer I've read in several places that from the PoV of a distant observer it will take an infinite amount of time for new matter ...
1
vote
0answers
34 views

Does a black hole ever fully form to an outside observer? [duplicate]

According to general relativity, I had understood that time appears to slow down when looking into high gravitational fields from afar, so that as a black hole forms, the light from a collapsing star ...
58
votes
10answers
8k views

Can black holes form in a finite amount of time?

One thing I know about black holes is that an object gets closer to the event horizon, gravitation time dilation make it move more slower from an outside perspective, so that it looks like it take an ...
3
votes
2answers
1k views

Does a black hole have enough time to actually form a singularity?

I am trying to wrap my head around black holes, singularties and hawking radiation. Physics.se contains many intresting questions and answers, but from none I could so far read about the interaction ...
2
votes
3answers
289 views

How can classical black holes even exist?

I am not asking about the event horizon, but the actual black hole itself and I am asking this question based on the following thought experiment: Imagine the hypothetical process where you have a ...
0
votes
1answer
289 views

How can black hole get mass if nothing can pass its event horizon? [duplicate]

External observer will never see any mass crossing event horizon - any object near it would appear frozen, red-shifted and then disappearing. In this case - how black hole can possibly get any mass ...
1
vote
0answers
132 views

Do black holes exist? [duplicate]

Do black holes exist from our point of reference? From our point of reference nothing actually goes inside the event horizon right? So is there anything inside the event horizon from our reference? If ...
1
vote
1answer
83 views

How does a distant observer see matters that “form” an initial black hole?

I did see Can black holes form in a finite amount of time? but it does not seem to discuss how a distant observer would see evolution of collapsing matters that form a black hole. Does it view these ...
2
votes
0answers
41 views

How can non-infinitesimal Black holes form in finite time for a distant observer? [duplicate]

Say you are on earth observing a staring hypernova at safe distance from earth. Now as soon as the core collapses to its Schwarzschild radius the singularity would come into existence and so would ...