Linked Questions

0
votes
1answer
54 views

Black Holes and Time [duplicate]

My understanding is that if I am outside a black hole and watch something fall in, the object will appear to slow down and will never actually get sucked in. So how can we ever get a black hole if ...
1
vote
0answers
44 views

Thoughts on Black Holes [duplicate]

Given that time slows to a stand-still at the event horizon of a Black Hole, how long would it take a black hole to form, from the perspective of an outside observer? It would seem, as a massive star ...
1
vote
0answers
34 views

Black Holes should take infinite time to form with the increase in mass to form one [duplicate]

How can black hole form because as the density begins to increase gravity also start to increase and time starts to slow. wouldn't it take infinite time to form a black hole. how can anything fall ...
0
votes
0answers
32 views

Does black hole contain anything? [duplicate]

Suppose an object A is traveling towards black hole. For an observer outside it looks like A almost reached even horizon and is still trying to reach it. So from point of view of an observer all the ...
1
vote
0answers
26 views

Can one observe a blackhole grow from outside its event horizon? [duplicate]

For an observer outside Black hole's event horizon nothing ever falls into the black hole . So if the observer waits for an eternity outside a super massive blackhole feeding on gas , will the ...
1
vote
0answers
25 views

How can a black hole grow, as seen by an outside observer? [duplicate]

How can a black hole grow in mass, if it takes an infinite time to cross the event horizon,  for matter approaching the black hole (as seen from an outside observer far from the black hole)? To make ...
0
votes
0answers
22 views

Infinity at event horizon boundary [duplicate]

It has been repeatedly explained to me that from the perspective of an outside observer a particle takes "infinite time" to cross the event horizon of a black hole. Also, according to these ...
399
votes
16answers
40k views

How does gravity escape a black hole?

My understanding is that light can not escape from within a black hole (within the event horizon). I've also heard that information cannot propagate faster than the speed of light. It would seem to ...
64
votes
10answers
9k 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 ...
36
votes
9answers
8k views

Does any particle ever reach any singularity inside the black hole?

I am not a professional physicist, so I may say something rubbish in here, but this question has always popped in my mind every time I read or hear anyone speak of particles hitting singularities and "...
19
votes
10answers
5k views

How does light behave within a black hole's event horizon?

If the event horizon of a black hole is the distance from the center from within which light cannot escape, imagine a person with a flashlight falls into the black hole. He points his flashlight in 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: ...
22
votes
3answers
918 views

Black hole no-hair theorems vs. entropy and surface area

I was revisiting some old popular science books a while ago and two statements struck me as incompatible. No-hair theorems: a black hole is fully-described by just a few numbers (mass, spin etc) ...
19
votes
3answers
2k views

So Black Holes Actually Merge! In 1/5th of a Second - How?

I've read a lot of conflicting answers in these forums. However, today saw the awesome announcement of gravitational waves. Two black holes merged: http://www.slate.com/blogs/bad_astronomy/2016/02/11/...
16
votes
4answers
2k views

Event horizons without singularities

Someone answered this question by saying that black hole entropy conditions and no-hair theorems are asymptotic in nature -- the equations give an ideal solution which is approached quickly but never ...

15 30 50 per page