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4
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2answers
337 views

Black hole formation as seen by a distant observer [duplicate]

Possible Duplicate: How can anything ever fall into a black hole as seen from an outside observer? Is black hole formation observable for a distant observer in finite amount of time? ...
3
votes
1answer
127 views

Are different frequencies of light lensed differently during gravitational lensing a bit like refraction?

So I was wondering about the event horizon on a black hole. And wondering if the point of no return for radio waves vs gamma rays would be different. I guess the logic being, since gamma rays have ...
3
votes
2answers
391 views

What happens to the wavelength/frequency of a photon as it passes through an event horizon?

I've asked a similar question about photons and black holes but wanted to rephrase it more specifically, so here goes... Ever since I learned how a photon's wavelength and frequency are indivisibly ...
-2
votes
1answer
169 views

Way to escape from a black hole

I’ve had a question on WHY a traveler couldn’t “escape” from a black hole under specific conditions (I have an image I'd like to send to clarify, but the website won't let me)> The key is for the ...
0
votes
2answers
104 views

Causal reconnection

Can causally disconnected regions join up again? For example the universe is expanding faster than light creating cosmological horizon, but what if something causes the expansion to slow down and ...
3
votes
2answers
467 views

What do you feel when crossing the event horizon?

I have heard the claim over and over that you won't feel anything when crossing the event horizon as the curvature is not very large. But the fundamental fact remains that information cannot pass ...
6
votes
1answer
348 views

Falling into a black hole

I've heard it mentioned many times that "nothing special" happens for an infalling observer who crosses the event horizon of a black hole, but I've never been completely satisfied with that statement. ...
2
votes
2answers
193 views

event horizons are untraversable by observers far from the collapse?

Consider this a followup question of this one In the classical schwarszchild solution with an eternal black hole, the user falls through the event horizon in finite local time, but this event does ...
3
votes
1answer
127 views

Does cosmic expansion imply the possibility of the universe splitting in half; multiple big-crunches?

There is an event horizon where cosmic expansion leads to superluminal recession speeds for sufficiently distant objects -- the Hubble Volume. 1) Does matter beyond the event horizon affect us ...
2
votes
0answers
217 views

How can things at the event horizon slow down and appear to stop to a remote observer?

So they say the remote observer will never see anything fallen to the black hole, because any object will slow down as it gets closer to the event horizon and eventually stop to stay there forever. Am ...
6
votes
1answer
530 views

Can two particles remain entangled even if one is past the event horizon of a black hole?

Can two particles remain entangled even if one is past the event horizon of a black hole? If both particles are in the black hole? What changes occur when the particle(s) crosses(cross) the event ...
3
votes
2answers
235 views

Direction of Time on Event Horizon

Does the axis of Time point into a black hole or away from? Can you give a reference paper?
8
votes
2answers
615 views

Do apparent event horizons have Hawking radiation?

As I understand it, black holes have an absolute event horizon and an apparent horizon specific an observer. In addition to black holes, an apparent horizon can come from any sustained acceleration. ...
7
votes
3answers
433 views

Horizon and Unruh radiation for a finite period of acceleration

It's a well known fact that an observer that accelerates at a constant rate from $-c$ at past infinity to $+c$ at future infinity sees a horizon in flat Minkowski spacetime. This is easy to see from a ...