All Questions
10
questions
1
vote
1
answer
72
views
Why are there two interior regions in this diagram?
Why are there two interior regions in this diagram? There seems to be two inner horizons, and two wormhole regions.
Where do the two such regions comes from? What determines which reason someone falls ...
- 2,908
7
votes
1
answer
358
views
Why is Kerr Spacetime unstable?
How do we know from the Kerr Metric that it is unstable near the Cauchy Horizon? What causes this unstability?
- 1,161
2
votes
1
answer
228
views
What happens to the ergospheres of two colliding black holes, right before collision?
Let's assume we have two black holes with equal mass. They move towards each other, each heading towards the center of the other black hole. Both black holes rotate with equal speed. What happens to a ...
- 163
10
votes
4
answers
999
views
Does the twist of spacetime by a black hole increase over time?
From the Wikipedia page about Ergospheres:
As a black hole rotates, it twists spacetime in the direction of the rotation...
Does this "twisting up spacetime" add up over time in any ...
- 163
2
votes
1
answer
1k
views
Event horizon of a rotating black hole
For a non-rotating black hole, Schwarzschild radius itself forms the event horizon, but how do we find the event horizon of a rotating Kerr black hole?
user301349
3
votes
2
answers
2k
views
What's the inner ergosphere in a Kerr black hole?
(My book uses the notation "ergosphere" as the hypersurface of static limit, "ergoregion" as the hypervolume within.)
Studying the Kerr BH, I've come to the part about horizons and ...
- 5,931
2
votes
2
answers
537
views
Gravitational Redshift in Kerr Spacetime
Well, suppose then Schwarschild black holes. Following the $[1]$, we have the redshift factor:
$$d\tau = \sqrt{1-\frac{2M}{r}}dt. \tag{1}$$
This factor have an physical interpretation to be the ...
- 3,085
21
votes
3
answers
6k
views
How does the Penrose diagram for a spinning black hole differ in realistic scenarios (formed by stellar collapse)?
The Penrose diagram for a non-spinning Schwarzschild black hole is
Notably, there is a second universe "on the other side" of the black hole. However, actual black holes form by stellar collapse, and ...
- 11.6k
4
votes
2
answers
343
views
Kerr Black hole EH and Ergosphere embedding
Goodmorning everyone. I would like to share with you a question that has been gripping me for some time, but which I have never been able to give a convincing answer. When representing the ergosphere ...
6
votes
2
answers
2k
views
Closed timelike curves in the Kerr metric
I just read in Landau-Lifshitz that the Kerr metric admits closed timelike curves in the region $r \in (0, r_{hor})$ where $r_{hor}$ is the event-horizon ( I am talking about the case $|M|>|a|$ (...
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