All Questions
6
questions
2
votes
2
answers
136
views
What happens if $ a^2 > M^2 $ in Kerr metric?
(Boyer-Lindquist coordinates and $ c = G =1 $ taken)
As I know, line element in Kerr metric $ d s^2 = - \left( 1 - \frac{2Mr}{\rho^2} \right) d t^2 - \frac{4 M a r \sin^2 \theta}{\rho^2} d \phi d t + \...
- 25
1
vote
0
answers
88
views
What specifically prevents the geodesics in Kerr BH from continuing beyond the second world line located inside the inner event horizon?
In a Kerr black hole, the inner event horizon is also called the Cauchy horizon. According to the answer to the question linked here, why are inner horizons Cauchy horizons, the Cauchy horizon only ...
5
votes
2
answers
351
views
How do we determine whether a surface is an event horizon? Exactly what to calculate to do this?
Event horizons play an important role in relativistic astrophysics, especially for black holes, but also for other spacetimes. It is fundamental to be able to determine whether a given surface is an ...
0
votes
2
answers
339
views
Light-like normal vectors
Can someone please show me how to mathematically establish that the normal vector to the event horizon of a Kerr Black Hole is light-like?
- 63
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
0
votes
2
answers
175
views
Why can't a particle rotate opposite to the central mass within the ergosphere?
Wiki says about the Kerr metric:
A moving particle experiences a positive proper time along its worldline, its path through spacetime. However, this is impossible within the ergosphere, where $g_{...
- 982