All Questions
24
questions
17
votes
1
answer
1k
views
Can a Kerr black hole become super-extremal?
Let's assume there is a large Kerr black hole, which is almost
extremal and would become extremal with the addition of a small
amount of mass $M$ with spin $J$ to make the final $J=M$.
What if this ...
- 751
7
votes
3
answers
557
views
Why does rotation make black holes smaller?
A non-rotating black hole has a Schwarzchild radius of $2GM/c^2$. A rotating black hole of the same mass has a smaller outer horizon radius, down to a limit of $GM/c^2$ at the fastest possible ...
- 185
3
votes
1
answer
125
views
What is spinning in a spinning black hole? [duplicate]
When a rotating star collapses into a neutron star, the resulting object spins at a huge number of rpm due to its much smaller volume and the conservation of angular momentum. What happens when a ...
- 31
2
votes
3
answers
196
views
Astrophysical vs. Schwarzschild Black Holes
I have heard the idea that real astronomical black holes cannot be called Schwarzschild BHs, not because of rotation but because Schwarzschild contains no mass and is eternal, due to being a ...
- 9,500
1
vote
0
answers
249
views
Does the angular momentum of a Black Hole give insight into a potential solution for the singularity?
Alright so, i want to make one thing clear. I am a bit of a dumbass who watches a lot of PBS Spacetime and read a paper or to on visualising Black Holes. Example image (10k):
I asked a very similar ...
- 308
1
vote
0
answers
35
views
Could the spin of a Black Hole give us insight into the size of the core? [closed]
As we know the conservation of angular momentum seems to be rather true and applies to black holes as well. We know that they spin and we also know the relationship between angular velocity and radius....
- 308
1
vote
1
answer
81
views
Rotating black hole
I know that everything that is shaped from gravity force is rotating, and gravity is a central force. but I want to know how can we detect that a black hole has an angular momentum? By which ...
- 39
0
votes
1
answer
110
views
Speciality of rotating black holes? [closed]
I have read that there are different properties of black hole which are rotating like, they drag the spacetime, with them. Also I read that they have kind of 'ergosphere' along with event horizon. ...
- 2,042
0
votes
1
answer
42
views
What is the physical shape of a rapidly spinning singularity?
Let's say I have a star 20x the mass of the sun. At the end of its life, it collapses into a black hole. Now correct me if I am wrong, but as it collapses it rotational speed dramatically increases ...
- 2,706
-5
votes
1
answer
81
views
What happens if an object spins faster than light? [closed]
Does a star disappears from space time, if it spins faster than light?
- 1
1
vote
0
answers
29
views
How can black hole rotate? [duplicate]
I was reading about black holes and I've found part saying that black hole is a point and anther saying that black hole can rotate. However the points are dimensionless, so they can't rotate - How can ...
- 123
2
votes
2
answers
188
views
Can black hole experiences Coriolis effect?
The weather here are thanks to Earth's rotation, so would there be any coriolis effect however tiny occurs when black hole rotates?
- 13k
0
votes
1
answer
57
views
Black hole and the continuum of laws in normal space
I have heard it said that the laws of physics break down inside a black hole. I find it hard to believe that the law of conservation of angular momentum would not operate inside a black hole. Are some ...
4
votes
1
answer
851
views
What is exactly rotating in a rotating black hole?
I have read this:
https://arxiv.org/abs/gr-qc/9404041
In General Relativity the black hole solutions which have so far been found
form a four parameter family called the generalized Kerr-...
- 29k
3
votes
1
answer
271
views
"Black hole spins at $X$% of the speed of light", what does that mean?
I've seen a few news stories recently (example, example) about some black holes spinning at X% of the speed of light. What does that mean? What exactly is moving at that speed, and with respect to ...
- 33