All Questions
205
questions
2
votes
4
answers
190
views
Necessity of Singularity in General Relativity
The Schwarzschild solution is the standard example used to describe a black hole, its important points being the event horizon and the central singularity. But this solution is derived by assuming an ...
- 9,500
-1
votes
1
answer
71
views
Can you calculate the radius of a hypothetical singular surface inside a black hole from observing changes to its linear momentum?
Say there is a ball of unknown radius surrounded by a bubble. The ball represents a hypothetical singular surface inside a black hole and the bubble represents the event horizon.
If you threw marbles ...
0
votes
2
answers
105
views
Realistic black holes
If I understand the answers provided in this Link Why singularity in a black hole, and not just "very dense"?
Then the singularity at $r=0$ may just be a mathematical artifact, and may not ...
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
6
votes
2
answers
1k
views
What happens to the ring singularities when two Kerr black holes merge?
Imagine two Kerr black holes with ring singularities oriented in different axes (e.g. one horizontal and the other one vertical). If they merge, what will happen to these singularities? Will they form ...
- 185
3
votes
6
answers
1k
views
Singularity of a black hole: point or solid sphere? [duplicate]
A black hole is defined by its event horizon. The event horizon has a Schwarzschild radius of,
$$r_s=\dfrac{2GM}{c^2}$$
Technically, this means that any body of mass, $M$, with a radius smaller than ...
- 33
1
vote
0
answers
67
views
Types of singularities
I am confused about the types of singularities. According to my limited knowledge there are two types of singularity. One is space like singularity ( a curvature singularity enclosed within a null ...
- 21
0
votes
1
answer
99
views
Range that the Schwarzschild metric is valid
The Schwarzschild metric is the metric calculated from the field equation outside of the black hole. This condition of region (outside of the matter) was the reason why we could use $T_{\mu\nu}=0$.
...
- 311
1
vote
2
answers
173
views
How do black holes infinitely bend space-time when the bending is mass dependent and not density dependent?
According to Einstein, mass bends the fabric of space-time. And nothing in the universe has infinite mass to infinitely bend space-time. So how do remnants of supermassive stars, i.e black holes ...
- 49
0
votes
2
answers
119
views
Why do we defer to GR when describing black holes rather than rely on QM?
This is a broad question but it's well documented that GR and QM are very well tested in their own domains but they conflict around black holes.
Picture a neutron star slowly accreting matter until it'...
-4
votes
1
answer
151
views
If it's a common myth that a black hole contains a singularity, what does a black hole actually (likely) contain?
It's a common myth (especially in popsci) that a black hole contains a singularity. However, I cannot find an explanation for what we think a black hole actually does contain. The best I've seen is &...
- 127
0
votes
1
answer
83
views
How can the distance to the event horizon, as measured by a tape attached to a falling mass, be reconciled with the mass passing through it?
When hovering 2km. above the horizon of a black hole with a mass of the sun, at r=5km., the distance you measure with a measuring tape attached to a mass you throw in the hole will tell you the ...
- 450
0
votes
0
answers
104
views
How far does a particle fall before it hits the singularity of a black hole?
Even though a black hole has a Scwarzschild radius that indicates a finite small distance to the center of the hole, the distance traveled by an infalling particle seems a lot bigger than the ...
- 450
3
votes
0
answers
61
views
Hypothetically, could the interior of a black hole look exactly like the universe that surrounds us?
I do understand that we can't experimentally verify anything we imagine about the interior of a black hole.
If we were to apply what we know about the physics of the observable universe and assume ...
- 33
3
votes
2
answers
266
views
How can we be sure that black hole's singularity is not a missunderstanding? [duplicate]
The Newtonian gravitational potential is given by:
$$\phi=-\dfrac{GM}{r}$$
Which appears in the Schwarzschild metric tensor with a so-called singularity at $r=0$. Nonetheless, I can't get why is it ...
- 495