# Tag Info

### Necessity of Singularity in General Relativity

According to Thorne and Susskind, the fact that a black hole's mass is distributed as a 2-dimensional surface (the event horizon), and not a volume, indicates that the black hole has no interior. You ...

### Necessity of Singularity in General Relativity

To solve the GR equations at singularity you need to divide by zero. You can't divide by zero. This means that GR doesn't make predictions about what happens there. There is no solution to equations ...

### Necessity of Singularity in General Relativity

Well the famous singularity theorems show (very very roughly speaking) that in the theory of classical GR, collapse beyond horizon implies a singularity. Classical GR is not the true theory of physics,...
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1 vote

### Necessity of Singularity in General Relativity

What is it that preludes the predicted field, even at $r<r_{Schwarzschild}$, from simply terminating at the surface of a collapsar of dense matter, and taking some other form inside it? This is ...
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### Why singularity in a black hole, and not just "very dense"?

Is it not possible that, like snowflakes, no 2 black holes are exactly identical and each black hole should be treated as a unique set of parameters. Black hole A uses 30% of these rules 30% of those ...
1 vote

### Hawking Temperature of the BTZ Black Hole

Another option for finding the Hawking temperature of the BTZ black hole is by the formalism of the surface gravity $\kappa$ which connected to the Hawking temperature via: $$T_H=\frac{\kappa}{2\pi}$$ ...

### Can black holes fully merge, according to a distant observer?

Black hole forms once there is sufficient mass in a volume of space. Once you get close enough to a black hole according to distant observer, it's event horizon will expand and swallow you before you ...

### Can you calculate the radius of a hypothetical singular surface inside a black hole from observing changes to its linear momentum?

No, because as an observer outside the event horizon, you will never be able to see an object cross the event horizon. (See This post)

### Is the size of a black hole singularity smaller than a fundamental particle?

We know that black hole is infinitely densed. More exactly: The theory of general relativity predicts that the center of a black hole is infinitely dense. This theory predicts very well everything ...
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### Is the size of a black hole singularity smaller than a fundamental particle?

While @paulina's answer: we don't know is correct, because quantum gravity is not understood, I'll answer for a classical Schwarzschild blackhole as described by Kip Thorne. The size is zero, however ...
• 35.4k
Accepted

### Is the size of a black hole singularity smaller than a fundamental particle?

The very short answer to this is: We have no idea. General relativity predicts that the singularity of a Schwarzschild black hole (which I assume is what you mean by "actual black hole") is ...
• 1,897

### Does black hole formation contradict the Pauli exclusion principle?

In actuality, there is no such thing as this so called singularity... It's a convenient mathematical invention to represent something of which we understand very little. Although quantum physics can ...
Accepted

### Memory effects from black hole migration in the early universe

I can look at the black hole after some time when it has moved away a little bit. Now the region of space that was previously inaccessible to me is accessible. I think your misconception is thinking ...
• 56.4k
Accepted

### Is the information or energy in a black hole converted to another form of energy during decay of Hawking radiation?

If a large amount of non-rotating thermal energy collapses into itself, the result is a non-rotating black hole, whose energy is thermal energy. If one unit of thermal energy is conducted away from ...
• 2,083
Accepted

### Extreme Mass Ratio Inspirals and GWs cycles

There is no well established taxonomy of dividing the inspiral into "late" and "early" parts. When people do talk about the "late inspiral" they mean "that part of ...
• 12.5k
1 vote

### WKB Approximation of the Quasinormal Mode Spectrum of the Poschl-Teller (PT) Potential

Schrödinger operators with reflectionless Pöschl-Teller potentials arise in the study of SUSY chains of one-dimensional non-linear field theories labeled by $N$. The two first members of the family ...
• 21

### Binary black hole merging condition

The critical impact parameter $b_{\rm crit}(v)$ depends on the highly non-linear general relativistic interaction of the two black holes. The only way we currently have to address this question is ...
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### Black Hole Formation -- How Can an Event Horizon be Observed to Grow?

It's the total mass that counts and we can indirectly observe a black hole growing through changes in the behaviour of objects surrounding it, those affected by its gravity and rotation. Naturally, ...
• 740

### How come the magnetic field disappears when a neutron star becomes a black hole, while the rotation remains?

Árpád Szendrei asked: "How come the magnetic field disappears when a neutron star becomes a black hole?" If a net electric charge remains, the star would collapse to a Kerr Newman black ...
• 12.4k