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7 votes
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 ...
paulina's user avatar
  • 1,906
6 votes

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 ...
JEB's user avatar
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5 votes

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 ...
Thomas Fritsch's user avatar
2 votes
Accepted

Two contradictory derivations of Killing equation

As an overall comment, I stress that conservation of $Q$ is valid for the Killing vector $\xi$ if the considered curve is a geodesic. Let us come to the issue. First of all, generally speaking, the ...
Valter Moretti's user avatar
2 votes

Two contradictory derivations of Killing equation

Both approaches are fine. In the first approach, the analysis is done at the coordinate/component level of the equations. Simply asking the question how does $Q$ very with $\tau$ if we write ...
TimRias's user avatar
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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: $$T_H=\frac{\kappa}{2\pi}$$ ...
Daniel Vainshtein's user avatar
1 vote
Accepted

Cause of Coordinate Acceleration in Free Fall

The acceleration on a particle following a geodesic is defined by the Christoffel symbols which are in turn defined in terms of the metric. More properly, all inertially-moving objects not affected by ...
controlgroup's user avatar
1 vote

Trying to understand a visualization of contravariant and covariant bases

Given the metric tensor for the basis vectors $$A = \begin{bmatrix}\mathbf e_1 \cdot \mathbf e_1 & \mathbf e_1 \cdot \mathbf e_2 \\ \mathbf e_2 \cdot \mathbf e_1 & \mathbf e_2 \cdot \mathbf ...
Antoni Parellada's user avatar
1 vote

Two contradictory derivations of Killing equation

I think the problem lies in the notation. I guess Tong is treating the components $\xi_\mu$ as scalars for which we have $\frac{\mathrm{d}}{\mathrm{d}\tau}=u^\alpha\partial_\alpha$. And the ...
Silas's user avatar
  • 426
1 vote

What is the gravitational field of a hole in an infinite perfect crystal?

... overdensity attracts underdensity and underdensity repels overdensity ... Yes, in an empty universe a pair of matched positive and negative masses initially at rest would be self-accelerating ...
A.V.S.'s user avatar
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