All Questions
73
questions
0
votes
0
answers
72
views
Where is the mass in a Black Hole without a "central" curvature singularity?
Not all black holes have a curvature singularity at their center (an example). But in principle, I thought that the curvature singularity was a direct result of the fact that the mass is concentrated ...
- 770
26
votes
10
answers
13k
views
How do black holes move if they are just regions in spacetime?
If black holes are just regions of spacetime, how can black holes even move? When matter moves through spacetime, it bends the spacetime around it, but if black holes are just regions of spacetime, ...
- 403
2
votes
0
answers
40
views
Calculating Gaussian Curvature for metric
I am trying to calculate Gaussian curvature of an optical metric
$$
d \sigma^2=\frac{r\left(\omega_{\infty}^2-\omega_e^2\right)+2 m \omega_e^2}{(r-2 m) \omega_{\infty}^2}\left(\frac{d r^2}{1-\frac{2 m}...
- 21
1
vote
2
answers
115
views
Is the curvature so extreme at the event horizon, that you could see curved laser beams?
I have read this:
Because the spacetime curvature at the horizon is so great that there is no light-like world line the extends beyond the horizon.
Why does time stop in black holes?
If the ...
- 29k
6
votes
1
answer
262
views
How to find that there is a conical singularity in the BTZ black hole?
Considering a non-rotating and non-charged 2+1 dimensional black hole, known as the BTZ black hole which obtained by adding a negative cosmological constant $\Lambda=-\frac{1}{l^2},l\ne0$ to the ...
1
vote
2
answers
173
views
How do black holes infinitely bend space-time when the bending is mass dependent and not density dependent?
According to Einstein, mass bends the fabric of space-time. And nothing in the universe has infinite mass to infinitely bend space-time. So how do remnants of supermassive stars, i.e black holes ...
- 49
0
votes
1
answer
102
views
Flat space between colliding black holes
When 2 black holes approach each other, they both bend space in an opposite direction. There must always be a flat space between 2 colliding black holes.
However, I heard that they actually merge, ...
- 187
-4
votes
2
answers
108
views
Would continuously increasing curvature of space explain seeming expansion of the universe? [closed]
Could expanding universe phenomenon be explained by slowly but continuously increasing curvature of space around masses like galaxies and galaxy clusters? In other words, I am curious whether the ...
- 113
4
votes
0
answers
44
views
Eigenvalues of the geodesic deviation equation, curvature invariants, and singularities
The geodesic deviation equation tells us what tidal forces freely falling observers experience in a local Lorentz reference frame. The tidal deformation tensor is
$$E^{\alpha}_{\gamma}=R^{\alpha}_{\...
- 572
0
votes
0
answers
40
views
Can there be black holes in a 1+1D spacetime? [duplicate]
In 2D Einstein tensor is always zero, that means no mass (or cosmological constant or other stress energy tensor component) is allowed. Nevertheless, we can get nonzero Riemann, even nonzero Ricci ...
- 1,161
5
votes
2
answers
221
views
Meaning of zeros in the metric tensor
I'm trying to find the $g_{0i}$ components of the metric I mentioned here, but it has turned extremely difficult. My current strategy is to equate Ricci tensor components gotten from the Christoffel ...
- 495
0
votes
2
answers
188
views
Curvature of space in a black hole
This is a very simplistic view from an interested structural design engineer (retired).
Mass curves space. Taking the case of a sphere of uniform density the point at which you have as much mass ...
1
vote
1
answer
496
views
How do I use the Schwarzschild metric to calculate space curvature and time curvature seperately?
I want to understand the math behind the idea that around Earth time dilation accounts for 99.99% of gravity, while around a black hole it only accounts for 50% of gravity while space curvature ...
- 4,783
0
votes
1
answer
85
views
Is there no curvature due to mass when travelling along a sphere outside a black hole?
I'm trying to do actual Schwarzschild Metric calculations. In looking at this video Schwarzschild Proper Distance at 1:20 he shows the calculation for moving directly outward on a radius from the ...
- 4,783
0
votes
2
answers
1k
views
For the Schwarzschild metric, are the values of the Ricci tensor and Ricci scalars always zero? [duplicate]
If we use the Schwarzschild metric to solve the Einstein field equations, would the values of the Ricci tensor and scalars always be zero?
- 625