All Questions
20
questions
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
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
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 ...
0
votes
2
answers
236
views
Why are distances to event horizons linear with mass when gravitational effects fall off as $1/r^2$?
Black holes' gravitational effects fall off as $1/r^2$, but their event horizon grows linearly with increasing mass. $R$ (event horizon) grows the same rate as $M$ (mass of black hole). Okay lets ...
0
votes
2
answers
133
views
What would happen to a long ruler in a strong gravitational field?
So, let's say that we have an incredibly long, virtually indestructible ruler. We have advanced enough to move it wherever we want. Let's also say that we have another, identical ruler of the same ...
- 365
1
vote
1
answer
187
views
Schwarzschild geometry
In the text "Exploring Black Holes" by Taylor ,Wheeler I came across the following thought experiment
"We consider two imaginary concentric spherical shells and suppose we measure the &...
0
votes
1
answer
134
views
Why spacetime fabric don't tears due to mass of heavy black hole?
In GR, All objects create curvatures in the space-time fabric. Why space-time fabric doesn't tear due to the mass of a heavy black hole? What is it made of?
1
vote
1
answer
250
views
Make $\pi = 3$ again [closed]
The value of $\pi$, or the circumference divided by the diameter of a circle, is known with absurd precision, but I want it to be 3.
The circumference around a black hole outside the Schwarzschild ...
- 2,075
2
votes
1
answer
208
views
Is it accurate to say space moves because spacetime is curved?
I've learned from PBS Space Time videos that space rushes into a black hole's event horizon at the speed of light. I'm trying to square this with the analogy of stretched rubber sheet everyone uses; ...
- 384
2
votes
2
answers
113
views
Regarding 'The Science of Interstellar', space warping section
While reading Thorne's 'The Science of Interstellar', I came across this piece of information:
'Now, the Sun’s equatorial plane divides space into two identical halves, that above the plane and ...
- 123
0
votes
1
answer
173
views
Are the space and time axes of Schwarzschild metric uncurved?
Schwarzschild metric is commonly considered as an expression of curved spacetime:
$$ \mathrm ds^2 = -\left(1 - \frac{2GM}{c^2 r}\right) c^2~\mathrm dt^2 + \frac{1}{1 - \frac{2GM}{c^2 r} }~\mathrm dr^...
- 3,155
2
votes
2
answers
102
views
Light escaping from stars despite their mass?
"Light is deflected by powerful gravity, not because of its mass (light has no mass) but because gravity has curved the space that light travels through."
If the Mass of the Sun is so great, how is ...
- 23
1
vote
1
answer
394
views
Inside a black hole can a person ‘touch’ space?
Take a look at this picture
Now if a person falls inside a black hole and he stretches his arms outside. At some point the region which is red in colour will exactly match the width of the person who ...
- 1,770
1
vote
0
answers
92
views
Effect of theoretically infinitely heavy body on spacetime [closed]
What is the effect of theoretically infinitely heavy massive body on spacetime? And what happens when it moves and/or rotates/spins along a path?
5
votes
2
answers
883
views
How to derive exterior and/or interior Schwarzschild solution using Feynman excess radius equation?
Feynman excess radius equation for a uniformly dense spherical body is
$R-\sqrt{\frac{A}{4\pi } } = \frac{G}{3c^{2}} M$
Where $R$ is the radius directly measured by digging a hole in the body, $ A $ ...
- 2,326