All Questions
10
questions
2
votes
2
answers
917
views
Theoretically, can perfectly flat space exist in the universe?
According to general relativity, mass and energy cause the curvature of space. To have perfectly flat space, there must be a completely empty vacuum state with no mass or energy.
Theoretically, is it ...
- 305
2
votes
7
answers
1k
views
I can't wrap my head around the idea of matter interacting with spacetime. How is the interaction taking place? [closed]
I have tried Googling this for a long time. I have read many forums on this. But still, it doesn't make sense.
General relativity says that space-time is bent/changes when a massive object is there. ...
13
votes
3
answers
2k
views
Does vacuum spacetime have an inherent curvature?
I am a complete novice in physics beyond the high school level, so please excuse anything wrong in my question.
So I have recently read that according to General Relativity, the presence of mass in ...
- 141
-3
votes
1
answer
106
views
How do galaxies move through space-time?
If we assume that galaxies only consist of planets, stars, and space, then how do galaxies move through space?
How do you move empty space, or is it that space remains same, but the planets, stars, ...
0
votes
1
answer
559
views
Curvature of space without mass or energy [duplicate]
Are there solutions of Einstein's equation
$$ R_{i,k}=0 $$
which imply there are 'curvature' without matter or energy?
For example, space is curved but there are no matter or any energy there so an ...
- 4,747
3
votes
2
answers
245
views
Einstein field equation specific solution
Do Einstein's field equations admit a solution such that spacetime was empty in the past of a hypersurface of constant time say $t =0$, but in the future there exists a non-vanishing energy momentum-...
- 1,124
1
vote
4
answers
131
views
Can spacetime be curved even in absence of any source? [duplicate]
Einstein's equation in absense of any source (i.e., $T_{ab}=0$) $$R_{ab}-\frac{1}{2}g_{ab}R=0$$ has the solution $$R_{ab}=0.$$
But I think $R_{ab}=0$ does not imply that all components of the Riemann-...
- 11.7k
5
votes
2
answers
2k
views
Does a vacuum solution to the Einstein equation imply flat spacetime?
I have read that a solution to the vacuum Einstein equation has a vanishing Einstein tensor, and therefore a vanishing stress-energy tensor. This means that there is no matter to generate spacetime ...
- 661
1
vote
0
answers
55
views
Einstein equation outside of the source
When solving Einstein equation outside the source it is assumed that we have $R=0$ where $R$ is Ricci tensor. But if we have as a source Earth and for example, a black hole, how can this equation ...
- 1,803
3
votes
3
answers
815
views
If all matter were removed from space-time, what would be remaining?
I would like to gain an understanding of the nature of the characteristics of space, as described in Einstein's theories. I appreciate that an answer using the language of mathematics is probably most ...
