All Questions
Tagged with relative-motion general-relativity
33
questions
11
votes
3
answers
7k
views
How can you accelerate without moving?
I know this question has been asked in other forms, generally regarding the balance of forces. This time I want to focus on motion. I've got a laser accelerometer on my desk. It tells me that I'm ...
- 109
1
vote
0
answers
74
views
Coordinate transformation and absolute motion in general relativity
In special relativity, all motion is relative. But in the presence of black hole, all motion is with respect to black hole. The curvature of spacetime depends on how far we are away from the black ...
- 134
-1
votes
3
answers
127
views
Any experiment for relative simultaneity?
Any introduction of relative simultaneity usually is like this :
Alice on a train car shines two beams of light towards both ends where two clock are. She sees both clocks see the light at the same ...
- 84
5
votes
0
answers
173
views
Sum of geodesic deviation around a triangle in curved spacetime?
So I was pondering about geodesic deviations and I'm confused about the following. Let's say I have $3$ geodesics $\gamma_1(t)$ , $\gamma_2(t)$ and $\gamma_3(t)$. I introduce a parameter $s$ such that ...
- 1,389
1
vote
1
answer
142
views
Relative velocity and proper time derivative of geodesic deviation?
From wiki
To quantify geodesic deviation, one begins by setting up a family of closely spaced geodesics indexed by a continuous variable s and parametrized by an affine parameter $\tau$. That is, for ...
- 207k
0
votes
1
answer
67
views
If the escape velocity for a body that is very close to a BH is near $c$ but not $c$ can it move away a little bit before it falls inside the BH?
The escape velocity from a common gravtational attractor means that a body lounched away from the attractor will never turn back. But in the case of a BH at the event horizon this escape velocity is $...
- 207k
118
votes
13
answers
42k
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If all motion is relative, how does light have a finite speed?
I've often heard that Einstein shattered the notion of absolute motion (i.e. all things move relative to one another) and that he established the speed of light as being absolute. That sounds ...
- 107
2
votes
3
answers
553
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If I accelerate through space, can I say all stars gain kinetic energy?
Suppose I accelerate through empty space. Say all stars are small heavy marbles I can use to do work with by means of their velocity. Say I can let them smash into some generator that turns their ...
- 26.4k
0
votes
2
answers
140
views
Is there any physical experiment that could tell us which object is moving to the other?
Imagine in empty space there are two objects in where one of them is moving to the other. How we can know which one is moving to the other? If there is an experiment that could tell us, would this ...
- 207k
16
votes
10
answers
5k
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Why do bodies traveling at constant velocity experience the same physics?
I am new to special relativity. I don't have a background in physics.
I was reading Brian Green's The Elegant Universe and got hung up on an example.
In fact, Einstein realized that the principle of ...
- 38.3k
7
votes
1
answer
2k
views
What is my acceleration in my own frame?
This is , I suppose not a good question , but I think I am missing something which confuses me in this question.
So my question is:
Velocity is relative. So suppose a car is moving at a speed $200 \;\...
- 12.1k
7
votes
1
answer
419
views
How to calculate relative velocity in curved spacetime?
Is there a nice geometric way to calculate relative velocity in curved space time? I'm looking from something similar to how the separation vector $n$ between $2$ neighboring geodesics obey:
$$ \...
- 207k
2
votes
1
answer
66
views
How would we know whether a object is moving in deep space?
In deep space, there isn't anything we can compare our position with (According to my knowledge). In other words, we won't be able to define an origin so how would we know whether we are in motion or ...
- 73.7k
1
vote
1
answer
169
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Acceleration and geodesics in General Relativity
Consider this situation:
A) An aeroplane travels a distance from point A to point B which are located on the opposite sides of the Earth. The aeroplane has taken the shortest possible distance to ...
- 410
2
votes
1
answer
254
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Does General Relativity actually satisfy the General Principle of Relativity?
The “General Principle of Relativity” being “All systems of reference are equivalent with respect to the formulation of the fundamental laws of physics”. To my knowledge, this is related historically ...
- 11.7k