All Questions
Tagged with relative-motion general-relativity
33
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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 ...
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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 ...
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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 ...
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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 ...
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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 $...
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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 ...
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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 ...
user319766
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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 ...
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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:
$$ \...
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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 ...
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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 ...
- 159
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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 ...
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Non-uniform relative motion between inertial reference frames?
I have the following doubt: let person A be in free fall being gravitationally attracted towards a massive body M. Suppose then that person B is completely isolated in space and in particular very far ...
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Does Special Relativity Imply Multiple Realities?
Thank you for reading. Before you answer my question, I feel I need to let you know that I'm still a beginner in special relativity...so the more thorough the answer, the better. Thank you! Alright, ...
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Relativity and electromagnetic field
I have a question regarding Misner, Charles W.; Thorne, Kip S.; Wheeler, John Archibald (1973), Gravitation ISBN 978-0-7167-0344-0. It is a book about Einstein's theory of gravitation.
At the page 79,...
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Role of motion in experimental results
This page contains:"If you are in a closed room on a ship sailing at a constant speed and the ride is perfectly smooth...[t]here’s no physical experiment you could conduct to tell whether you’re ...
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Detecting external 'forces' in an inertial frame
Disclaimer: Science noob here, I may not use all terms correctly.
I've read somewhere of the following situation: An observer is inside a room (elevator) with no ...
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Are there local coordinates for Schwarzchild spacetime?
In the Schwarzchild metric, $t$ is the time on the clock of an observer at infinity, and $r$ is the related to the area of a sphere by $A=4\pi r^2$. Are there more physical coordinates one could use, ...
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Does time really pass slower near massive objects or only if there is motion of a reference frame relative to it?
Question is fairly self explanatory.
From relativity, we hear that the Earth distorts spacetime making the time pass slower near it in respect to an observer in outer space. My question is, if the ...
user137288
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Accelerating towards a photon
What will be the relative speed and motion between me and a photon if I would have accelerated towards a photon that is moving away from me?
Would it get away from at a slower velocity relative to me, ...
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How relativity works for static object and distances
Suppose there are two stations A and B. There is an observer standing on station B. A train starts from station A and moves towards B at a constant speed V. Relative to the train speed of the observer ...
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Dark matter and relativistic mass change [duplicate]
Could the requirement of a dark matter for the missing mass in the universe simply be explained by objects having high relativistic mass change with respect to other objects?
If this is not the case, ...
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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 ...
user32023
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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 \;\...
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Disappearing galaxies [duplicate]
According to the cosmological model of the expanding universe, the distant (diametrally opposite) galaxies have bigger and bigger relative comoving speed, and this speed (which is not a relative speed ...
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Is General Relativity compatible with relative speeds bigger than $c$ between two inertial frames?
My question is motivated by a remark done by Tegmark in his book "Our Mathematical Universe". He says that GRT does not prove that relative speeds between material points are always smaller than c. It ...
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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 ...
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Does a body curve spacetime at higher velocities? [duplicate]
Suppose we have two objects where the distance over time decreases. Now, as I understand it, general relativity says that we can observe the Universe from the perspective of both objects an get a ...
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Foucault pendulum explanation, rotating earth or rotating universe?
If we start from the assumption that all frames of reference are valid for describing motion, how can a foucault pendulum either prove or disprove that the earth rotates or is stationary?
Couldn't ...
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Are there any good references on the "gravitational" curvature of spacetime of a moving mass being distorted due to special relativity?
In this Wikipedia paragraph suggesting an explanation for the phenomenon of inertia, it claims:
Another physicist, Vern Smalley, has derived the Lorentz transformation for mass by assuming that the ...
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Evidence for expansion of space [duplicate]
If I understand correctly, Einstein's theory of General Relativity predicted the expansion of space itself, and Hubble confirmed this prediction by observing the red shift of receding galaxies.
I ...
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Space Expansion vs. Relative Motion
Given 2 objects moving at some velocity $v$ relative to one another, is it possible to determine whether they are moving or whether the space between them is expanding?
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Galilean transformation in relativity
Assume flat spacetime in a general relativistic framework (or special relativity for that matter) and two observers $A$ and $B$, with non-vanishing velocity relative to each other. We know that they ...
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