All Questions
Tagged with special-relativity observers
64
questions with no upvoted or accepted answers
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Axiomatization of SR: can we replace light rays with timelike world-lines?
If I eliminate a lot of details and just sketch the general ideas, then a common way of presenting SR is this:
Axiom 1: Clocks exist.
Axiom 2: Light rays exist.
This is the approach followed in, e.g....
user4552
3
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Does an object travelling at speeds approaching $c$ observe an increase in the expansion rate of the universe?
According to the theory of special relativity as an object approaches light speed it experiences length contraction. This means that the distance it observes between it and it's destination reduces as ...
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Can you experience length contraction in an accelerating reference frame?
Imagine I am floating in space some large distance X above a neutron star or high mass object and I am using rocket boosters to stay stationary relative to the object. Assume no other forces acting on ...
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Special Relativity, thought experiment from Sagan's "Cosmos"
Here's a small paragraph from Carl Sagan's "Cosmos" describing what a person travelling near the speed of light would observe (as a thought experiment):
"...As your speed increases, ...
- 95
2
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2
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Is there a connection between the energy distribution and time dilation?
Can anyone please help me understand what is descibed bellow?
Scenario 1.
We have a pair of atomic clocks. Let's call them clock A and clock B. We switch both of them on at the same time. Clock A ...
2
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5
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Derivation of the length-contraction formula
i saw the derivation of the length contraction and it goes like this:
what i dont understand is why does interval between the photon striking and coming back have to be compared? why can't I simply ...
- 1,581
2
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3
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Quick check: relativity, rockets, clocks and the equivalence principle
One common thought experiment that introduces relativity on gravitational fields is the "clocks on an accelerating rocket":
Paraphrasing Mr. Feynman:
Suppose a rocket, with two clocks, one on each ...
user133382
1
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0
answers
42
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Radiation from a stationary charge relative to earth for a free falling observer
It is my understanding that if we have a charge at rest on earth, a free falling observer will see it radiating, as the charge is in an accelerated frame of reference. This observer can in principle ...
- 795
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1
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How would a spacecraft travelling near light speed say 0.9c compensate for time dilation in radio communication from spacecraft to earth?
For a spacecraft travelling at 0.9 c for 5 seconds, only 5 seconds would have passed for an observer on Aircraft, while 26.31 second would pass for a stationary observer watching from Earth.
In a ...
1
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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 ...
- 134
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1
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129
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Unsure about the proper use of Lorentz transform
I'm not very comfortable with handling Lorentz transformations and I often have doubts...
Consider for example the following situation, illustrated by the diagram below:
A rod of length $L$ is placed ...
- 187
1
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106
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Energy is the time component of 4-momentum in SR: Proof as per R. Wald's book
This is an excerpt fom R. Wald's book on General Relativity (page 61). I'm not able to understand how he deduces that $E$ must be the time component of $p^a$ with only the assertions made before this ...
- 107
1
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2
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223
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Comparing potential energy in non-relativistic classical physics and in special relativity
Preface
In classic physics the potential energy of a compressed (or stretched) spring is
$E_{\rm sp} = (\frac{1}{2})k_{\rm sp}(\Delta l)^2$
where $\Delta l$ is the length that the spring is compressed ...
- 87
1
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170
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Rindler Observers
In the process of transition from STR to GR, I'm trying to understand what Rindler observers actually are. Here is how one of the questions from our assignment defines them:
If the distance between B ...
- 67
1
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71
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Does electrical resistance increase with relative velocity due to relativity?
A spaceship is set up on earth with an RC oscillator driving a LED. It is set to flash once per second. The spaceship accelerates away to a velocity near C and the LED is now seen to be flashing once ...
- 129