Thought experiment for general rel., I can't remember how it goes

In summary, the equivalence principle states that a rocket sitting vertically in a gravity field will also detect blueshift for light emitted at the front and detected at the back.
  • #1
ericqb
4
0
There is a thought experiment pertaining to general relativity that involves a signal traveling from the front to the back of an accelerating space ship, if I remember correctly. I'm sorry for being so vague, but this is something I saw browsing in a library years ago, and I really wanted to think about it, but it slipped out of my mind and now I'm not sure how it goes. I believe that astronaut 1 in the front of the ship sends a pulse of light towards astronaut 2 in the back of the ship. The question is, I believe, how does the transit of this pulse compare to the same pulse in a ship that is moving at a constant velocity instead of accelerating. I'm not sure how much of this I have right but there is a thought experiment with a signal involving two astronauts in the front and back of a spaceship that is accelerating. Can someone lead me to this thought experiment and a discussion? Thank you so much. Sorry for the vagueness. ericqb
 
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  • #2
I think you are interested in the proof of gravitational time dilation using the equivalence principle. If a light of a certain frequency is emitted at the front of an accelerating rocket then by the time the light reaches a detector at the back of the rocket the detector will be going a different velocity and by the Doppler effect will detect a higher frequency. Therefore, by the equivalence principle a rocket sitting vertically in a gravity field will also detect blueshift for light emitted at the front and detected at the back.
 
  • #4
Dear DaleSpam,

Thank you for your help. Sorry it took me so long to reply.

ericqb
 

What is a thought experiment in general relativity?

A thought experiment in general relativity is a mental exercise that helps us understand complex concepts in physics, specifically related to Einstein's theory of general relativity. It involves imagining a hypothetical scenario and using logical reasoning to predict the outcome.

How does a thought experiment help us understand general relativity?

Thought experiments allow us to explore the consequences of Einstein's theory of general relativity without conducting actual experiments. They help us visualize and conceptualize complex ideas, leading to a deeper understanding of the principles of general relativity.

What are some famous thought experiments related to general relativity?

Some famous thought experiments related to general relativity include Einstein's elevator experiment, the twin paradox, and the black hole information paradox. These scenarios help us understand the effects of gravity, time dilation, and the behavior of matter in extreme conditions.

Can thought experiments in general relativity be proven or disproven?

No, thought experiments cannot be proven or disproven as they are hypothetical scenarios. However, they can be used to make predictions that can be tested through actual experiments or observations.

Are thought experiments only used in general relativity?

No, thought experiments are used in various fields of science, including physics, biology, and psychology. They are a valuable tool for exploring complex concepts and theories that cannot be easily tested through traditional experiments.

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