- #1
DiracPool
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Thought experiment: Alice, Bob, and the planet Zolan.
Alice is floating in space 10 light seconds from the planet Zolan (Z) with a radio emitter and detector. She and planet Z are in the same rest frame. Bob has the same devices as Alice but is on planet Z. Bob then accelerates from planet Z toward Alice and then stops accelerating once he reaches a velocity of 0.5c relative to planet Z (and Alice, of course).
At the instant Bob reaches Alice's position, they both simultaneously shine their radio emitters at a reflector on planet Z and leave the emitters running. Say the frequency of the radiation is 1000 kiloHertz.
Here are my assumptions. 1) At the end of 20 seconds, Alice's detector will detect both her's and Bob's emitted signal, and read that the signal reflected by her emitter is still 1000 kH, but Bob's is less than 1000 kH.
2) Bob, on the other hand, from within his reference frame, will detect both his and Alice's signal at the same time, but the time elapsed will be well after 20 seconds according to his clock. Furthermore, both his and Alice's signal will read less than 1000 kH on his detector, although his emitted signal's frequency will read even less than Alice's, the reason being that Bob's reading of his own signal has a doppler shift going in both directions, while Bob's reading of Alice's signal only has a doppler shift after being reflected from planet Z.
Are these assumptions correct?
Alice is floating in space 10 light seconds from the planet Zolan (Z) with a radio emitter and detector. She and planet Z are in the same rest frame. Bob has the same devices as Alice but is on planet Z. Bob then accelerates from planet Z toward Alice and then stops accelerating once he reaches a velocity of 0.5c relative to planet Z (and Alice, of course).
At the instant Bob reaches Alice's position, they both simultaneously shine their radio emitters at a reflector on planet Z and leave the emitters running. Say the frequency of the radiation is 1000 kiloHertz.
Here are my assumptions. 1) At the end of 20 seconds, Alice's detector will detect both her's and Bob's emitted signal, and read that the signal reflected by her emitter is still 1000 kH, but Bob's is less than 1000 kH.
2) Bob, on the other hand, from within his reference frame, will detect both his and Alice's signal at the same time, but the time elapsed will be well after 20 seconds according to his clock. Furthermore, both his and Alice's signal will read less than 1000 kH on his detector, although his emitted signal's frequency will read even less than Alice's, the reason being that Bob's reading of his own signal has a doppler shift going in both directions, while Bob's reading of Alice's signal only has a doppler shift after being reflected from planet Z.
Are these assumptions correct?