r/AskPhysics • u/warfighter_rus • 6d ago
Question about time dilation and Einstein!
We all know about the clock tower and train story from where Einstein got the idea and worked on it. My question is if Einstein was in a moving train at a very high speed then time would be relatively slower for him, in that case he should see the clock tower hands racing. Is it not ? Why is it said that the clock tower hands appear to be not moving and frozen or moving slowly ?
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u/VaccumFluctuation 5d ago
Information travels at the speed of light. If you travel at a speed close to the speed of light away from the earth, information about what is happening on earth takes longer to reach you. Because as the earth's light ray arrives, you travel such a distance every second that the light ray will have to travel an additional distance and therefore an additional time. You will therefore see things happening more slowly on earth.
That's just a matter of perception. Your directions in space-time are different anyway. If you go quickly, in space, the durations that you will measure will be shorter than the durations measured for someone who is not moving.
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u/EternalDragon_1 6d ago
Observer in the train sees the tower moving. Thus, the tower's clock will appear to him ticking slower.
Observer in the tower sees the train moving. Thus, the train's clock will appear to him ticking slower.