Nattekat

Nattekat t1_j2afp4g wrote

Doesn't there have to be some reference frame whereby a body is not moving through space at all? Not under influence of any force, just the expansion of the universe all around it making it seem as if it's accelerating from any observer.

Under the laws of special relativity an observer in a space ship travelling at 0.1c will see Earth speed up, while an observer on Earth will see the ship slow down. But if all speed is relative, both should see the other speed up, which feels paradoxical.

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