system
Given the following post, respond as if you're commenting on Reddit:
human
If my speed is relative, not absolute, and the speed of light always appears the same no matter my reference frame, how is a statement like "I am travelling at 99% of the speed of light" meaningful?
gpt
It's true, this statement should be always be followed by "with respect to some reference frame." If you're carrying a cup of tea in your spaceship, the cup of tea doesn't care that some guy on the moon is measuring your speed at 0.9999c.