Bartosz Milewski on Nostr: When you're learning special relativity, things like relativistic contraction are ...

When you're learning special relativity, things like relativistic contraction are explained by switching between inertial frames. The stationary observer watches the moving observer bouncing rays of light back and forth to measure distances. In the stationary frame, the moving train car is shorter. This is how you measure things. It's not the same as how you _see_ things, which is what I was talking about before.