Thought experiment about special relativity

Question

Hypothetical scenario:

Observers A and B exist
The way A experiences time is the baseline
B is moving at a speed such that for it, time passes 2x as slow as the baseline(i.e. 2 year for A is 1 year for B)

If they observed eachother, would A see B as moving in slow motion and B see A as moving in fast motion?

However B can claim to be at rest while A is moving in the opposite direction, relative to B. — Triatticus, Aug 28 '23 at 16:01
I mean if one was able to look at the other and see what it was doing while passing. — NE0bject _, Aug 28 '23 at 17:45
Does this answer your question? How can time dilation be symmetric? — John Rennie, Aug 28 '23 at 17:52

score 1 · Answer 1 · answered Aug 28 '23 at 16:32

If they are two observers totally independent of each other, A wouldn’t be a baseline (motion is relative). Each sees the other as moving at 0.86c.

Now, if B was originally at rest relative to A and then accelerated to 0.86c, then we have a situation not unlike the Twin Paradox. Now A is the “baseline,” since B is in an accelerated frame.

The latter is the only situation we would run into with spacecraft leaving and returning to Earth. I’d look up the Twin Paradox and it’s accepted resolution for further details.

Thought experiment about special relativity

1 Answers1