Regarding “light clocks” and how moving clocks run slow: Does this mean that, if you were on the ISS or some other satellite, clocks on Earth run slow?

Question

I’m still very confused by how clocks could end up out of sync in this way. For example, if you were to send a clock into space, it “runs slow” for awhile, then bring it back to Earth, would it then be permanently “behind” unless it’s manually caught up?

In: Physics

Answer 1

I think perhaps you’re confusing yourself with talk of clocks running slow. Clocks always run at the same rate of one second per second whatever the circumstances. A person on Earth, a person on the ISS and a person on a half light speed galaxy hopper have exactly the same experience of time passing at a second per second. But their times differ. Here’s what that looks like at the relevant relative speeds (each s is a second passing).

Zero: ssssssssss

Fast: s s s s s s s

Faster: s s s s s s

Fastest: s s s s s