2 ms·

> your clock moving faster doesn't mean you get your buddy's light signals "in advance" Thanks, this helps a lot! I think I have just one more question :D I c

> your clock moving faster doesn't mean you get your buddy's light signals "in advance" Thanks, this helps a lot! I think I have just one more question :D I can send him a signal too, right?: I can stop accelerating, or beam him back at the speed of light. When I receive the signal at 12:50:01.250058 I stop accelerating. 1.25 seconds later at 12:50:02.500000 (his clock) my buddy sees that I sent him a response by stopping my acceleration. Or does he see me stopping when his clock is at 12:50:02.500058? If he sees it at 12:50:02.500000, no one gets information in advance, but I gained 58 microseconds that I could use to run a computer program for a little longer, as an example, and make a better statistical prediction than he could do on the ground. Or do I lose the ability to use those 58 microseconds in some way?

pdonis 2y ago
> I can send him a signal too, right? Yes. Rather than stop accelerating (you weren't in the first place, you were in a free fall orbit in my scenario), you can just send a light signal back, which is a lot simpler--and uses a lot less rocket fuel. :-) Suppose you receive your buddy's signal at 12:50:01.250058 and immediately send one back. Your buddy will receive that signal at 12:50:02.5000000 by his clock. No 58 microsecond gain, since his clock didn't gain that time, only yours did. > gained 58 microseconds that I could use to run a computer program for a little longer, as an example Yes. The Interstellar scenario discussed upthread gives a much more extreme example (and in my response I gave a similar scenario but involving speed instead of using the gravity of a supermassive rotating black hole to get the time dilation effect).
- alganet 2y ago
  Cool, thanks! That was exactly what I was trying to wrap my head around.

2 ms·

> your clock moving faster doesn't mean you get your buddy's light signals "in advance" Thanks, this helps a lot! I think I have just one more question :D I c

by alganet 2y ago

pdonis 2y ago
> I can send him a signal too, right? Yes. Rather than stop accelerating (you weren't in the first place, you were in a free fall orbit in my scenario), you can just send a light signal back, which is a lot simpler--and uses a lot less rocket fuel. :-) Suppose you receive your buddy's signal at 12:50:01.250058 and immediately send one back. Your buddy will receive that signal at 12:50:02.5000000 by his clock. No 58 microsecond gain, since his clock didn't gain that time, only yours did. > gained 58 microseconds that I could use to run a computer program for a little longer, as an example Yes. The Interstellar scenario discussed upthread gives a much more extreme example (and in my response I gave a similar scenario but involving speed instead of using the gravity of a supermassive rotating black hole to get the time dilation effect).
- alganet 2y ago
  Cool, thanks! That was exactly what I was trying to wrap my head around.