Time Travel Question (from A Briefer History of Time )

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Time Travel Question (from "A Briefer History of Time")

I read the original "A Brief History of Time" and is now reading "A Briefer History of Time". :P

There is a part about time travel that confuses me. Does anyone want to enlighten me using layman terms? (i am a mathematics major, not a physics major >_<) It is on page 108-109 of the book "A Briefer History of Time" in the chapter "Wormholes and Time Travel" if anyone wants to refer to it.

The scenario described is this:

1) An event A happens on Earth. 1 hour Earth time after event A, event B happens on another planet (Proxima Centauri, PC) which is 4 light years away.

2) Someone on Earth during event A can only get to event B if he is capable of faster than light (FTL) travel since B is 4 light years away.

3) To an observer on PC moving away from Earth at nearly the speed of light, it would appear the order of the events is reversed: event B appears to occur before event A. This observer would say its possible, if you could travel FTL, to get from B to A.
 
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Yes, this is the kind of thing that occurs if you posit FTL. Cause and effect can get reversed, which is one of the reasons it is believed that FTL is not and never will be possible.

FTL will make your head hurt. :smile:
 
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