[Rincewind (OP)]

This is a question about general relativity for something I'm writing.  I think I get it but relativity's a bit of a brain bender.

The situation is this.  If one craft leaves the Earth and approaches light speed, then another craft leaves in the same manner, approaching the same speed and then they arrive one after the other at their destination, would they have experienced the same amount of time ie would any age gap between the two pilots remin the same?  I think they would have but confirmation would be nice.

I also need to know, but I think it's simply the twins paradox, if the first pilot turned around and came back (if the second couldn't foolow for whatever reason) would the age gap between them be significantly different (ie the one who never left would be much older or even dead) than when the first pilot left, given he reached near light speeed before turning around?  I think it would but again, best to make sure.

Cheers guys

[DoctorBeaver]

If their rates of acceleration/deceleration were the same they would experience the same amount of time dilation.

I also need to know, but I think it's simply the twins paradox, if the first pilot turned around and came back (if the second couldn't foolow for whatever reason) would the age gap between them be significantly different (ie the one who never left would be much older or even dead) than when the first pilot left, given he reached near light speeed before turning around?  I think it would but again, best to make sure.

The 1 who stayed behind would be older. How much older would depend on the length of the journey and acceleration rate.

[Rincewind (OP)]

That's exactly what I thought.  Cheers Doc!

[DoctorBeaver]

My pleasure. I'll help anyone whose staff has a knob on the end - even if they can't spell WIZARD  []

[lyner]

The fact is that there is no paradox in what you said.
The 'paradox' refers to a situation where each twin (or clock)  would, see the other as aging less than himself as they flew past each other. It's a Special Relativity experiment in which they are both moving at constant speed.
The process of the twins getting back together again - and one of them having accelerated so that he could return to the other - resolves the paradox. The one who 'made the trip' would be the one who had done all the work and he would be the one who aged slower. (Both twins would agree about this). If they both left and returned, they could both turn up on their 50th birthday.