First of all, these are great responses, so thanks all.
What I meant by here:
Is how are the people actually aging differently due to time dilation. I mean, I know depending on from where you are observing, γ can be different, but surely you don't age differently depending on where the...
This is something that interested me after reading about time dilation. For the point of making it simpler, ignore relativity relating to gravitational fields
Lets say for example, that the Earth does not orbit the sun, and the solar system doesn't orbit within the galaxy etc (makes it easier...