Point A in spacetime to Point B in space time is calculated by the distance in time (hours, days, etc,...) plus the distance moved during that time within the 3 dimensions of space.
So the spacetime distance from A to B is calculated by t + l + w + h (time plus length plus width plus height). Let's call A to B....A/B
A/B = t + l + w +h
If l and t and h are large, t is less.
So if you move around a lot, but arrive at Point B in space-time, then you had to have had spent less time doing it. Keep in mind we are not talking about Point B in space, but Point B in space-time.
If you don't move at all, then you only spent time getting there, and so had to have spent more time getting there. The longest way to get there as far as time is sitting still.
At least that's my idea of a simple explanation......hmmmm...maybe not right though.
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