@north,
This topic and similar topics such as time and space interest me. I think I have a unique way of looking at and examining the subject. I want to just mention a little bit, hopefully to continue the discussion without derailing off the main topic because I think they are related.
Let's start with relativity. Einstein essentially suggests that the greater the velocity the slower time moves for that object. So the closer you get to the speed of light, the slower time moves. Many people have a hard time grasping this concept. But don't worry about trying to understand it, let's look at the implications of it.
Now the Earth is moving through space constantly. We are captured by our star and our star is moving in the galaxy but ALSO the galaxy is moving, not just rotating but moving on a tangent. The estimated velocity of the earth through space is roughly four hundred thousand kilometers per second. That is fast.
So let's say we select a static point in space and compare the time of that static point with the time on Earth moving at 400k/s. This means that time on the Earth is actually moving slower than that of static space!
Who cares? What does it mean? Well if you could create a space ship that could nullify ALL velocity, meaning you become completely static, not moving with the galaxy. Not moving at all peroid. Time would speed up for you. You would see the galaxy SPEEDING up as it moved away from you. Sound familiar?
It is not easy to imagine and it would be difficult to have a zero velocity relative to everything because gravity is not easy to escape. But if you could time would speed up a lot. If I am right it means that there are two relative time frames. It means that static time has LONG since passed us and continues to. So fixed space is actually FAR into the future than we are.
This becomes interesting if space is a substance or if space wells up virtual particles. It means that what ever static space does, it has been doing it far longer than we have because of the rate of time passing. This creates a sort of paradox if you go far enough into the future. This could actually be the cause of the expansion of the universe. When you have static space moving through time faster than matter. It creates a sort of ripple effect.