"Time" not a dimension.

[lilphil1989]

And that was the fact with the omnipresence that mattered: if two observers see two event A, and B, differently (e.g. one sees it B before A, the other sees A and B in the same time), then an omnipresent being 'notices' the 'correct' order of the events, because he doesn't 'look' from a distance to the event, and is not moving at all. And if we have a 'correct' order of events - from 'someone' who doesn't 'look' from a distance and is not moving at all - then that is a global time. If the logic is correct so far, then it means that even if the omnipresent being does not exist, this 'global time' should exist.

As soon as you say that the observer is not moving, you have implicitly chosen a specific inertial frame which is at rest with respect to some object, or set of objects. This choice defines your definition of simultaneity, which is in no way global, since it holds only in your chosen frame.

The thing you have explained with the observers sounds something like a "subjective view". And the reason I inserted that omnipresent being was in an attempt to explain an "objective view". I hope you understand what I'm talking about.

I do understand. But the existence of such an objective view is entirely uncompatible with relativity. And since relativity correctly predicts the outcome of experiments, it seems to be a good description of the way the universe works, and the lack of an objective definition of time seems to be the way it really is.

As about two events happening simultaneously: imagine the universe scaled so that you would see it all, in front of you (now you see the things objectively), and you see two specific stars at the same time, and one star dies, and after that the other one dies. How do you imagine those two stars in two different local times, dying in the same time, yet one after another?

Now imagine I ran away from the scaled universe rather quickly. In my rest frame, the events would no longer be simultaneous. That's the key point, your definition of simultaneity depends entirely on your state of motion.



Here's the Wikipedia article on the relativistic corrections for GPS.