Time..

[Alex K]

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I think of time as a man-made parameter to try and make sense of what is happening. A label for snapshots of existence.

I'm not happy about calling it a dimension. To me, it bears no resemblance to the other dimensions of space that we know. Rather, the other dimensions are functions of this parameter.

I see absolutely no reason to think that the past or future "exist" in any shape or form, it's science fiction, along with the nonsense of time travel. Travelling at super-high speeds so you then arrive somewhere so that more "time has passed" there than you seem to have experienced is not travelling to the future. I've never even heard a sensible definition of what time travel is.

I know that relativity is concerned with time "slowing down" and such stuff. I don't disagree with all the theory, but I am very uncomfortable with some of the labels and assumptions.

The way I look at it, there is one global "time" that applies throughout the universe. It is the reference number for the snapshot of the whole universe at that point. Rather than say time is relative, I would say that the ways the laws of motion work change. Kind of like if someone is trying to walk through water, their speed is reduced, it doesn't mean that time has slowed down.

I think it's mathematically convenient to think of time as being relative, but it doesn't sit right with me. I think the laws of motion are the things that are altering, so a modifying factor is needed to account for this as "time slows down".

This may be semantics, it may be I just don't understand it well enough. But as I see it, as an external observer to the whole universe, you could advance things one "frame" at a time, and that would be what I would call time. You would be able to observe what was happening, and where "time has slowed down" you would instead just see things happening slower than you would expect as you move the frames along. (Obviously I mean as a continuum, not as discrete pockets!)

I have this problem with just throwing time in as another dimension and saying that it changes. To me, that violate the very definition of time, which is meant to be an external, independent parameter for keeping track of universal change.

I'm not claiming any of that is actually true or even makes sense, so I'm not going to try and defend it any further than stating it. It's just the only way I can make sense of the ideas at the moment. I need to learn more about relativity and stuff.

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Yes, you should learn more about special relativity, it provides an important different perspective on your question. What's so fascinating is not only that time gets stretched or compressed a bit at high speeds, but that the geometry of special relativity tells you that space and time mix when you change reference frames, i.e. when you move at different speeds. What is time for an observer moving relative to you, is, in special relativity, a combination of what's time for you and the spatial direction in which she's moving relative to you. This situation can be quantitatively illustrated using minkowski-diagrams:

http://en.wikipedia.org/wiki/Minkowski_diagram

This is quite the puzzle since in quantum mechanics, time plays such a special role compared to space: the space coordinates x,y,z are so-called operators acting on the states of the physical system in complicated ways, whereas time is an ordinary parameter. This is precisely why the synthesis of quantum mechanics and special relativity, called quantum field theory, demotes x,y,z to ordinary numerical parameters again, like time.