Time Travel

I spend a lot of time thinking about time travel, and how to go about doing it - and I've come to an interesting realization.

It seems to me that our conceptualization of time travel is this: Someone is at point A originally in time, and they end up at point B at some later point in time - perhaps the point in time when you finally discover the secret of time travel and make your time machine. You take said time machine and reverse time and wow! You look around and the aforementioned person is back at point A. (You're off building your time machine still, hopefully - if you haven't altered events with your presence.)

However, if we go by special relativity (which we should, at least until Einstein is proven wrong), then time is all relative. That is to say, if you travel at the speed of light, you and your reference frame will theoretically experience no passage of time. If you travel faster than another person, your watch will run slower relative to theirs. So then, if you take your time machine and put yourself in it and *travel through time*, it seems to me that what will actually happen is you will go back in time - you'll make yourself younger. You're within a reference frame that has been moving continuously slower in relation to outside reference frames until time reverses. Inside your reference frame.

This might suggest that the way to get the time reversal outside of your reference frame is to move slower than everything else - so slow that you hit absolute zero. And then take away heat. (This is Greg's idea, I want you all to know.)

But here's the thing - according to the conceptualization of time that I noted above, we haven't just reversed time, we've reversed movement through space. So, spacetime. Does movement through time include movement through space? Should time travel really be called spacetime travel? And how do you account for the travel through space? How do you get that person from point B back to point A, instead of just making them younger?

Man. Every time I think I've come up with an interesting note about time travel, I realize that I haven't really. Greg and I had this really awesome discussion about it, and at the end he went "So, there can only be two conclusions [of our theoretical time travel test]. Either we can or we can't."

Anyway, this'll be interesting to come back to next time I think I've come up with something.

Added 1/23: interesting point brought up by Dan/his physics teacher: if you travel faster than the speed of light, you're just traveling faster than light. So you could potentially view events that happened in the past, but you couldn't interact with them, or change them in any way. Hmmm.