Sorry, this is ANOTHER time travel question...........

[Sonic]

I hope this isn't too much like all the other questions on here about time travel, but here goes-
Ok, I heard that if it was possible to travel back in time, you would go be in the 4th dimension (which, they say is time). Does that mean in that dimension every second in history, and in the future is acting itself out right now? How is this possible? Are the people there real? Do you exist there too? If you were to travel back in time and change a major thing, how would it effect now? Like, if you went back to the 18th century, and killed George Washington, would all of democracy just disappear that second? I know these are a lot of questions but I'm so confused!

------------------
Remember- If you're angry it takes 42 muscles to frown, and only a few muscles to smack the idiot that mad you angry in the first place.

[pluto]

My guess is that time travel is impossible because no one seems to be able to figure out what would really happen!

Some people think that it would be impossible to alter past history (what other kind of history is there?). What's past is past and it is immutable. Others, notably TV science fiction writers, think you could do whatever you want but of course there would be unexpected consequences when (if) you got back to your own time.

Just a clarification on this fourth dimension idea. Time is not considered the fourth dimension -- it just happens to be a very popular one. Using time as a fourth dimension is one of the bases for Einstein's theory of special relativity.

It is possible, and sometimes desirable, to talk about a fourth spatial dimension -- just like the three we are used to only at right angles to all three at once. In fact, there is no mathematical limit to the number of dimensions we can describe this way. Modern physical theories use ten- and twenty-six-dimensional spaces with a straight face. So describing time as the fourth dimension really doesn't add much to the discussion.


------------------
"non sunt multiplicanda entia praeter necessitatem"

[Lumpy]

If time itself were just another dimension, and you could somehow "see" time from the outside, then it would mean that both the past and the future would be fixed from some eternal standpoint. This contradicts human notions of free will, which is why many people feel it can't be that way.

According to one theory, what we experience as time is a progression (happening in a higher-order "metatime") of a boundary in fourth dimensional space-time. Think of dropping a single speck of ice into a mass of supercooled water: the water crystallizes into ice in an expanding front. In this analogy, the ice is the past, the boundary where the water is freezing is the present, and the mass of water an indefinite future.

If this theory is correct, then time travel would be impossible because the past would be "carved in stone", and the future wouldn't exist yet.

[ThufferinThuccotash]

We Tralfamadorians have laughed, are laughing and will always laugh at you naive humans who are hung up on linearity. You haven't seen, aren't seeing and will never see that all events are coincident. However, we have used, do use and will always use linearity as a silly premise in our sit-coms (ha-ha, Lucy never saw that coming!)

------------------
TT

"Believe those who seek the truth.
Doubt those who find it." --Andre Gide

[Czarcasm]

ANOTHER time travel question? Don't make me hop into the tardis and give your daddy a Trojan!

[AHunter3]

Time is a DIMENSION. There is indeed a "you" occupying 3-dimensional space at the temporal coordinate known as "8/21/99 at 1:45:17 PM EST". (Think about it: what were you doing then?).

If you imagine yourself sliding backwards along the time continuum to that temporal point...observe that the contents of your mind at that temporal coordinate would (or do), of course, have just as specific a definition as the contents of your pockets then and there, so if "you" could "go back" to 8/21/99 at 1:45:17 PM EST, you would be unaware of ever having experienced 8/23/99 at 2:44:41 PM, because that awareness does not exist in your mind at prior temporal locations.

In other words, the hole in the idea of time travel is the idea that you could "go back" rather than simply "be back" exactly as you were.



------------------
Designated Optional Signature at Bottom of Post