Totally mechanized infantry

[giblets]

Doesn't time travel contradict conservation of mass and energy?

[The Mad Monk]

How the hell should I know?

Here's a video on the higher dimensions:



Here's a really cool AMV:

[N35t0r]

I've seen a 1 minute video that explains why time travel will never be possible. IIRC there was am armed guy and he went through a portal than transported him 30 seconds back in time.

He exits the portal and can see the older himself going through the portal.

If he shoots him, then this creates a paradox that is unsolvable because who then would go through the portal to shoot himself later/earlier? , so time travel can't exist :/

That's only a hazard if there is free will.

If free will is only an illusion, and we're only 'seeing the landscape as it rolls by' from a time point of view, then the fact that we are here means that there isn't any 'temporal paradox' to **** the universe up.

[Bereta_Eder]

So in order for time travel to exist, free will must not. Ok.

[loinburger]

Another option is that the future and the past exist in different "universes." You are in Universe A in the year X, you travel back in time to the year X-1 and kill yourself, but in doing so you've caused the universe to diverge off into Universe B - you still exist because you came from Universe A in the year X, whereas you've killed yourself in Universe B in the year X.

[Bereta_Eder]

So the way to fill all the difference universes with myriads of your progeny is ironically to keep killing yourself.
Amazing.

[giblets]

Well no, anything you do that changes the past will put you in a different universe. It doesn't have to be something bad like killing yourself.

[Bereta_Eder]

So it can be something less bloody like farting in an elevator?

[N35t0r]

Another option is that the future and the past exist in different "universes." You are in Universe A in the year X, you travel back in time to the year X-1 and kill yourself, but in doing so you've caused the universe to diverge off into Universe B - you still exist because you came from Universe A in the year X, whereas you've killed yourself in Universe B in the year X.

That's not technically time travel, that's just travelling to a universe that's the same as ours but x time in the past. If those exist, then there must be countless other universes with more marked differences (or just other differences, for instance one in which I am left handed), and finding the 'correct' ones for 'time travel' becomes increasingly complicated...

[loinburger]

In Ray Bradbury's "Sound of Thunder" a guy screws up the future by stepping on a prehistoric butterfly

[N35t0r]

Yeah

[Bereta_Eder]

I'll check it out

[loinburger]

http://www.scaryforkids.com/a-sound-of-thunder/

[Elok]

In Ray Bradbury's "Sound of Thunder" a guy screws up the future by stepping on a prehistoric butterfly

Something that I always wondered about the whole question of time travel: wouldn't the mere act of traveling back alter the past, whether you did anything or not? You're breathing the air, shedding skin, introducing different germs, your particles are interacting with everything around--the world is going to be subtly different. That in turn means that the you who traveled back in time will be subtly different, since the change is bound to affect at least one molecule that winds up in your body somehow (unless you traveled to a distant galaxy, or a very faraway place a very short time ago). That in turn modifies the body which goes back in time, which modifies its previous modification, and so on a potentially infinite number of times. So it doesn't matter how little difference you make by presence; the recursiveness of time travel will magnify all distinctions.

[loinburger]

Yeah, even if you send back a completely sterile robot or something that floats in the air (so no crushed grass etc) then it's still going to be displacing air and effecting minute changes in gravity etc - over the course of a few thousand years those changes are going to add up (e.g. the displaced air in 2000BC might cause a tornado in 500AD or something). The only semi-plausible science fiction time travel stories I've read either rely on infinite universes or else reduce time travel to mere scrying (so nobody actually time travels, they just look into the past and hence don't affect it).