sam04u said:
Honestly... it's simply impossible to travel back of forward into time.
Uh, no. Time travel forwards is quite possible (even at variable speeds - such as faster or slower than the world around). Time travel backwards probably isn't.
Even if we looked at the universe through the string theory, multiple identical dimension, bullshit idea of the universe. For something to physically move from this universe to another point in time of the universe is impossible.
Maybe it seems impossible to you. Doesn't make it so. I agree
instantaneous time travel appears to be impossible as far as we know.
1) It would require the matter in the "past" to dissapear, and move to the "future". Matter can not dissapear.
Not a strong argument. You're basing it off the thermodynamic laws, which themselves are based of scientific observation. It's conceivable for a framework to exist which approximates our current understanding of physics in most cases. There could be extremities where things change significantly, though. This has happened before. C.f. classical mechanics and quantum mechanics.
String theory is the most likely candidate. I'm not sure humans will ever fully understand that, but I'm pretty convinced it's roughly the right direction, now (some of the mathematics of it describes our world quite nicely - as in it fits with our observations and predictions, while some other parts of it may or may not - but the thing to remember is that there are multiple running theories for it... and heck, they could all be wrong so far - once/if we're capable of testing them, we'll find out).
wikipedia said:
From a mathematical point of view, the energy conservation law is a consequence of the shift
symmetry of
time; energy conservation is implied by the empirical fact that the
laws of physics do not change with time itself
'empirical fact'. This is what science is, I know, but here is where the uncertainty comes in - science is the most accurate model of reality humans have ever built... but it's still a model. Biology and chemistry are fairly set in stone, but when you have the study of extremes (physics), it's a lot harder to be 100% confident.
So basically, conservation of energy only applies if the laws of physics do not change over time. You can probably see the dilemma; how do you know if the laws of physics are changing? Is it even detectable? What if it were happening over millions or billions of years? We don't even know how big the universe is - it could be infinite... what if the laws of physics are actually local? Certainly, our universe (the observable universe) is but a speck, assuming the universe continues on in the same density pattern as it does at the edges of detectable reality.
sam04u said:
The only rules we have in this universe is "matter/energy can neither be destroyed nor created", time travel breaks those rules.
That rule gets 'broken' a fair bit, actually. Look up virtual particles.
http://en.wikipedia.org/wiki/Virtual_particle#Pair_production
Certainly, matter can be spontaneously created from energy (including vacuum energy), at the very least (which actually isn't breaking the conservation laws, as long as corresponding anti-matter is created).
The question is, can information (not necessarily energy) be sent through a shortcut in time? I certainly don't know enough to give an answer, other than "it wouldn't surprise me". Why? Space is a dimension - and as such, the universe, and its other dimensions aren't distinct from each other, but linked together quite tightly in various ways... but that's getting into string theory.
On the topic of dimensions:
http://en.wikipedia.org/wiki/Virtual_particle#The_Loop_Interpretation_of_Virtual_Particle_Pairs