h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

There are several possibilites I believe you may be interested in. If you want to know more about any of these just reply, I'll see it.

1) Quantum Universe Theories
According to quantum mechanics, any interaction has a finite number of possibilites, each of these then spawns a new universe in which one of these possibilites follows through. I suppose if you follow this theory through you could take the idea that, There is a universe for each opporotunity for something you could do in the past which would be different from your universe there by escaping the "infinite loop" clause so common in practical theory.

2) Frame of Reference Theories
As we have seen with everything else in physics, Everything is relative with everything else. Now, if we assume that were you to travel through time, you're frame of reference remains with you, effectively outting you from the time stream. Your past, the one that produced you is constant to your frame of reference, Therefore when you travel back in time any changes you make do not effect you because they occur after your frame of reference was reinserted into the time stream, or to you, in the present. This as well circumvents the paradoxes because were you to kill your mother, You would continue to exist beacuse you're frame of reference existed with it's complete past attached, prior to that event.

3) Free Will vs. Determinism
Whoever said we had free will? It is possible that no free will ever existed, we just assume it does because we arrive at our choices after specific thoughts and feelings lead to that decision. But it is possible that time is a trick of the mind, and is simply the interrelationship between matter and energy. The influences of one on the other causes us to see time as moving forward and maleable, but in fact we have no more ability to change it than we have of altering the courses of the stars. Meaning all things in the future and past exist as constant unchangeable events. Any time travel that has occured always will occur. Therefore you would not exist to kill your mother because the death of your mother would cause you to never exist.

Anyway, there are a couple of things that can be said about wormholes, You mentioned that the existence of anti-gravity would be required. Though no one is sure even if the particle exists in the first place, or what it does, the existence of an anti-graviton would possibly create negative gravity, though unlikely.
Also, I suppose the existence of wormholes would seem weird to us because it involves twisting things in ways we can't perceive. But to go back to the two dimensional ant. The ant, because it is two dimensional can't perceive of any such thing as a third dimension, there is no way to, You see 4 cardinal directions and that is it. No up or down. But you being in the third dimension can and therefore you know those two dimensions can be altered. You relize it is possible in the fourth dimension. Applying this analogy to us and wormholes, we see that it may just be possible that even though we can't perceive it, it may actually work.

Well these thoughts are just some ideas I've collected, hope they're helpful. Have fun with them.

About your theories:

1. I really don't understand your quantum mechanics theory. Did you leave out some punctuation marks, or is this just my imagination? Since I don't understand this, I can't support of refute it.

2. Yes, everything is relitive. However, there is a problem with this theory. What would outside observers looking at my history see? Would they see me kill my mam, then pop into existance right when I would have born? Would they see me miriculously appear at the time that I reture from killing my mother, thereby making them never see my birth? I have some serious resignations against this theory.

3. This theory, in my opinion, could work. It could be that, if I went back in time planning to kill myself, some unforseen event would provent me from doing so, so that no mater what I did, I could not kill my mom. Sadly, there is no way that I know of to prove this theory. Oh well.

4. Yes, it is true, just because we, as humans, can't comprehend a concept doesn't mean it doesn't exist. It is possible there is a forth dimention of space (I really don't think time should count as a dimention). If there is, then, at least in theory, we could create a wormhole. Whether we could actually make one is another matter. Could the ant have drilled the holes, bent the paper, attached the straw? It may be that only four-dimentional beings could create a wormhole.

You have some very interesting theories. Keep thinking!

To put 1 and 2 into better terms

1) Actually this was an early quantum theory and is much simpler than I originally explained it. Whenever some event occurs, there are a set of possible outcomes. For every outcome there is a new universe "spawned" to follow that path, so for every choice there is a universe. It's possible that these could be at parallel stages so that if you were to go back in time, you would actually be shunted to another universe in which you're event occurs and the original universe is left intact.

2) Actually this is the I put the most stock into. Since your frame of reference is moving you're existence resides at whatever your current frame of reference would. But no one elses frame of reference would. Lets say you go back in time and kill your mother. You exist because your frame of reference was pushed back. Now because your frame of refernce keeps you intact and keeps your past constant and free from disruptions you continue to exist. Now we view time linearly so let us take it at that. We will look at two things frame of reference and "reality" where t=0 is the time you kill your mother

First the unaltered view
at t=-1 you do not exist but your ancestors (mother) do
t=0 nothing happens your mother continues to live
t=1 you are born frame of reference begins
lets say t=40 you travel through time to at=-1 ((at) is altered time)

at=-1 your ancestors exist and your frame of refrence exists containing the points t=1 through 1=40.

at=0 you kill your mother. Your frame of refrence continues to exist but now contains the points t=1 through t=40 and at=-1 to at=0

at=1 nothing happens no mother no child, but your frame of refrence still exists because in it's history you were born at t=1 even if you weren't born at at=1 because that occurs after you begin to exist linearly.

at=40 no one travles back in time but your frame of refernce is still there still flowing linearly. (the interesting thing is this principle explains why you've now existed for a total of 82 units of time even though you would have only existed for 40 units)

as for 3 and 4, my sentiments exactly. I hope this cleared somethings up, Looking at it now it seems kinda confusing but I'll post it anyway on the long shot you can pick out my logic

Sorry about my spelling.

Some more ideas about theory no.1...

One of the more amazing ideas of quantum theory is the Feynman sum over histories. The technical version is that a particle can travel from point A to point B along many paths, with a different probability for every path. Many of the probabilities cancel each other out along the way, though.
The generalised version of this idea is that there are many possible histories for any fool who decides to go back in time to kill his mother, which means that there is actually a history in which you didn't kill your mother...leaving her still alive and you still in existence.

Of course, the upshot is that you might see a guy on the street with a sign saying, "Lost in time. Wrong Universe. Can't get back. Heeeelp!"