Everyone assumes that time travel is already a possibility--a time machine already exists. Well, since travelling really really fast is what enables time travel, all you need is a light-speed ship, right? The thing is, the faster you go, the more mass you have, thus requiring a larger enginge. With present energy 'makers,' (power plants, hehe) if you will, this would not work, because for a 10 tonne ship to travel the speed of light or faster you would need I think it was 5.1*10^26 which would be 510,000,000,000,000,000,000,000,000 (I think
) jules of energy, which obviously requires a huge engine.
A huge engine requires a huge energy source. Right now the largest energy producing method is nuclear energy. Soon, we hope to obtain fusion energy, which puts out proportionally more energy than nuclear fission. The thing scientists are looking for is something that if you put in a certain amount of energy, it will put out more energy than it took in. There is another source of power no one has been able to harness. Now, in theory, if we were to combine matter with antimatter, there would be 1 of 2 things:
1. A huge explosion=no controlled energy
2. Controlling this energy, we would gain an infinite source of power.
Ok. Now we've found a power source for our time travel machine. (If any of you've seen Star Trek: Enterprise, they talk about antimatter engines in one of their episodes) Anyway, after billions of dollars on research and thousands of failed experiments, we have harnessed antimatter and created an engine to convert the energy into propelling the ship into light-speed.
Then there's the question about physics. Einstein proved in his theories and studies that
nothing can ever go faster than the speed of light. You might get .0000000000000000000000000000000000001 (obviously it goes on forever)away, just never exceed it. Thus, you can't go faster than light=no real time travel...
So, is time travel really possible? Yes, because we know that if you go really really fast time bends with you, slowing it down. Is it possible to go back or forward significantly in time to change the present/past/future? I leave that up to you.
Say time travel is truly a reality. Then we go on to the question about paradoxes and such. Personally, I
hate to think about those things, it just hurts my little head. you know, granpas dead, you're dead, but you were born, so you get different parents, etc, etc.