Wormholes. I think they're way cool and speak to time travel as being possible. But that's fitted in to string theory, isn't it?

i listened to a guy on NPR talk about building a time machine and wanting to go back to see his dad who died.

There's a thing called a paradox, time travel creates that implicitly--see the Harry Potter you can't be in two places at one time and don't let yourself see yourself thing. So if you did create a time machine, you couldn't create a paradox.

But he said he couldn't go back to see his dad. My question is why? Why couldn't you go back?

I mean seriously, if time travel is not just a theory and is a product of natural law, it IS possible and we just don't know how to do it yet, then the idea that if you went past the time/date you created the time machine would mean that it wouldn't cease to exist at the very moment you crossed that creation time/date. You'd be able to go past.

So what that means is that if I invented the machine today, I could still go back to 3 tuesdays ago if I wanted. I wouldn't have to wait for 3 tuesdays from now and go back to the day the machine was invented.

Then again, if time travel's possible, couldn't you, in theory, cease to exist if you go past the time of your birth? Or would that create a paradox of incredible proportions if you actually went back prior to your birth.

Anti-matter's way cool stuff. I think, just like nano-technology, it has interesting applications if we learn to use it.

Nano-technology's always intrigued me.

Also I love how you slow down time the further away from Earth's gravity you get. It would be fun to measure if that holds true and how FAST you slow it down if you go to a planet with a stronger gravitational pull. Does the amount of gravity make a difference on how fast time slows down or no?