Awesome!
Where do I sign up?

Each of your sub-atomic molecules have to sign up separately.

Aww man!

Well thats the fine print for ya.

well i can say im an expert in physics (im far from it) but ive heard about what he is saying about the dimensions(the piece of paper/ paperclip) before so i dunno it sounds like hes got things figured out

Think about it this way. By what amount do you have to increase the mass contained in the universe to guarantee that it will end in a big crunch? How much mass do you have to add to make it happen immediately?

An easier way to imagine the implications:

Make a sphere with a radius that is 1 mile greater than the sun, positioned perfectly around the sun (a shell that is 1 mile away from the sun everywhere). That is the 'input' as it were, for your time machine. Every bit of matter and energy that crosses that line is sent, through compensation to the exact location of the sun 1 year in the past. The moment you switch the machine on, that moment to which all of the energy was sent, the sun's output would essentially double. How comfy do you think it would be on earth 8 minutes later?

Or start the same way, with the radius exactly the same as the sun, with a steadily decreasing radius. You would double the mass, and density of the sun... probably with quite a disastrous result.

That would be crazy we could figure out the entire history of the world. However what would happen if you change something would everyone forgot that it happened like would parts of books and information just disappear? Could you go back in time invent the computer before whoever invented it and now you are the one recognized as inventing it? If you save a person do you bring them back in the time with you or do they just appear back in the normal year. Would that mean that you are born again every single day and possibly reincarnated into yourself. Like you just keep recycling. Especially if you can not only go back into the past but you can visit the future. I think it would be cool but I'm still not convinced that it's possible.

I agree that it would definitely make things really confusing, but if it did happen I believe it would be restricted to a chosen few, or it would not be publicised at all.

If it ever happens in the future, why don't we know about it already?

Im already a time traveler....just really slow. 1 second per second......

That's exactly what I mean by confusing. :-P

When you go back and alter something you actually open up a seperate timeline in which your change has taken place. So no disappearing text books.

However, I still don't believe it is possible.

In the event that I am proven wrong, I will go back in time and change my answer. But that will never happen.

This discussion is moving a little too fast for me to go back and edit my posts... I changed both of them.

Did you go back in time to do that or did you just hit the edit button?

heh... edit button ;)

So, what does everyone think?

grandfather paradox:
you go back in time and kill your grandfather before your father was born.
how did you go back in time to kill him if your father was never born?

You would be going back in time to another time line, the paradox is non-existant in the theory of time travel. What you are looking at is the science fiction theory of time travel, in which you can go back in time and alter the course of your world. According the most accepted theories on this subject, you open up a new timeline in an alternate dimension when you go back in time. In other words, you go back in time and kill your grandpa, then you will never be born on that plain. BUT, in the timeline you came from, nothign has changed except that you disappeared.

You mean "sub-atomic particles".

If I could go back in time, I would attend all kinds of concerts.

Even if time travel is made possible, I don't think it should ever be used. Who can possibly tell of the effect it could have. No one person should have that kind of power.