Another thing (forgive my rambling), time travel will never be achieved for the simple fact that if you go back IN time to change something you will not have gotten into the time machine thus not going back in time to change the past.
And for anyone who doesn't know yet, here in about 5-20 years we will finally explore beyond our universe. In another 200-250 years we will achieve entering another galaxy (If we are not delayed by massive fallbacks ex. 9/11)
So for all you believers out there, keep believin'.