Major problem with time travel

Movies that feature time travel or even the general conception of the idea is like this: You retain your position in space and travel through time to appear at the same place in future or past. Here is my problem, did nobody else foresee this? If you go back in time and conserve your momentum( seems like a must) to appear at the same place, you will most likely end up in empty space or in a star because the earth, solar system, milky way galaxy fucking moves in space. With our current momentum we can't match Earth's motion through space and all travelers will die in vain.
Jumping in your DeLorean and appearing at the same place in future huh? No, you will drift in space with 85 miles per hour to eternity.

ITT: kids who know nothing about science pretending they do. See, I'm at least a kid who'll say what he doesn't know.  I don't know if time travel is possible, I don't know if wormholes exist (but I do know that they have been hypothesized by more than television), and I don't know how 3-d relativity necessarily behaves while traveling backwards through time.  Just....everyone attempt to use a bit of logic and refrain from using personal insults to prove your point.

>>21
This guy nor anyone else has said that they believe wormholes exist.  We have all just said that they have been hypothesized by actual scientists.