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.

>>23
Dimensions?
Don't you think that after first 100 million years of evolution living organism would find way of moving in "other dimensions" if they existed to speed their chase after food or to run faster from predators? There is no more dimensions, and the three we know are not exactly distinct. There is one space but we think in terms of dimension because it helps us calculate vectors. Its only simple math. People who postulate "additional" dimensions need it to fit their inconsistent theories about subatomic particles to experimental data. BTW time is not a real dimension, it is just relation between causality and space.