[reed13k]

Same thing that happens when that little rock flies up off the road and contacts your windshield... Or a bullet impacts something at speed ....Only more so.

Reminds me of a Scifi murder story where a prof crated a beam that eliminated all momentum within it. He demonstrated with a pool table. Lined up his enemy took the shot. Everyone was shocked to see the ball leave a perfect circle as it left earth instantaneously. No one but the prof considered the relative motion of the earth, solar system, etc... His enemy was left with a perfect hole through his chest.... I need to find that short story again... Good read.

[Steely Tom]

That short story is “Billiard Ball” and was written by Isaac Asimov.

[chrisser]

No one but the prof considered the relative motion of the earth, solar system, etc...

It is for this reason that I believe any practical attempt at time travel would also have to include instantaneous space travel.

Due to the rotation of the earth about it's axis and about the sun, and the expansion of the universe, it doesn't really matter if I can travel forward or backwards in time if I end up in the vacuum of space or somewhere inside the planet because the Earth moved between the two timepoints.

Even if you could somehow lock your frame of reference onto the planet, you still have the problem of changes in topography and structures. You could end up below ground, or significantly above ground, in the walls of a building or inside another person, animal, tree, etc.

Makes the actual travelling through time part seem relatively easy.