LogFAQs > #963153302

adjl posted...

Yep. The earth orbits the sun at ~30 km/s, which is in turn is flying through space at ~370 km/s (it orbits the centre of the Milky Way, but its orbital period is ~226 million years, so we can simplify it as linear motion on the time scale of humanity's brief blip of existence), so depending on where the earth is in its orbit, it's going to move somewhere between 340 and 400 km for every second you travel through time, without you. Most fictional time travel either ignores this or comes up with some vaguely plausible explanation for why it's not an issue, but if you're attempting to travel only through time and not space, there's virtually zero chance of you ever ending up on the surface of the earth again, let alone in the spot you want.

As much as absolute coordinate systems are common in sci-fi, they really do not respect how dynamic celestial bodies really are. Even space itself is not static; there's really no absolute frame of reference from which to measure anything.

What if you stay within earth's gravity as you travel back? You'd pretty much get dragged with the earth back into time