
Speaking of time travel, there have, of course, been many discussions of the problems with its portrayal in fiction, but one topic I've never seen mentioned is the whole "we can move you in time, but not in physical location" paradigm. Books or films sometimes use this to mandate that the time traveller who enters a machine in New York 2014 will come out in New York 1814, for example, and not Egypt, Peru, etc.
But surely, if one takes into account the rotation of the Earth, the revolution of the Earth around the sun, the motion of our solar system inside our galaxy, and the motion of our galaxy in the universe, the chances that any time traveller would end up even close to Earth are miniscule. Who knows, maybe the cold dead heart of space is littered with the frozen bodies of erstwhile time travellers...