I think this might be a very simple question, but I found no info on the net or in my chicken head... I've read M Kaku and Hawkings, and they write about a lot of paradoxes if time travel was possible (killing your parents, rewriting history, etc etc) I might be overlooking something, but if we travel thru time, there would be NO earth.. the earth has moved throughout space, AND throughout time... So if we travel back iin time, there won't be ANY Earth... My picture is this: If Mark and Lisa have a date at 12:00 at the park, but Marks gets stucked in traffic, and gets there 6 hours left, the very impatient Lisa would have already left.. She is ~somewhere~ else.. Likewise if we travel back in time, everything would be ~sometime~ else, even if we're in the same "place", the Earth is at a different "time"... Thanks for the help.