Assuming we are going into the past, not into the future, have we stopped to think of just how many changes we will make in what is current history? The utilization of lectricity - and threfore, the recording industry - will be invented x centuries before it did happen. Interstate highways will have run across the continent for however long.

Oh, dear, I just had an an awful thought- do you suppose someone came back to our current day and is rapidly changing it into what they are experiencing eons from now? If you follow that...