We leave so much unresolved in our past that we often wish we could just go back and fix things. Or, at least, change the way everything turned out.
We want to believe it's possible. We want to believe that science will make it possible. This is partly because we see far too many science fiction movies.
We also want to believe in an afterlife, just in case we need to atone for the things we've left in the past and couldn't get back while we were here.
However, in a BBC documentary that aired this week, astrophysicist Stephen Hawking offered nothing but bad news.
Hawking was speaking with Dara O'Briain, a comedian who also happens to have studied theoretical physics.
O'Briain was keen to know whether time travel was possible, especially the back-to-the-future kind. He mentioned that in 1992 Hawking had offered the "chronology protection conjecture," which insisted that if time travel were possible, it certainly could never be backwards time travel.
To read more, click here.