If I Could Put Time in a Bottle... (I'd Probably Spill It)

Physicist Sean Carroll, blogging at Discover Magazine online, offers up these rules for time travel.

Rule No. 10 is bound to be a major disappointment for those of us who wish we could re-write our past decisions. Of course, if we actually could go back and do that, the movie The Butterfly Effect shows us the horrifying consequences: We would become Ashton Kutcher.

(H/T Opuszine)