About This Video

Physicist Stephen Hawking once postulated that time travel must be impossible. If that were not the case, we would be inundated with tourists from the future. Here, the author of The Physics of Star Trek, Lawrence Krauss, points out another hitch, while perhaps exposing the kinds of things that theoretical physicists really sit around and talk about. In doing so, he teases apart the most baffling paradox related to the possibility of time travel: the so-called “grandmother paradox.”

Image courtesy of Tamás Mészáros; Recorded June 2010; Posted September 2010