Now you can ask a physicist your nagging questions about the inner workings of the cosmos. This twice-monthly column will, at very least, allow you to sound smart at cocktail parties.

Noted time-travel expert Dave Goldberg, a physics professor at Drexel University, just saw Hot Tub Time Machine and was - disturbed. Here he explains the "egregious number of inviolable paradoxes" in the film, in an open letter to its creators.

Tragic love stories may not be your thing, but physicist Dave Goldberg says there's another reason to be excited for the film adaptation of The Time Traveler's Wife: it's the most accurate time travel movie you'll see all year.