Stephen Hawking has gone to great lengths to promote science through books and videos, but he has been conspicuously absent in the software world — until now, that is. The astrophysicist has just teamed up with Random House on Snapshots of the Universe, his first official app. The $5 iPad title teaches the fundamentals of space through mini games: players learn about G-force with Einstein, put planets into orbit and come to grips with the theory of relativity.