Gaze out into the night sky and wonder: Are we alone? Are there stars like our Sun, with planets like Earth, with life—with complex, and even intelligent, life? We've known for many decades now that there are stars like our Sun. Indeed, we orbit an unremarkable star. But now we have begun to push the question one step further; we know now that there are planets around other stars. Within the past decade, astronomers have discovered large planets orbiting close to Sun-like stars. This is arguably the most exciting result in astronomy for the past twenty years and could herald the beginning of an age of planetary discovery leading to the ultimate prize: the detection of Earth-size planets orbiting in the habitable zone of Sun-like stars.