Cosmic Matters

Exploring New Worlds

On a clear, crisp evening, Geoff Marcy will walk outside and gaze up at the San Francisco night sky where he lives. He looks at the stars, but his mind is on the millions or even billions of planets that may orbit them. The distant worlds are so far away that they cannot be seen with the naked eye, but Marcy knows they exist. He can imagine them circling their stars.

Like most people, he wonders whether any of those distant worlds are like Earth. Yet, unlike most people, he has access to the world’s best telescopes, including Keck Observatory, to help answer this question.  Marcy has led the way in discovering planets of all types beyond our Solar System, including super-hot orbs larger than Jupiter and icy balls similar in size to Neptune. With Keck, he and his fellow astronomers recently found distant worlds not much larger than Earth orbiting stars similar to our Sun. Such a discovery leads Marcy to believe that within the next few years, they will find the “holy grail” of planet hunting—another Earth.