In search of Earth's twin

For the last 20 years, UC Berkeley astronomer Geoff Marcy has been the world's leading planet finder. Of the 260-odd planets that have been discovered in other solar systems, Marcy and his team have found 150. His most recent discovery, announced last week, is a fifth planet orbiting a star called 55 Cancri, about 41 light-years from Earth. Marcy, 53, sat down in his office to talk about the friendly and not-so-friendly competition to find the first Earth-like planet that could harbor life.

By John Johnson Jr.

November 17, 2007