Astronomers have now discovered more than 250 planets orbiting other stars. Hear the scientist who has discovered more planets than anyone else in the history of the world discuss what kinds of planets we have found so far, and what a new generation of telescopes might find in the future. Could discoveries of planets that resemble the Earth spark a new era when we could someday begin communication with alien life? Dr. Geoff Marcy won the Shaw Prize (one of the highest honors in science) in 2005 and was Discover Magazine's Space Scientist of the Year. He and his co-workers pioneered the technique for finding planets around other stars without seeing light from the planet (by looking for wiggles in the motion of the star each planet orbits.) Recorded March 5, 2008.