David Levy is America's "professional amateur" astronomer. A prolific author, he has penned over 30 books on popular astronomy subjects, as well as biographies of famous astronomers. He has also discovered 22 comets, 9 by himself, the rest with his collaborators Carolyn Shoemaker and her late husband, Gene. They discovered Shoemaker-Levy 9, the comet that collided with Jupiter in 1994. That episode produced the most spectacular explosions ever witnessed in the solar system.

He won an Emmy award in 1998 as part of the writing team for the Discovery Channel documentary, "Three Minutes to Impact." As the Science Editor for Parade Magazine, he is able to reach more than 80 million readers, almost a quarter of the population of the United States. A contributing editor for Sky and Telescope Magazine, he writes its monthly "Star Trails" column. He and his wife Wendee host a weekly radio show available worldwide at www.letstalkstars.com.

His talk, entitled A Time for Mars is a look at the exciting history of Mars, including Jonathan Swift's prediction of the discovery of two moons in Gulliver's Travels, Orson Welles' War of the Worlds, and the idea that life on Earth might have been seeded from Mars. Are we all Martians?

A booksigning will be held in booth #1 on the conference floor immediate following David's talk.

TIME: 11:00 AM Friday Talks 2