Dr. Emily Rice
American Museum of Natural History
7:30 pm Room 001 ESS Building
Friday, February 4, 2011

What is a Planet?

For thousands of years the definition of a "planet" was straightforward: planets wandered among the apparently fixed stars in the night sky. Since 1801, many astronomical discoveries have changed the answer to the question "What is a planet?" both inside and outside the Solar System. Inside the Solar System, a clear and precise definition of "planet" can help us understand the structure and formation of our particular planetary system. Outside the Solar System, finding planets around other stars and distinguishing them from other astronomical objects can be a tricky task. In particular, objects called brown dwarfs blur the boundary between star and planet. Understanding planets and their impostors will bring us closer to answering the question "Are we alone in the Universe?".

I will describe the current astronomical understanding of planets within and beyond the Solar System, including major discoveries of the last 200 years. I will also explain ongoing observations and possible results to watch for in the next several years that could either further change or finally solidify our understanding of "What is a planet?".

Dr. Emily Rice is an astronomer at the American Museum of Natural History in New York City. A native of Rochester, NY, she finished her Ph.D. at UCLA and returned the east coast in 2009. Her research focuses on very low mass stars, brown dwarfs, and extra-solar planets.