Joshua Winn, Massachusetts Institute of Technology
The origin of planets is a venerable problem, dating back to Kant and Laplace, who argued that the solar system formed from a spinning disk of gas and dust. Yet it was only in 1995 that astronomers began finding planets that orbit ordinary stars other than the Sun ("exoplanets"). Finally it has become possible to learn whether our solar system is typical, or unusual, in the context of our entire galaxy.
This topic is interesting on many levels. As a physicist, one wants to understand how matter accumulates into planets, and what is the full range of possible outcomes. Some of the newfound planetary systems have striking unanticipated properties: planets on very eccentric orbits, and giant planets hugging their stars much closer than Mercury does the Sun. From a technological point of view, planet detection is a challenging problem that motivates fascinating and ambitious solutions. And finally, it would be wonderful to make even slight progress on the age-old question of whether there are other planets capable of supporting life.
My goals for this presentation are to explain how the 300+ exoplanets have been discovered, describe their properties and how the knowledge of these properties has revitalized the theory of planet formation, and discuss the prospects for discovering truly Earthlike planets.