Finding Other Earths
When I was a graduate student, not that long ago (it seems), there were no confirmed worlds orbiting other stars. Now there are over 100. Most of these are larger than Jupiter and frequently closer to their stars than Mercury is to the Sun. Both factors make these strange new worlds intriguing, but inhospitable to say the least. New telescopic missions on the horizon, such as the Kepler mission, promise to expand our list of distant planets to include Earth-like worlds. In the meantime, a study of a multi-planet system suggests that one of its planets may be habitable: not too warm, not too cold, and with a solid surface beneath a reasonable atmosphere. Sean Raymond, whose office is just next door to mine, participated in this study and does computer simulations of the formation of habitable planets around other stars. While his research suggests that only a small fraction of the currently discovered extra-solar planetary systems may have habitable planets, the total number in the Milky Way, even in our neck of the woods, could still be, well, astronomical.