If you want to know what scientists are thinking about, you don’t need to ask—all you need to do is count. That’s what I did as I was touring the Long Beach Convention and Entertainment Center in Long Beach, California, where the American Astronomical Society is currently holding its semi-annual meeting. I tallied meeting abstracts, scientific sessions, press conferences, and (more impressionistically) casual conversations in the pannini-and-pizza lunch area.
So what is on the mind of the world’s greatest explorers of the cosmos? By any measure, the answer comes down to one word: exoplanets.
“Exoplanet” is the technical term for any planet that does not circle the sun—or, to put it another way, any planet that lies beyond the bound of our solar system. Two decades ago, nobody was sure such worlds even existed. Twenty one years ago, almost to the day, astronomers reported the first planets around another star. Yesterday, scientists working with NASA’s space-based Kepler Observatory announced 461 new likely exoplanets, bringing the number of worlds discovered just by that one mission to 2,740. Including all the ones identified by other searches, the number is over 3,000. Stop and think about that number. From 5000 BC to AD 1992, the number of planets known to science grew just from 5 to 9. We live in the middle of an explosion of planetary knowledge, and Long Beach sits at ground zero.