A recent episode of NPR's "This American Life" briefly explored the nonexistent love lives of graduate school physics students. In fantastically nerdy fashion, the students created a mathematical equation to determine how many potential girlfriends awaited them in Boston. They factored in such variables as the city's female population, acceptable age range and education. This approach closely followed the strategy behind the Drake equation, by which SETI scientists try to estimate how many technologically advanced civilizations currently exist in the galaxy.
Earthlings are basically looking for the same thing any lonely grad student yearns for: something we can relate to outside of ourselves. SETI strives to detect radio leakage from other intelligent civilizations, just as a MySpace user might click on "Dr. Who" in his or her favorite TV show list to see other fans.
Curiously enough, our efforts to find extraterrestrial life are largely analogous to the desperate attempt to meet strangers in a crowded bar. We've worn our Dalek T-shirt to the local pub by sending golden plaques and records beyond the solar system aboard Pioneer 10 and 11, as well as the Voyager mission. So far, no one has offered to buy us a drink.
Just as a human on the prowl would find much of the world un-dateable, so too many of the planets out there are incapable of supporting life as we know it due to such factors as size or temperature. The challenge is to figure out which spheres are most lifelike to better understand our chances, as well as to figure out where to focus. One bar patron may seem too nerdy, another not nerdy enough. One planet may be a barren rock, the other a gaseous hell world.
Today, Earth still continues to wear its Dr. Who T-shirts and scan the crowd for like interests, but the hunt for extraterrestrial life has largely become one of mapping the planets. We look for the telltale gravitational effects of planets on distant stars and NASA's upcoming Kepler mission will sort stars by size and habitable orbit.
Further off, the Terrestrial Planet Finder (TPF) program will sift through these findings for the worlds capable of supporting life. These missions will use spectroscopy, which involves analyzing an object's light to determine its physical properties, such as the presence of carbon dioxide and water. Think of it as scanning the crowd for people who look dateable and then looking even closer for wedding rings.
Will our planet find love in our lifetime? What do you think?