In a building at NASA’s Ames Research Center here, computers are sifting and resifting the light from 156,000 stars, seeking to find in the flickering of distant suns the first hints that humanity is not alone in the universe.
The stars are being monitored by a US$600 million satellite observatory named Kepler, whose job is to conduct a kind of Gallup poll of worlds in the cosmos. Tomorrow, Kepler’s astronomers are scheduled to unveil a closely kept list of 400 stars that are their brightest and best bets so far for harboring planets, some of which could turn out to be the smallest and most Earth-like worlds discovered out there to date. They represent the first glimpse of riches to come in a quest that is as old as the imagination and as new as the iPad.
Over the next two or three years, as Kepler continues to stare and sift, astronomers say, it will be able to detect planets in the “Goldilocks” zones, where it is neither too hot nor too cold for liquid water.
“What we want is to find life,” said Geoffrey Marcy, an astronomer at the University of California, Berkeley, who is part of the Kepler team.
William Borucki, 72, the lead scientist, who has spent the last 20 years getting Kepler off the ground, said recently in an interview in his office: “I’ve argued that Kepler is more important than the Hubble Space Telescope. We provide the data mankind needs to move out into space.”
These are science-fiction times. Kepler is only the first step in a process that experts agree will take decades. Both NASA and the European Space Agency have laid plans for a multidecade quest — employing ever more sophisticated and expensive spacecraft — for planets and life beyond Earth.
A roving robot laboratory named Curiosity will depart for Mars on a US$2.5 billion mission this fall. Astronomers argue whether the next such mission should go to Jupiter’s moon Europa, with its subsurface ocean; Saturn’s moon Titan, which is coated with a methane slush; or another of Saturn’s moons, Enceladus, which is spouting geysers of water from its interior.
Right now, humans cannot even summon the money or political will to get back to the moon, let alone set sail for another star. It would take 300,000 years for Voyager 1, now on the way out of the solar system at 62,764kph, to travel the 20 light-years to Gliese 581, one of the nearest planetary systems; Kepler’s planets are from 500 to 3,000 light-years away. NASA and other organizations, like the Planetary Society, have experimented with devices like solar sails, in which a craft is pushed by sunlight or a powerful laser, and ion drives, in which high-energy particles do the propelling.
This is more than just an intellectual exercise, scientists say. Traditional religious images of ourselves as God’s creatures, or even of God, could be in for a rough time if we ever discover pond scum living by completely alien chemical rules on some moon or planet, let alone the Borg — the alien race ruled by a collective mind on Star Trek — inhabiting some distant realm.
Moreover, as astronomers keep reminding us, humanity will eventually lose Earth as its home, whether because of global warming or the ultimate plague or a killer asteroid or the sun’s inevitable demise. Before then, if we want the universe to remember us or even know we were here, we need to get away.