"If we're going to be looking for planets, earth-like planets are the key," Foothill College Astronomy Department Chair Andrew Fraknoi said.
Fraknoi has loved astronomy since childhood. He says NASA's Kepler mission is one of the most exciting in quite some time.
"In the last 16 years, we've discovered over 400 planets going around other stars, but the methods so far that we have been using only allowed us to find big planets like Jupiter," Fraknoi said.
Kepler is a telescope designed to find planets orbiting other stars by looking for a break in the star light as a planet moves in front of it.
The challenge now is to find planets that are half to twice the size of the earth in the habitable zone of their stars, where it is possible that water and even life might exist.
"One of the best presents that astronomy could give the human species is the sense that we are not alone in the universe," Fraknoi said.
Rising from a sea of gas and dust, the Horsehead Nebula is one of the most photographed objects in the sky. But Fraknoi says Kepler has already made important discoveries, they are just not so well known.
"It's possible that Kepler will report already, just in these first six months of its operation, on the discovery of a few new planets around other stars; they may not yet be Earths, but they will demonstrate that Kepler has exactly the capability we wanted to build into it, which was rapid and interesting discoveries being made all the time from watching these 100,000 stars," Fraknoi said. "I think that it would be perhaps the most exciting discovery in the history of the human race, to know that there are other intelligent creatures out there, thinking about the universe the way that we are. The Kepler Mission is one step in that quest."
Kepler will spend 3.5 years surveying more than 100,000 sun-like stars.