Next month NASA will launch the new Kepler Telescope and the goal is an ambitious one. We’re finally going to start the process of identifying stars with potentially Earth-like planets orbiting them. According to projections at a recent conference, they might not be as rare as once thought.

There could be one hundred billion Earth-like planets in our galaxy, a US conference has heard.

Dr Alan Boss of the Carnegie Institution of Science said many of these worlds could be inhabited by simple lifeforms.

“Not only are they probably habitable but they probably are also going to be inhabited,” Dr Boss told BBC News. “But I think that most likely the nearby ‘Earths’ are going to be inhabited with things which are perhaps more common to what Earth was like three or four billion years ago.” That means bacterial lifeforms.

Thus far we’ve detected over 300 planets orbiting other stars by using the “wobble” method, where we observe variations in a star’s rotation caused by the presence of a nearby planet. Unfortunately, that only detects massive, gas giant planets similar to Jupiter which don’t hold much promise for life as we recognize it. The Kepler telescope will measure the light coming from stars similar to our own sun and detect minor fluctuations as smaller planets pass in front of them, casting a shadow as they go by. From this information, astronomers will be able to determine the size of the planet, its distance from the star and its period of orbit.

Assuming that Dr. Boss is correct and Earth-like planets are nearly as common as pennies, are we going to find intelligent life? We won’t know until we try. But if nothing else, it should help identify stars with the most promising candidates so that SETI can focus on them for long-period, broad-band observations. Once Kepler goes online we may be taking the next big step toward letting E.T. phone home.