An artist's conception of the 6-planet system of Kepler 11
This is absolutely stunning! Kepler mission has so far detected 1235 candidate planets (see here for details on how Kepler detects planets). Out of these, 68 are the size of the Earth! Wait. This is not all. Astronomers usually get more excited to find planets orbiting in the habitable zone of the star. This is the distance at which water can stay in liquid form. For our Solar system, Earth and Mars are in the habitable zone (though Mars is right at the edge). We think if there is liquid water, then there is a good chance there is life there as well.
Well, Kepler has found 54 candidates in the habitable zone - and 5 of these are close to the size of the Earth. Wow!
Oh wait. And Kepler also has a confirmed detection of a planetary system, Kepler 11, with at least 6 planets orbiting the parent star. This is located about 2000 light years away and is a weird system (at least weird for us - and we are weird for the aliens living on these planets) as all six planets have orbits smaller than Venus, with five orbiting even closer than our Mercury. Very cool!
If you are a betting person, I would advise against betting your house against astronomers finding signatures of life within the next 10-15 years. Most likely, it is going to be through spectroscopy of the atmospheres of one of the small earth-sized planets located in one of the habitable zones. Then the discussion will quickly shift to: Oh there is no way there can be complex life forms out there. Hmm...well just a wait a bit more.
Read the Kepler press release here.