( CNN ) -- For more than a year , the spacecraft Kepler has been combing the vastness of space looking for Earth-like planets . On Thursday , NASA scientists will share news of what they are calling the `` discovery of an intriguing planetary system . '' Since its launch on March 6 , 2009 , the space observatory has recorded tiny blips from more than 150,000 stars . If a planet happens to cross -- or transit -- in front of a star , the star dims in brightness . That is how Kepler determines it may have come across a planet . In June , NASA announced that the space observatory had identified more than 700 planet candidates , including five solar systems that had more than one transiting planet . But scientists need to examine further to make sure it is indeed a planet that is crossing in front of a star , and not another orbiting star .
The Kepler spacecraft has been observing stars from 150,000 stars . The stars dim in brightness if a planet passes in front of them . So far , it has identified more than 100 planet candidates .