Kepler is observing more than 100,000 stars at a time for signs of exoplanets. Exoplanets orbit stars other than our own sun.
However, the spacecraft’s specific mission is to search for other planets within our Milky Way galaxy, particularly those in the “habitable zone,” which have the potential to support life because they resemble Earth in regards to their size and distance from the sun.
Kepler has found over 700 confirmed exoplanets, but just discovered the three smallest exoplanets yet. Orbiting a star, KOI-961, these three new planets are rocky, and the smallest is about the size of Mars at 0.57 times the size of Earth.
There are probably many more exoplanets in our galaxy, based on a new statistical study from NASA. According to the study, there is, on average, at least one planet for every star in the galaxy.
Since there are about 100 billion stars in the Milky Way, astronomers are saying that there are a minimum of 100 billion planets in our galaxy—perhaps adjusting our expectations of our galaxy.
The study furthermore estimates that, because scientists believe there are more Earth-like exoplanets than there are easier-to-detect Jupiter-type planets, there are about 10 billion rocky planets out there that are like Earth.
