Two of the planets -- Kepler-62e and Kepler-62f -- are described in a study released Thursday in the journal Science. They are part of a five-planet system in which the candidates for life are the farthest from the host star.
Their host star -- which corresponds to Earth's sun, but is smaller and cooler -- takes the name Kepler-62. The star's planets are designated by letters after the star's name. A third planet that's potentially habitable, but not included in the Science study, is called Kepler-69c.
These are the smallest planets ever found in the "habitable zone," the area near a star in which a planet can theoretically hold liquid water. Kepler-69c seems less clearly in the habitable zone than the other two planets, but scientists haven't ruled it out.
"With all of these discoveries we're finding, Earth is looking less and less like a special place and more like there's Earth-like things everywhere," said Thomas Barclay, Kepler scientist at the Bay Area Environmental Research Institute in Sonoma, California.
You won't be swimming on the planets anytime soon, though. The Kepler-62 star is 1,200 light-years away; Kepler-69 is 2,700 light-years away. A light-year, the distance that light travels in a vacuum in one year, is nearly 6 trillion miles.