Latest Exoplanets Earth-Sized, But Not "Just Right"

The latest findings from NASA’s Kepler space telescope confirm rocky planets the same size as Earth orbiting a star like our Sun, but they are too close to their Sun to be able to support life as we know it.

NASA announced the most recent Kepler findings today.  The planets, designated Kepler-20e and Kepler-20f, are part of a five-planet system orbiting a star similar to our Sun in the constellation Lyra, about 1,000 light years away.

Earlier this month, NASA said that it had confirmed the existence of an Earth-sized planet around a different star that is 600 light years away.  That planet, Kepler-22b, is at the correct distance from its Sun — in the “habitable” or “Goldilocks” zone where the temperature is not too hot, not too cold, but just right — for liquid water to exist. According to current knowledge, life as we know it requires liquid water.

However, NASA said today that Kepler-22b is “likely to be too large to have a rocky surface.”    The two planets discussed today are likely to be rocky, but probably do not have liquid water, NASA said.  The search for Earth-sized, rocky planets in the habitable zone of a star like our Sun continues.

Kepler can not actually see other planets.   It collects data on the dimming of stars that suggests that other bodies — planets — are crossing (“transiting”) between the star and the telescope at regular intervals and thus are in orbit around the star.