The Kepler mission has discovered the first super-Earth in the habitable zone of a distant Sun-like star, according to NASA.
The newly found planet Kepler-22b is about 2.4 times the radius of Earth. Scientists don’t know if Kepler-22b has a predominantly rocky, gaseous or liquid composition, but its discovery is a step closer to finding Earth-like planets.
Artist's conception of Kepler-22b (NASA)
“This is a major milestone on the road to finding Earth’s twin,” said Douglas Hudgins, Kepler program scientist at NASA Headquarters in Washington.
Kepler-22b is located 600 light-years away. While the planet is larger than Earth, its orbit of 290 days around a Sun-like star resembles that of our world. The planet’s host star belongs to the same class as our Sun, called G-type, although it is slightly smaller and cooler.
Kepler discovers planets and planet candidates by measuring dips in the brightness of more than 150,000 stars to search for planets that cross in front, or transit, the stars. Kepler requires at least three transits to verify a signal as a planet.
