Announced on July 23, 2015, planet Kepler-452b is larger than Earth and orbits a star nearly identical to the sun, but older and therefore hotter. The planet's orbit is nearly the same as Earth's, and its year is about 20 days longer than Earth's. Kepler-452b is 1,400 light-years away.
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Between 15 and 25 percent of sunlike stars seem to have Earth-size planets. Smaller rocky planets like Earth (as opposed to gas-giant planets and other types) appear to be common in the Milky Way galaxy.
Exoplanet Kepler 452b: Closest Earth Twin in Pictures
The instruments on the Kepler Space Telescope search a wedge-shaped area of the Milky Way about 3,260 light-years long and oriented along the spiral arm in which our solar system is located. Another space probe, called Gaia, is tasked with precisely measuring the position, distance and motion of 1 billion stars in the Milky Way galaxy. Also to be measured will be the orbits and masses of 1,000 extrasolar planets. Gaia's first report is expected in 2016.
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