Kepler_22b ocean planet, animation. This planet was discovered by the Kepler spacecraft in December 2011. It orbits the star Kepler_22, which is a Sun_like star some 600 light years from Earth, in the constellation Cygnus. Kepler_22b is notable for being within the habitable zone of the star, the distance from the star at which the planet磗 surface temperature would support the existance of liquid water. The planet is 2.4 times the diamater of the Earth. Although its mass and composition is not known with any certainty, it has been suggested that the planet may be a waterworld, or ocean planet. This is a planet with no land surface, only a very deep ocean. The cutaway shows the layers of the planet: its atmosphere is Earth_like, with clouds and similar weather. The ocean dark blue extends several hundred kilometres down, before the immense pressure forms a thick layer of exotic ices light blue, water solidified not by temperature but by pressure. Below that, the planet is more Earth_like, with a rocky mantle orange overlying the outer yellow and inner white core. NASA磗 Kepler spacecraft was launched in 2009 on a mission to hunt for Earth_like planets.