A Super Earth is a planet smaller than Neptune, but larger than Earth. There are no Super Earths in our solar system. But they may be the most common type of planet in our galaxy, according to data from the Kepler Space Telescope. Some have rock or ice cores wrapped in hydrogen and helium gas. Others are solid rock covered in water or ice, or flowing lava.

The planet HD189733b may become a Super Earth. This gas giant orbits its parent star at 1/30th the distance between Earth and the Sun. A flare from the star blasted its atmosphere, sending a plume of gas flying into space at a rate of 1000 tons per second.

GJ 1214b, orbiting a star 40 light years away, has a mass 6 times that of Earth. It is surrounded by an atmosphere of steam or thick haze.

HD 85512b is 3.6 times the mass of Earth. It orbits a sun-like star and lies at the edge of the habitable zone. Liquid water, and perhaps even life, could exist on its surface. Gliese 667 is a triple star system. The fainter of the three, 667C, has been found to host three Super Earths, all within the life zones of their parent star. 667Cc is 4 times the mass of Earth. But it’s so close that it’s likely exposed to deadly flares, x-ray and ultraviolet radiation.

Kepler 10 is a Sun-like star 564 light years from Earth. Kepler 10b is a rocky planet more than three times the mass of Earth. It’s so close to its star that its orbit lasts only 19 hours. With a density similar to iron, its surface is molten.

Kepler 62 is a star 1200 light years away. Slightly smaller and cooler than our Sun. Of five known planets around this star, Kepler 62e orbits the inner edge of the habitable zone. At 1.6 times the mass of Earth, 62e is probably solid. It could be terrestrial or water-ice dominated. Kepler 62f lies within the habitable zone. At 2.8 times the mass of Earth, it is probably rocky and covered by ocean or ice.