NASA astronomers have "discovered the first Earth-sized planet outside the solar system that has a rocky composition like that of Earth."

Planet Kepler-78b orbits its host star every 8.5 hours, making it a blazing inferno and not suitable for life. Its star is "slightly smaller and less massive than the sun."

Located at 400-lightyears from us, earth's hell of a twin is in the constellation Cygnus.


Image: An artist's concept of the Kepler-78b

According to NASA, Kepler-78b is 1.2 times the size of Earth and 1.7 times more massive, resulting in a density that is the same as Earth's. This suggests that Kepler-78b is also made primarily of rock and iron.

[NASA]