Small planet 'is rocky like Earth'
Published 11/01/2011 | 06:01
A Nasa telescope has found the smallest planet outside our solar system and it is rocky just like Earth.
But it is too hot for any life. One side of the planet is about 2,700 degrees Fahrenheit (1,500C).
The planet is called Kepler 10-b after the telescope that found it.
Nasa scientist Natalie Batalha said the planet is about 1.4 times the size of Earth and has a mass about four-and-a-half times our planet's.
Astronomers have found other planets outside our solar system that are closer in mass to Earth, but none this small in diameter.
The reason it is so hot is that it is 20 times closer to its star than Mercury is to our sun.