'Mega-Earth' planet discovered

This is an artist's picture of what Kepler-10c may look like.

A brand new type of rocky planet has been discovered.

Kepler-10c is being called a 'mega-Earth' - a new type of planet that has a hard surface, like our own world, but is much, much bigger.

In fact Kepler-10c itself is thought to be about 17 times the mass of our Earth.

It orbits a star about 560 light-years away and was detected by Nasa's Kepler telescope.