Astronomers say there could be billions of Earths in our galaxy, the Milky Way.
Their assessment comes after the discovery of the 100th exoplanet – a planet that circles a star other than our own.

The latest find is a gas giant, just like all the other exoplanets so far detected, and orbits a Sun-like star 293 light-years away.

With about 300 billion stars in our galaxy, there could be about 30 billion planetary systems in the Milky Way alone; and a great many of these systems are very likely to include Earth-like worlds, say researchers.