Billions of potentially habitable planets may exist in the Milky Way, according to a study.
Around 100 "super-Earths" may be found in our galaxy, at distances less than 30 light years from the sun.
Astronomers made the prediction after conducting a survey of red dwarf stars, which account for 80% of stars in the Milky Way. They think about 40% of red dwarfs have a rocky planet not much bigger than Earth orbiting the "habitable zone" where liquid surface water can exist.
Where there is water, there could be life - although being in the zone does not guarantee life has evolved on a planet.
Dr Xavier Bonfils, from Grenoble University in France, led an international team which surveyed a carefully chosen sample of 102 red dwarfs using the European Southern Observatory's 3.6-metre telescope at La Silla, Chile.
He said: "This leads us to the astonishing result there are tens of billions of these planets in our galaxy alone."
The scientists estimate there could be around 100 habitable zone planets within 30 light years.
The journal Astronomy & Astrophysics reported the research.