Researchers have claimed that Earth-sized planets that are at least 10 times further away from stars could support life.
The University of Aberdeen team, which included academics from the University of St Andrews, said cold rocky planets thought uninhabitable might be able to support life beneath the surface, the BBC reported.
PhD student Sean McMahon said that a planet needs to be not too close to its sun but also not too far away for liquid water to persist, rather than boiling or freezing, on the surface.
The team created a computer model that estimates the temperature below the surface of a planet of a given size, at a given distance from its star.
Using the computer model the researchers discovered that the habitable zone for an Earth-like planet orbiting a sun-like star is about three times bigger if they include the top five kilometres below the planet surface.
The results suggest life may occur much more commonly deep within planets and moons than on their surfaces.
The research is published in Planetary and Space Science.
