Research suggests planets and moons may support life further from star than previously thought
08 Jan 2014
Planets and moons might be able to support life further away from their star, at much greater than previously thought, according to research carried out in Scotland.
According to scientists, the traditional ''Goldilocks'' model of planets which could sustain life – ones that were not too hot and not too cold overlooked the fact that liquid water could exist deep below the surface.
The University of Aberdeen team, which worked with academics from the University of St Andrews, carried out computer modelling which suggested the habitable zone for an Earth-sized planet could be as much as 14 times wider than what had been earlier estimated.
They concluded that the zone would include ''many more planets'', and said it could even mean our planet was actually unusual for having its life predominantly on the surface.
The journal Planetary and Space Science has featured the research paper.
BBC News quoted lead author and PhD student Sean McMahon as explaining that the deepest known life on earth was 5.3km below the surface, but there might be life even 10km deep in places on earth that had not yet been drilled.
He said using their computer model, the researchers discovered that the habitable zone for an earth-like planet orbiting a sun-like star was about three times bigger if the top five kilometres below the planet surface was included.
McMahon explained, a planet to be needed not to be too close to its sun but also not too far away for liquid water to persist, rather than boiling or freezing, on the surface.
He added that the theory failed to take into account that life could exist beneath a planet's surface.
As one went deeper below a planet's surface, the temperature increased, and once one got down to a temperature where liquid water could exist - life too could exist there too, he said.
The team built a computer model that estimated the temperature below the surface of a planet of a given size, at a given distance from its star.
He said the model showed that liquid water could survive below the earth's surface even if the earth was three times further away from the sun than it was just now.
He added, the results suggested life might occur much more commonly deep within planets and moons than on their surfaces.
