Our galaxy probably contains at least two billion planets that, like Earth, have liquid water on their surfaces and orbit around their parent stars in the "habitable zone" for life. The nearest, according to astronomers, could be a mere 12 light years away.
A new study, published on Monday in the Proceedings of the National Academy of Sciences, suggests that Earth-like planets capable of supporting life are far more common than previously thought. Using measurements from Nasa's Kepler space observatory, scientists led by Erik Petigura at the University of California, Berkeley, estimated that 22% of our galaxy's sun-like stars have rocky planets circling them in the zone where they get roughly the same amount of light energy as Earth receives from the sun. There are around 100bn stars in our galaxy, of which 10% are like the sun .... http://www.theguardian.com
