Kepler 22-b is 600 light-years away and is about two and a half times the size of earth, with a comfortable temperature of around 22 degrees. It is not know if the planet is made of rock, water or gas. 

NASA’s Kepler team use a space telescope to study the night sky, concentrating on no fewer than 150,000 planets. Kepler 22-b is the closest planet to be found like ours – described as an ‘Earth 2.0”

Kepler 22-b lies about 15% closer to its sun than Earth does to ours, its year is about 290 days in duration and its sun puts out about 25% less light which creates its comfortable temperature, which in turn would – theoretically – support the existence of water. 

The Kepler team have spotted around 1,094 new ‘candidate’ planets that could fall under the ‘habitable zone’ – capable of supporting water.

The Kepler telescope detects its planets by scanning the night sky and seeing when a planet passes in front of its host star, dimming the light it emits by a tiny amount. These changes in light identify ‘candidate planets’, 54 of which were reported in February of this year. 

The Kepler team though had to wait for three passes of 22-b past its sun for them to be able to update its status from ‘candidate’ to ‘confirmed’. 

Kepler principal investigator at NASA’s Ames Research Centre William Borucki said of the discovery: “Fortune smiled upon us with the detection of this planet. The first transit was captured just three days after we declared the spacecraft operationally ready. We witnessed the defining third transit over the 2012 holiday period.”

Image credit: NASA/Ames/JPL-Caltech