The first confirmed exoplanet that sits just the right distance away from its star to enable the possibility of liquid water on its surface has been announced by NASA’s Kepler Mission.
Kepler-22b lies in a ‘goldilocks’ zone and has a radius about 2.4 times the size of that of Earth, making it the smallest exoplanet yet to be found orbitting in the ‘habitable’ zone around a star similar to our Sun, and therefore an ideal candidate as an Earth-like ‘twin’ – though scientists don’t yet know whether its surface is of liquid, gas, or solid.
The fact that this is a potentially habitable planet makes this news so incredibly exciting; and this could be just the first of around 50 exoplanets that Kepler scientists have been observing that fit the bill of being Earth-like and therefore habitable.
Kepler hunts for these potential planets by measuring dips in the brightness of light from stars as objects pass in front (transit) them.
Kepler is fixed in watching an area within the Summer Triangle asterism comrised of the bright stars vega, deneb and altair, that you can easily find stargazing on a clear night in the northern hemisphere for much of the year.