The habitable zone, or the “goldilocks zone” as it’s often known (not to close to the star, not too far away), is the orbital range where it’s possible for liquid water to exist. Thus, it’s the range where life as we know it could feasibly take root. The planet-hunting Kepler is designed specifically to seek out planets orbiting distant stars, and thus far its been a boon for exoplanetary science.
In 136 days it has scanned some 150,000 target stars looking for the signature wobble exerted on those stars by orbiting satellites. In doing so, it has found 1,235 potential planets.
One analysis has predicted that one-third of ‘sun-like’ stars – stars with the classification F, G or K – will have planets similar to Earth.
Dr. Wesley Traub, Chief Scientist with NASA’s Exoplanet Exploration Program says, ‘About one-third of FGK stars are predicted to have at least one terrestrial, habitable-zone planet.’
Traub used statistical analysis to ‘predict’ planets that had not been detected by Kepler, and whether they would be within the ‘habitable zone’ around their stars.
His analysis hints that there may be even more potential ‘Earths’ orbiting them than previously thought – and that this ‘principle’ would extend to stars not yet scanned by Kepler.