Goldilocks Zone is a habitable zone around the star where the temperature is neither too hot nor too cold – an atmosphere required for liquid water to exist on a planet. In other words, it is an area in which a planet is at the right distance from a star to sustain liquid water. The planet Earth is in the Goldilocks Zone of the Sun.
The concept of habitable zones was first introduced in 1959 by Su-Shuang, an American Astrophysicist. Based on the data collected by NASA’s Kepler Space Observatory and W.M Keck Observatory, scientists estimated that 22% of the stars in the Milky Way Galaxy have Earth-sized planets in their habitable zone.