The ‘habitable zone’, also known as the ‘Goldilocks zone’, is the area around a star where conditions are just right for liquid water to exist on a rocky planet. It’s not too hot, not too cold. It is also key in the hunt for alien life, given that water is deemed necessary for life as we know it to evolve. This belt serves as a cosy home for our oceans, rivulets, and lakes in liquid form, thanks to Earth’s placement within this zone. The discovery of other planets that orbit in this habitable zone, particularly ones that are made out of rock, is currently a high priority across the planet-searching community.

NASA Explains the Goldilocks Zone: Where Planets Can Sustain Liquid Water and Life

As per NASA explanations, if Earth were shifted higher and closer in the solar system where Mercury is, surface water would start to evaporate, eventually boiling away into a steam-heavy atmosphere. If we took the Earth out to Pluto, by contrast, a permanent deep freeze would turn oceans and much of the atmosphere solid. This zone lies at the not-too-cold, not-too-hot region around a star where it receives enough stellar energy to keep water in its liquid state without causing it all to evaporate in endless heat or freeze into unyielding ice — a width that extends outward or inward depending on the size and heat output of the star.

Goldilocks Zones: Actually, this is more commonly known as a Habitable Zone. And, of course, where exactly that is depends on what kind of star you mean — cool, low-luminosity stars live much closer to the Sun and at lower temperatures; hot, high-luminosity stars shove that zone way out. A team of scientists is on the hunt for authentic exoplanets in this region.

Water is important for life on Earth and natural cosmetics. Subglacial systems influence climate and geological processes. Water signatures are important atmospheric features for exoplanet-watchers, influencing habitable assessment.

In the future, missions will search for exoplanet atmospheres and examine “biosignature” and biosphere signatures — possibly from plants — to see if life exists on habitable worlds.