The Habitable Zone: Where Could Life Exist in Our Solar System?

The habitable zone is the region around a star where liquid water could exist on a planet surface. In our solar system, it roughly spans from Venus orbit to Mars orbit, with Earth in the middle. But life might exist elsewhere: Europa and Enceladus have subsurface oceans with hydrothermal activity.

Titan has liquid methane lakes and complex organic chemistry. Mars once had rivers and lakes. Even Venus upper atmosphere has conditions where microbial life could theoretically survive.

The search for life now extends far beyond the traditional habitable zone..