Where Life Could Exist

Habitability is complex and depends on far more than distance:

• The habitable zone is where liquid water can exist on a planet's surface
• For the Sun, this spans roughly 0.95 to 1.67 AU
• Atmosphere, magnetic field, and geological activity matter just as much
• Tidal heating can warm oceans far outside the zone, as on Europa
• Coexisting oxygen and methane could flag life from light-years away

Statistical models suggest billions of rocky planets sit in habitable zones across the Milky Way. The question is no longer whether habitable worlds exist, but how many have actually grown life.