Water is abundant in our solar system

Liquid water is no longer a luxury exclusive to Earth. Thanks to decades of planetary exploration, scientists now know that our solar system is awash in it, with vast hidden oceans existing as subsurface seas, ancient riverbeds, and even fleeting flows.

The Inner Solar System: Fleeting and Ancient Flows

While the inner planets are mostly dry today, both Earth and its neighbors show signs of abundant water. Earth: The only world in our system with stable, flowing liquid water on its surface, which covers roughly 71% of the globe.

Mars: The Red Planet was once a wet world with lakes and rivers. While it is now a freezing desert, observations of dark, recurring streaks on slopes during warm seasons suggest that briny, salty water may still seep across the Martian surface today.

The Outer Solar System: Worlds of Hidden Oceans

The most voluminous liquid water in our solar system doesn't sit on the surface, but rather sloshes in immense, dark oceans buried miles beneath thick shells of ice.

Jupiter's Moon Europa: Planetary models suggest Europa's subsurface ocean could contain more than twice as much water as all of Earth's oceans combined. The global ocean is heated by tidal forces from Jupiter, keeping it in a liquid state.

Saturn's Moons: Enceladus famously erupts with massive geysers of water vapor and ice grains from its south polar region, proving a subsurface ocean is actively venting into space.

Further out, Saturn's massive moon Titan also harbors a deep, salty water ocean beneath its icy crust, underneath its surface rivers and lakes of liquid methane.

Why Liquid Water Matters

Water (H{2O) is a prerequisite for life as we know it, acting as the ultimate chemical solvent that hosts the interactions of organic molecules. Discovering these vast, hidden reservoirs beyond Earth-often warmed by geothermal activity or tidal forces-expands the list of potential locations capable of supporting microscopic life in our cosmic neighborhood

The Cassini space probe showed that liquid water existed in the solar system beyond Earth. The James Webb Space Telescope is increasing our knowledge about these icy moons and is studying exoplanets in other solar systems looking for signs of water there as well.