One of Jupiter's large moons, with a global ocean of liquid water below its icy crust.
Europa is slightly smaller than our Moon. Its surface is made of water ice, criss-crossed by long cracks and ridges, and it has very few craters, which means the surface is young.
A hidden ocean
Measurements by the Galileo spacecraft showed that Europa most likely has a global ocean of salty liquid water below its icy crust, with more water than all of Earth's oceans. Tidal forces from Jupiter keep the ocean from freezing.
Because liquid water, chemistry and energy may all be present, Europa is one of the best places to look for conditions suitable for life beyond Earth.
Europa Clipper
NASA's Europa Clipper spacecraft was launched in October 2024 and is planned to reach Jupiter in 2030. It will fly past Europa dozens of times to study its ice shell and ocean.