What is Europa?
Europa is one of Jupiter's four largest moons. Its icy surface likely covers a global ocean of salty liquid water, making it one of the best places to search for life beyond Earth.
Europa is slightly smaller than Earth's Moon. Its bright surface is made of water ice crisscrossed by cracks and ridges, with very few craters, which suggests it is geologically young. Scientists think the ice shell is about 15 to 25 kilometers thick, with an ocean beneath that may be up to 100 kilometers deep.
Europa's ocean may contain about twice as much water as all of Earth's oceans combined. It stays liquid because of tidal heating: Jupiter's powerful gravity stretches and squeezes the moon as it orbits. Hubble observations have suggested possible plumes of water vapor rising from the surface.
Europa Clipper
NASA's Europa Clipper spacecraft launched in October 2024 and is due to arrive at Jupiter in 2030. It will fly past Europa dozens of times to study its ice, ocean and chemistry. The European Space Agency's JUICE mission will also study Europa.
Did You Know?
Europa was discovered by Galileo Galilei in 1610, along with Io, Ganymede and Callisto, now known as the Galilean moons.