Europa
Europa is an icy world that hides a global ocean beneath its frozen crust. It is considered one of the most promising places in the solar system to search for life.
Europa is the smallest of the Galilean moons, slightly smaller than Earth’s Moon. But don’t let its size fool you—it is one of the most intriguing worlds in our solar system.
The Hidden Ocean
The most exciting feature of Europa is what lies beneath its surface. Scientists are almost certain that Europa harbors a global ocean of salty liquid water beneath its thick shell of ice. This ocean could contain more than twice as much water as all of Earth’s oceans combined.
Like Io, Europa’s interior is kept warm by tidal heating from Jupiter. This heat keeps the ocean liquid and could drive hydrothermal vents on the seafloor—environments that on Earth are teeming with life.
Icy Surface
Europa has the smoothest surface of any known solid object in the solar system. It has very few craters, indicating that its surface is young and constantly being reshaped by tectonic activity. The moon is crisscrossed by dark reddish-brown lines called lineae, which are cracks in the ice where warmer material from below has welled up.
Exploration
NASA’s upcoming Europa Clipper mission will orbit Jupiter and perform multiple close flybys of Europa to study its ice shell and subsurface ocean, looking for signs that this icy moon could support life.