📖 About Europa

Europa is the smallest of Jupiter’s four Galilean moons, discovered by Galileo Galilei in 1610. With a diameter of 3,122 km, it is slightly smaller than Earth’s Moon. Europa orbits Jupiter every 3.5 days at a distance of about 671,000 km, locked in a gravitational dance with Io and Ganymede through orbital resonance.

Beneath Europa’s smooth ice shell—estimated at 10 to 30 km thick—lies a global saltwater ocean containing roughly twice the volume of all Earth’s oceans combined. Tidal heating from Jupiter’s immense gravity keeps this ocean liquid and may drive hydrothermal vents on the seafloor. The surface features “chaos terrains” and crisscrossing ridges called lineae, evidence of active geological processes reshaping the ice.

NASA’s Europa Clipper spacecraft launched in October 2024 and will arrive at Jupiter in 2030. Over 49 close flybys, it will use ice-penetrating radar, a magnetometer, and mass spectrometers to characterize the ice shell, confirm the ocean, and search for conditions suitable for life. ESA’s JUICE mission will also make two Europa flybys in the early 2030s.

🔭 Key Features

🔬 Science & Future

Europa is considered the most promising place in our solar system to search for present-day extraterrestrial life. Its subsurface ocean has all three ingredients for life as we know it: liquid water, chemical energy from tidal heating, and organic chemistry from interaction with the rocky seafloor. The detection of hydrogen peroxide on the surface suggests oxidants could be delivered to the ocean.

Future missions beyond Europa Clipper may include a lander to directly sample the surface ice and search for biosignatures. Concepts for a “tunnelbot” to melt through the ice shell have been studied. Europa’s ocean represents one of humanity’s best chances of answering the question: are we alone in the universe?

📜 Discovery & Exploration

Galileo Galilei discovered Europa on January 8, 1610, along with Io, Ganymede, and Callisto. These four “Galilean moons” provided crucial evidence for the Copernican model of the solar system. Europa is named after a Phoenician princess in Greek mythology who was abducted by Zeus.

NASA’s Galileo spacecraft (1995-2003) provided the first detailed observations, detecting Europa’s induced magnetic field—strong evidence for a conducting subsurface ocean. The Hubble Space Telescope later observed possible water plumes erupting from the south pole. Europa Clipper represents the most ambitious mission yet to this enigmatic world.