Reddish spots and shallow pits pepper the enigmatic ridged surface of Europa in this view combining information from images taken by NASA's Galileo spacecraft during two different orbits around Jupiter.

The spots and pits visible in this region of Europa's northern hemisphere are each about 10 kilometers (6 miles) across. The dark spots are called "lenticulae," the Latin term for freckles. Their similar sizes and spacing suggest that Europa's icy shell may be churning away like a lava lamp, with warmer ice moving upward from the bottom of the ice shell while colder ice near the surface sinks downward. Other evidence has shown that Europa likely has a deep, melted ocean under its icy shell. Ruddy ice erupting onto the surface to form the lenticulae may hold clues to the composition of the ocean and to whether it could support life.

The image combines higher-resolution information obtained when Galileo flew near Europa on May 31, 1998, during the spacecraft's 15th orbit of Jupiter, with lower-resolution color information obtained on June 28, 1996, during Galileo's first orbit.

enigmatic
Adjective

mysterious or puzzling.

erupt
Verb

to explode or suddenly eject material.

Europa
Noun

moon of Jupiter.

Noun

half of a sphere, or ball-shaped object.

Noun

water in its solid form.

Jupiter
Noun

largest planet in the solar system, the fifth planet from the Sun.

Latin
Noun

language of ancient Rome and the Roman Empire.

lenticula
Noun

(plural: lenticulae) dark, reddish-colored spot visible on Jupiter's moon Europa.

NASA
Noun

(National Aeronautics and Space Administration) the U.S. space agency, whose mission statement is "To reach for new heights and reveal the unknown so that what we do and learn will benefit all humankind."

Noun

large body of salt water that covers most of the Earth.

orbit
Noun

path of one object around a more massive object.

Noun

any area on Earth with one or more common characteristics. Regions are the basic units of geography.

spacecraft
Noun

vehicle designed for travel outside Earth's atmosphere.