Europa's icy surface is relatively smooth and has distinctive linear ridges, cracks and flows. Many scientists believe that liquid water oceans may lie beneath this outer ice layer, making Europa a place where life could exist.
Photo: Europa taken by the Galileo probe (NASA)
Jupiter's smooth moon may have subsurface oceans.
Voyager opens up the question of whether life could exist on Jupiter's moon.
The Voyager probe pictures of Jupiter's moon Europa showed scientists that the satellite's ice surface is relatively smooth and covered with linear features. They theorised that an ocean of liquid water exists below the surface and that this fluid might contain life that gets its energy from the moon's inner heat.
Images of Jupiter's moon reveal evidence of a new type of volcanism.
Images from the Galileo and Voyager missions (launched in 1989 and 1977 respectively) showed scientists that Europa is a relatively smooth icy moon with a network of fractures that may erupt liquid water from an ocean beneath the surface.
As the Sun ages, Europa will warm and may support life.
Jupiter's moon Europa will warm as the Sun ages and may support life. Scientists speculate it could become a watery world.
Jupiter's moons aren't the cold, dead worlds the experts expected.
Voyager scientists thought Jupiter's moons would be cold, dead worlds. They were amazed when the first close-up images from the spacecraft revealed four moons, each different from the next. The probes were launched in 1977.
If life can exist in solid ice on Earth, what about Europa?
Professor Brian Cox goes to caves in Iceland to find microbial life that survives in solid ice. Astrobiologists theorise that if life can live in solid ice on Earth, it may be able to survive on Jupiter's icy moon Europa
Europa i/jʊˈroʊpə/ (Jupiter II), is the sixth closest moon of the planet Jupiter, and the smallest of its four Galilean satellites, but still one of the largest moons in the Solar System. Europa was discovered in 1610 by Galileo Galilei and possibly independently by Simon Marius around the same time. Progressively more in-depth observation of Europa has occurred over the centuries by Earth-bound telescopes, and by space probe flybys starting in the 1970s.
Slightly smaller than Earth's Moon, Europa is primarily made of silicate rock and probably has an iron core. It has a tenuous atmosphere composed primarily of oxygen. This surface is striated by cracks and streaks, while cratering is relatively infrequent. The apparent youth and smoothness of the surface have led to the hypothesis that a water ocean exists beneath it, which could conceivably serve as an abode for extraterrestrial life. This hypothesis suggests that a source of heat from tidal flexing causes the ocean to remain liquid and drives geological activity similar to plate tectonics.
The Galileo mission, launched in 1989, provided the bulk of current data on Europa. Although only fly-by missions have visited the moon, the intriguing characteristics of Europa have led to several ambitious exploration proposals. The next mission to Europa is the European Space Agency's Jupiter Icy Moon Explorer (JUICE), due to launch in 2022.