Probe image shows Europa's icy, fractured terrain

WASHINGTON, May 11 (UPI) -- Scientists at the European Space Agency are reconsidering an old picture of Europa as they plan a future mission to the Jovian system -- Jupiter's system of moons.

The image from NASA's Galileo probe showcases the fragmented, icy surface of Europa, Jupiter's sixth-closest moon. It is a combination of shots from the probe's 1996 and 1997 missions, revealing what astronomers call "chaos terrain."

Chaos terrain is an astronomical term for alien surfaces featuring ridges, cracks and plains that haphazardly abut one another. Chaos terrain often resembles shattered glass, or a frozen puddle that's been cracked by pedestrians. Europa, Mars and Mercury all commonly feature chaos terrain.

The portion of Chaos terrain imaged by Galileo is called Conamara Chaos. In addition to its jagged appearance, the terrain is also marked by a number of small craters -- the result of clumps of ice thrown up by the large impact that created Pwyll, a large nearby crater.

The Pwyll impact is also responsible for the unique coloration of Conamara Chaos -- icy shades of blue are juxtaposed with the browns of minerals dislodged and propelled by the collision.

Scientists aren't entirely certain what causes chaos terrain in general. In the case of Europa, the frozen water beneath the moon's brittle crust seems to make the lunar surface especially susceptible to fragmentation. Some researchers say the jagged terrain is not the result of lunar impacts, but of the movements of subsurface lake systems.

The only way to find out for sure, researchers say, is to land a probe directly on Europa. The European Space Agency plans to do just that in the coming decades. Its Juice mission is set to launch in 2022 and begin exploring Jupiter's moons by 2030.