Europa. Two Galileo spacecraft images of Europa, one of Jupiter's four Galilean moons. The image on the left shows Europa, which is about the same size as Earth's Moon, in natural colours. The right image has been processed to enhance colour differences: ice containing rocky material is dark brown; fine-grained ice is light blue; coarse- grained ice is dark blue. The surface of Europa is marked by fractures that can be over 3000 kilometres (km) long. The bright area at lower right in each image is the Pwyll impact crater. These images of Europa's trailing hemisphere were taken by Galileo's Solid State Imaging System on 7 September 1996 at a range of 677,000 km.