The frozen Ocean of Europa

This complex area on the side of Europa which faces away from Jupiter shows several types of features that are formed by disruptions of Europa's icy crust. North is to the top of the image, taken by NASA's Galileo spacecraft, and the Sun illuminates the surface from the left. The prominent wide, dark bands are up to 20 Km (about 12 miles) wide and over 50 Km (appx. 30 miles) long. They are believed to have formed when Europa's icy crust fractured, separated and filled in with darker, "dirtier" ice or slush from below. A relatively rare type of feature on Europa is the 15-Km-diameter (about 9,3-mile) impact crater in the lower left corner. The small number of impact craters on Europa's surface is an indication of its relatively young age. A region of chaotic terrain south of this impact crater contains crustal plates which have broken apart and rafted into new positions. Some of these "ice rafts" are nearly 1 Km (about 1/2 a mile) across.
Other regions of chaotic terrain are visible and indicate heating and disruption of Europa's icy crust from below. The youngest features in this scene are the long, narrow cracks in the ice which cut across all other features. One of these cracks is about 30 kilometers (18 miles) to the right of the impact crater and extends for hundreds of miles from the top to the bottom of the image.