Updated view of a Galileo spacecraft image of the Nicholson Regio/Arbela Sulcus region on Jupiter's moon Ganymede.
Original Image and Caption
This view of the Nicholson Regio/Arbela Sulcus region on Jupiter's moon Ganymede, taken by NASA's Galileo spacecraft, shows the stark contrast between the smooth bright terrain and the surrounding highly fractured dark terrain.
This observation was designed in part to distinguish between different models for how Arbela Sulcus and other groove lanes on Ganymede were formed. The volcanic model suggests that a relatively clean, water-rich lava filled a tectonic depression, then cooled to create a smooth surface. Tectonic models suggest that focused faulting and deformation of older dark terrain destroyed the pre-existing texture, which was brightened by exposure of underlying, clean ice. Analysis of these photos suggests a third and unexpected possibility: Arbela Sulcus may be similar to some bands on another of Jupiter's moons, Europa, formed by tectonic crustal spreading and renewal.
North is to the upper left of the picture and the Sun illuminates the surface from the west. The image, centered at 14 degrees latitude and 347 degrees longitude, covers an area approximately 160 by 72 miles (258 by 116 kilometers). The resolution is 436 feet (133 meters per picture element. The images were taken on May 20, 2000, at a range of 8,140 miles (13,100 kilometers).