This picture is part of the highest-resolution Voyager 2 imaging sequence of Ariel, a moon of Uranus about 1,300 kilometers (800 miles) in diameter. The clear-filter, narrow-angle image was taken Jan. 24, 1986, from a distance of 130,000 km (80,000 mi). The complexity of Ariel's surface indicates that a variety of geologic processes have occurred. The numerous craters, for example, are indications of an old surface bombarded by meteoroids over a long period. Also conspicuous at this resolution, about 2.4 km (1.5 mi), are linear grooves (evidence of tectonic activity that has broken up the surface) and smooth patches (indicative of deposition of material). The Voyager project is managed for NASA by the Jet Propulsion Laboratory.

Voir l'image PIA00037: Ariel at Voyager Closest Approach sur le site de la NASA.

PIA01351: Bright patches on Ariel

Distinct bright patches are visible on Ariel, the brightest of Uranus' five largest satellites. Voyager 2 obtained this image Jan. 22, 1986, from a distance of 2.52 million kilometers (1.56 million miles). The clear-filter image, obtained with the narrow-angle camera, shows a resolution of 47 km (29 miles). Ariel is about 1,300 km (800 mi) in diameter. This image shows several distinct bright areas that reflect nearly 45 percent of the incident sunlight; on average, the satellite displays a reflectivity of about 25-30 percent. The bright areas are probably fresh water ice, perhaps excavated by impacts. The south pole of Ariel is slightly off center of the disk in this view. Voyager 2 will obtain its best views of the satellite on Jan. 24, at a closest-approach distance of 127,000 km (79,000 mi). The Voyager project is managed for NASA by the Jet Propulsion Laboratory.

Voir l'image PIA01351: Bright patches on Ariel sur le site de la NASA.

PIA01356: Ariel's transecting valleys

This highest-resolution Voyager 2 view of Ariel's terminator shows a complex array of transecting valleys with super-imposed impact craters. Voyager obtained this clear-filter, narrow-angle view from a distance of 130,000 kilometers (80,000 miles) and with a resolution of about 2.4 km (1.5 mi). Particularly striking to Voyager scientists is the fact that the faults that bound the linear valleys are not visible where they transect one another across the valleys. Apparently these valleys were filled with deposits sometime after they were formed by tectonic processes, leaving them flat and smooth. Sinuous rilles (trenches) later formed, probably by some flow process. Some type of fluid flow may well have been involved in their evolution. The Voyager project is managed for NASA by the Jet Propulsion Laboratory.

Voir l'image PIA01356: Ariel's transecting valleys sur le site de la NASA.

PIA00041: Ariel - Highest Resolution Color Picture

The complex terrain of Ariel is viewed in this image, the best Voyager 2 color picture of the Uranian moon. The individual photos used to construct this composite were taken Jan. 24, 1986, from a distance of 170,000 kilometers (105,000 miles. Voyager captured this view of Ariel's southern hemisphere through the green, blue and violet filters of the narrow-angle camera; the resolution is about 3 km (2 mi). Most of the visible surface consists of relatively intensely cratered terrain transected by fault scarps and fault-bounded valleys (graben). Some of the largest valleys, which can be seen near the terminator (at right), are partly filled with younger deposits that are less heavily cratered. Bright spots near the limb and toward the left are chiefly the rims of small craters. Most of the brightly rimmed craters are too small to be resolved here, although one about 30 km (20 mi) in diameter can be easily distinguished near the center. These bright-rim craters, though the youngest features on Ariel, probably have formed over a long span of geological time. Although Ariel has a diameter of only about 1,200 km (750 mi), it has clearly experienced a great deal of geological activity in the past. The Voyager project is managed for NASA by the Jet Propulsion Laboratory.

Voir l'image PIA00041: Ariel - Highest Resolution Color Picture sur le site de la NASA.

PIA01534: Ariel's Densely Pitted Surface

This mosaic of the four highest-resolution images of Ariel represents the most detailed Voyager 2 picture of this satellite of Uranus. The images were taken through the clear filter of Voyager's narrow-angle camera on Jan. 24, 1986, at a distance of about 130,000 kilometers (80,000 miles). Ariel is about 1,200 km (750 mi) in diameter; the resolution here is 2.4 km (1.5 mi). Much of Ariel's surface is densely pitted with craters 5 to 10 km (3 to 6 mi) across. These craters are close to the threshold of detection in this picture. Numerous valleys and fault scarps crisscross the highly pitted terrain. Voyager scientists believe the valleys have formed over down-dropped fault blocks (graben); apparently, extensive faulting has occurred as a result of expansion and stretching of Ariel's crust. The largest fault valleys, near the terminator at right, as well as a smooth region near the center of this image, have been partly filled with deposits that are younger and less heavily cratered than the pitted terrain. Narrow, somewhat sinuous scarps and valleys have been formed, in turn, in these young deposits. It is not yet clear whether these sinuous features have been formed by faulting or by the flow of fluids.

JPL manages the Voyager project for NASA's Office of Space Science.

Voir l'image PIA01534: Ariel's Densely Pitted Surface sur le site de la NASA.