Monday, January 14, 2013
APOTD: Tectonics on Enceladus
On Oct. 5, 2008, just after coming within 25 kilometers (15.6 miles) 
of the surface of Enceladus, NASA's Cassini captured this stunning 
mosaic as the spacecraft sped away from this geologically active moon of
 Saturn.
Craters and cratered terrains are rare in this view of the southern 
region of the moon's Saturn-facing hemisphere. Instead, the surface is 
replete with fractures, folds, and ridges—all hallmarks of remarkable 
tectonic activity for a relatively small world. In this enhanced-color 
view, regions that appear blue-green are thought to be coated with 
larger grains than those that appear white or gray.
Portions of the tiger stripe fractures, or sulci, are visible along the 
terminator at lower right, surrounded by a circumpolar belt of 
mountains. The icy moon's famed jets emanate from at least eight 
distinct source regions, which lie on or near the tiger stripes. 
However, in this view, the most prominent feature is Labtayt Sulci, the 
approximately one-kilometer (0.6 miles) deep northward-trending chasm 
located just above the center of the mosaic.
Near the top, the conspicuous ridges are Ebony and Cufa Dorsae. This 
false-color mosaic was created from 28 images obtained at seven 
footprints, or pointing positions, by Cassini's narrow-angle camera. At 
each footprint, four images using filters sensitive to ultraviolet, 
visible and infrared light (spanning wavelengths from 338 to 930 
nanometers) were combined to create the individual frames. The mosaic is
 an orthographic projection centered at 64.49 degrees south latitude, 
283.87 west longitude, and it has an image scale of 196 kilometers 
(122.5 miles) per pixel. The original images ranged in resolution from 
180 meters (594 feet) to 288 meters (950 feet) per pixel and were 
acquired at distances ranging from 30,000 to 48,000 kilometers (18,750 
to 30,000 miles) as the spacecraft receded from Enceladus. The view was 
acquired at a Sun-Enceladus-spacecraft, or phase, angle of 73 degrees.
Image: NASA/JPL/Space Science Institute [high-resolution]
Caption: NASA
Subscribe to:
Post Comments (Atom)
 

 
 

No comments:
Post a Comment