14 September 2010
Credit: NASA/JPL/Space Science Institute
NASA recently published a wonderful image of Enceladus, Saturn’s icy, geologically-active moon. The image was acquired from orbit around Saturn, by the Cassini spacecraft. It shows spectacular water ice plumes, emanating from the south polar region of Enceladus (504 km across). These plumes are an amazing type of volcanic activity, termed cryovolcanism.
Cryovolcanoes erupt cold material, rather than molten glowing rocks. The plumes of Enceladus resemble terrestrial geysers. They were discovered by Cassini, in 2005.
This image was captured at an angle of 159 degrees, so that sunlight would reveal the backlit plumes. Please visit the following link, for more information.
http://photojournal.jpl.nasa.gov/catalog/PIA11688
Sunlight reflected off Saturn faintly illuminates the night side of Enceladus, which was in the crescent phase. The light of this crescent is reflected sunlight. Stars are visible in the background as pale, short streaks of light, due to the motion of the spacecraft.
The image was taken in visual light, with Cassini’s narrow-angle camera, on 13 October 2009. The view was obtained at a distance of approximately 431,000 km from Enceladus.
References
Photojournal article
http://photojournal.jpl.nasa.gov/catalog/PIA12713
NASA
www.nasa.gov/
Wikipedia
Aymen Mohamed Ibrahem
Senior Astronomy Specialist