15 August 2010
Credit: NASA/JPL/Space Science Institute
NASA recently published a wonderful image of Enceladus, an icy, geologically-active moon of Saturn. The image was acquired by the Saturn-bound Cassini spacecraft, from orbit around the ringed giant planet.
Cassini’s image records a plume of water ice, emanating from the south polar region of Enceladus (504 km across). Interestingly, this is a type of volcanism, known as cryovolcanoes, or ice volcanoes.
Enceladus’ plume originates from linear fractures on Enceladus, known as the tiger stripes, and it extends for hundreds of kilometers into space. Enceladus’ volcanic activity was first observed by Cassini, in 2005. It is believed to be the source of Saturn’s broad delicate E ring, the outermost of the Saturn’s magnificent rings. The outer edge of the E ring is approximately 483,000 km in radius.
The following links feature more information on Enceladus and the E ring.
http://photojournal.jpl.nasa.gov/catalog/PIA11688
http://photojournal.jpl.nasa.gov/catalog/PIA08321
The E ring is just faintly visible in this image, as a narrow pale band, stretching across the middle. The illumination of Enceladus is due to direct sunlight and sunlight reflected off Saturn.
The image was taken in visual light, with Cassini’s narrow-angle camera, on 26 April 2010. The spacecraft was approximately 993,000 km from Enceladus.
Enceladus orbits Saturn every 32.9 hours, at a distance of about 238,000 km. It was discovered in 1789, by Sir William Herschel (1738-1822), the discoverer of Uranus, the seventh planet. The moon’s name comes from Greek mythology.
Further Reading
The Cassini Mission Homepage
http://photojournal.jpl.nasa.gov/catalog/PIA08321
Aymen Mohamed Ibrahem
Senior Astronomy Specialist