09 August 2010
Saturn and two of its icy bizarre moons
Credit: NASA/JPL/Space Science Institute
NASA recently published a wonderful image of Saturn, acquired by the Saturn-orbiting Cassini spacecraft. Cassini was looking toward Saturn's southern hemisphere, from below the plane of the planet’s magnificent rings, which lie in Saturn’s equatorial plane. Two of the planet's icy intriguing moons have been recorded in the image. The two moons are, in order of size, Rhea (1,528 km across) and Tethys (1,062 km across).
Rhea and Tethys orbit their giant planet in the plane of its rings, but from the viewpoint of Cassini, they were below the planet, when the picture was taken. Tethys is near the center of the image, and Rhea, Saturn’s second largest moon, is at lower right.
This view looks toward the southern, dark side of the rings, from about 12 degrees below the ringplane. It was acquired with Cassini’s wide-angle camera, on 29 June 2010, in an infrared filter. The spacecraft was at a distance of approximately 2.1 million km from Saturn.
Cassini was launched toward Saturn in October 1997. It has voyaged in interplanetary space for about seven years, to reach Saturn. It entered orbit around Saturn on 1 July 2004. Cassini has orbited Saturn more than 125 times, and acquired more than 210,000 images of the planet and its moons. It is expected that Cassini’s mission will continue till 2017.
Further Reading
Cassini Mission Homepage
http://saturn.jpl.nasa.gov/
Aymen Mohamed Ibrahem
Senior Astronomy Specialist