'Oddball' moon Hyperion
This NASA/ESA/ASI Cassini-Huygens image reveals the odd shape of Saturn's moon Hyperion and an intriguing variation in brightness across its surface.
Hyperion is one of the smaller moons of Saturn, with a diameter of 266 kilometres, but larger than Phoebe. It has a pock-marked body and is one of the largest irregularly shaped satellites ever observed.
Hyperion might have had a major collision which blew part of the moon away. Its eccentric orbit makes it subject to gravitational forces from Saturn which have set it tumbling out of control.
The largest crater on its surface is approximately 120 kilometres in diameter and 10 kilometres deep. With evidence of bombardment by meteors, and its irregular shape, Hyperion appears to be the oldest surface in the Saturnian system.
This image was taken in visible light with the Cassini-Huygens spacecraft narrow-angle camera on 20 October 2004, at a distance of about 2.2 million kilometres from Hyperion. The image scale is 13 kilometres per pixel.
The Cassini-Huygens mission is a co-operative project of NASA, ESA and ASI, the Italian space agency.
Credits: NASA/JPL/Space Science Institute