25 March 2011
A Cassini spacecraft image of Helene, Saturn’s tiny, curious moon
Credit: NASA/JPL/Space Science Institute
NASA recently published an amazing image of a small icy moon of Saturn, known as Helene. The image was acquired by the Saturn-orbiting Cassini spacecraft, on 31 January 2011, when Cassini flew by Helene (33 km across), at a distance of approximately 31,000 km.
Helene is irregular in shape, resembling a huge rugged rock. Intriguingly, Helene and a dwarf moon, known as Polydeuces (3 km across), share orbit with one of Saturn’s major moons, known as Dione (1,126 km across). There is only one similar case in the Solar System, as three other Saturnian moons occupy the same orbit.
A Cassini spacecraft image of Dione.
Credit: NASA/JPL/Space Science Institute
A Cassini spacecraft image of Polydeuces.
Credit: NASA/JPL/Space Science Institute
Helene orbits Saturn every 2.73 days, at a distance of approximately 380,000 km. The names of most of the planetary moons come from ancient mythologies. In Greek mythology, Helene was the granddaughter of Cronus (Saturn), the god of agriculture, and sister of Polydeuces. Dione was the wife of Zeus (Jupiter), the king of gods, and mother of Aphrodite (Venus), the goddess of beauty.
References
NASA
www.nasa.gov/
Cassini Mission
http://saturn.jpl.nasa.gov
Photojournal
http://photojournal.jpl.nasa.gov/
Wikipedia
The Eight Planets Website
Aymen Mohamed Ibrahem
Senior Astronomy Specialist