The fourth-largest satellite of Saturn, 1123 km in diameter; also known as Saturn IV. Dione orbits 377 415 km from Saturn in 2.737 days, sharing its orbit with the much smaller Helene. Its axial rotation is the same as its orbital period. Dione was discovered in 1684 by G. D. Cassini. The two hemispheres of Dione show different crater densities, the trailing face being more heavily cratered. The trailing hemisphere also displays extensive bright complexes of scarps and fissures which give an overall appearance of wispy streaks many hundreds of kilometres in length. Dione’s density is 1.5 g/cm3, suggesting that it consists of ice with a rocky core.
http://photojournal.jpl.nasa.gov/catalog/PIA08256
One of the major satellites of Saturn, with a radius of 560 km; mass 10.52 × 1020 kg; mean density 1440 kg/m3; visual albedo 0.7. It was discovered in 1684 by G. D. Cassini.
- Hundred Days Reform (1898)
- Hundred Flowers Movement (1956–57)
- Hundred Years War
- Hund’s rules
- Hungaria group
- Hungarian Revolution (23 October–4 November 1956)
- Hungary
- hunger
- Hunger Vulnerability Index
- Hungry Forties
- Huns
- Hunter process
- hunter’s Moon
- Hunt, Henry (1773–1835)
- hunting
- hunting and gathering
- Huntsman process
- Huron
- Huronian
- hurricane
- Hurricane Katrina (2005)
- Husband, Rick Douglas (1957–2003)
- hussar
- Hussein ibn Ali (1856–1931)
- Hussein ibn Talal (1935–99)