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What Makes the Rings of Saturn?

The gas giant Saturn is known for the rings that surround the planet. The rings, a majority of which is composed of billions of particles of frozen water, have prompted countless theories since their initial discovery.

Origin
- Scientists know Saturn's rings all formed differently. For example, the outer ring is made of ice from the moon Enceladus. However, it is unknown when the rings formed.
History
- Astronomer Galileo Galilei discovered Saturn's rings in 1610, thinking them a pair of additional planets following Saturn's orbit. In 1659, Christiaan Huygens identified them as rings, albeit rings that were completely solid and flat.
Naming and Order
- Saturn's rings were named in alphabetically as they were identified. From inside to outside, they are ordered D, C, B, A, F, G and E. There are several more rings made of ice, but they have not been named.
Structure
- The rings spread out for thousands of miles, but are only about 30 feet thick, according to NASA. The largest gap in the rings is called the Cassini division, discovered by Italian-born astronomer Giovanni Cassini in 1676.
Cassini Mission
- NASA launched the Cassini orbiter on Oct. 15, 1997, to study Saturn, including its rings and moons. Cassini arrived on June 30, 2004, and finished its mission in June 2008. A mission extension to 2010 allowed Cassini to observe the planet's seasons during its August 2009 equinox.

Astronomy