Saturn is best known for its beautiful system of rings. The ring system is only about 10 kilometres thick and is made up of particles of ice and dust. Most of the rings are less than one metre across, but a few are as large as 100 kilometres across. During 1995, Saturn’s rings were visible almost edge-on, making them appear to vanish as viewed from Earth.

The basics

Order (outwards from the Sun): 6
Average distance from the Sun: 1 429 000 000 km (9.56 astronomical units)
Period of revolution (length of year): 29.42 years
Period of rotation (length of day): 10 hours 40 minutes at the equator
Diameter: 120 540 km at the equator; rings are 275 000 km across
Surface gravity: 1.08 times greater than Earth’s
Composition: Scientists are not sure if Saturn is made completely of gases or if it has a solid rocky core. The entire planet has a density less than water- if you could put it in a big enough bathtub, it would float
Atmosphere: Hydrogen, helium, some methane and ammonia
Satellites: 31 moons and a ring system of 23 major rings
Surface temperature: -190 degrees Celsius at the cloud tops. Like Jupiter, Saturn radiates more heat than it receives from the Sun

Appearance of surface

Saturn has cloud structures similar to Jupiter, but not as pronounced. There is probably a liquid hydrogen ocean under the visible cloud tops.

Appearance in Earth’s sky

Saturn can be seen in the sky as a bright star-like object. It moves very slowly against the background stars, and several weeks may be required to see it change its position relative to the stars.

Telescopic appearance

A good pair of binoculars will reveal that Saturn is not quite round,due to its ring system. Almost any telescope that magnifies over 30 times will show the rings of Saturn and perhaps a faint cloud band or two on the disk of the planet.

The view of Saturn through a telescope is one of the most beautiful sights in astronomy.

Canadian Heritage Information Network
Australian Museums & Galleries Online, Australia; Centre of the Universe; Gemini Observatory, Hawaii; Glenbow Museum; The Manitoba Museum; National Research Council Canada; Planétarium de Montréal

© Canadian Heritage Information Network, 2003

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