Saturn Facts
| Discoverer: | Unknown |
| Spacecraft Encounters: |
Pioneer 11 (1979); Voyager 1 & 2 (1980, 1981) Cassini - Huygens (2004) |
| Mean Distance from the Sun: | 9.539 AU 1, 427,000,000 km /886,700,000 mi |
| Length of Year: | 29.46 Earth years |
| Rotation Period: | 10.66 hours |
| Mean Orbital Velocity: | 9.64 km/s (6 mi/s) |
| Inclination of Axis: | 26.73 degrees |
| Diameter: | 120,536 km (74,901 mi) |
| Number of Observed Satellites: | >25 |
|
Comparisons With Earth: | |
| Diameter: | 9.4 X Earth's |
| Average Distance from the Sun: | 9.5 X Earth's |
| Mass: | 95 X Earth's |
| Density: | 0.13 X Earth's |
The Rings of Saturn
|
In 1610, Galileo observed the peculiar appearance of Saturn, but was not able to recognize the true shape of the features on either side of the planet. It was not until almost 50 years later that the astronomer Christian Huygens discovered that the shapes were really rings. |
|
| Saturn Ring Plane Crossing, 1995
|
One obstacle to the recognition of Saturn's rings was that
they are seen edge-on from Earth every 15 years, and thus seemed to
disappear.
Photo#PRC95-31 from the Space Telescope Science Institute. |
Structure In The Rings
| By 1675, Jean Dominique Cassini had discovered a gap in the rings that now bears his name (the Cassini Division). Numerous other gaps and rings were discovered by Earth-based telescopes through the 1970s, so that by the time Pioneer 11 arrived in 1979, the light and dark bands had their own set of names. | |
|
Voyager 2 Image showing Cassini Division |
Pioneer 11 close-up of Saturn's ring structure. |
| | |
