Saturn, the sixth planet from the Sun, is famous for its magnificent ring system. However, the planet also possesses a vast and diverse collection of natural satellites, or moons. As of today, Saturn has 146 confirmed moons, including 62 that have been officially named.
Overview of Saturn's Moons
Saturn's moons range significantly in size, composition, and orbital characteristics. They can be broadly categorized into several groups:
- Major Moons: These are the largest and most widely studied moons, with enough mass to achieve a spherical or near-spherical shape.
- Irregular Moons: These are small moons with large, eccentric, and highly inclined orbits, often grouped by their orbital characteristics (e.g., Norse, Inuit, and Gallic groups).
- Ring-Embedded and Ring-Grazing Moons: Small moons that orbit within or near Saturn's rings, such as the shepherd moons.
The Major Moons
Saturn's largest moons exhibit a wide range of unique features and are prime targets for scientific research.
|
Moon |
Discoverer |
Discovery Date |
Key Characteristics |
|---|---|---|---|
|
Titan |
Christiaan Huygens |
1655 |
Saturn's largest moon; has a dense atmosphere and liquid methane lakes. |
|
Rhea |
Giovanni Cassini |
1672 |
Second largest moon; icy with a heavily cratered surface. |
|
Iapetus |
Giovanni Cassini |
1671 |
Features a distinct two-tone coloration and an equatorial ridge. |
|
Dione |
Giovanni Cassini |
1684 |
Icy moon with bright ice cliffs and evidence of past geologic activity. |
|
Tethys |
Giovanni Cassini |
1684 |
Known for the immense canyon, Ithaca Chasma, and a large impact crater, Odysseus. |
|
Enceladus |
William Herschel |
1789 |
Exhibits active cryovolcanism (ice geysers) at its south pole, suggesting a subsurface ocean. |
|
Mimas |
William Herschel |
1789 |
Smallest of the major moons; famous for the large impact crater, Herschel, which makes it resemble the Death Star. |
Notable Small Moons
While smaller, many of Saturn's lesser moons play crucial roles in maintaining the structure of the ring system or have their own intriguing properties.
Shepherd Moons
These small moons orbit near the rings and help to maintain their sharp edges and structure through gravitational influence.
- Prometheus and Pandora shepherd the F Ring.
- Daphnis orbits within the Keeler Gap in the A Ring.
Unique Moons
Some small moons possess highly unusual characteristics.
- Phoebe: The largest of the irregular moons; orbits far from Saturn in a retrograde direction (opposite to the planet's rotation).
- Hyperion: Has a chaotic rotation and a porous, sponge-like appearance, believed to be a remnant of a larger moon destroyed by an impact.
- Janus and Epimetheus: Share almost the same orbit and periodically swap places every four years, narrowly avoiding a collision.