Wikipedia
Enceladus is a moon of Saturn.
Enceladus may also refer to:
- Enceladus (mythology), a mythological giant
- USS Enceladus (AK-80), an American cargo ship
Enceladus (pronounced ) is the sixth-largest moon of Saturn. It is approximately in diameter, about a tenth of that of Saturn's largest moon, Titan. Enceladus is mostly covered by fresh, clean ice, reflecting almost all the sunlight that strikes it, making its surface temperature at noon reach only . Despite its small size, Enceladus has a wide range of surface features, ranging from old, heavily cratered regions to young, tectonically deformed terrains that formed as recently as 100 million years ago.
Enceladus was discovered in 1789 by William Herschel, but little was known about it until the two Voyager spacecraft passed nearby in the early 1980s. In 2005, the Cassini spacecraft started multiple close flybys of Enceladus, revealing its surface and environment in greater detail. In particular, Cassini discovered water-rich plumes venting from the south polar region. Cryovolcanoes near the south pole shoot geyser-like jets of water vapor, other volatiles, and solid material, including sodium chloride crystals and ice particles, into space, totaling approximately per second. Over 100 geysers have been identified. Some of the water vapor falls back as "snow"; the rest escapes, and supplies most of the material making up Saturn's E ring. According to NASA scientists, the plumes are similar in composition to comets. In 2014, NASA reported that Cassini found evidence for a large south polar subsurface ocean of liquid water with a thickness of around .
These geyser observations, along with the finding of escaping internal heat and very few (if any) impact craters in the south polar region, show that Enceladus is geologically active today. Like many other satellites in the extensive systems of the giant planets, Enceladus is trapped in an orbital resonance. Its resonance with Dione excites its orbital eccentricity, which is damped by tidal forces, tidally heating its interior, and possibly driving the geological activity.
In Greek mythology, Enceladus ( Enkélados) was one of the Giants, the offspring of Gaia (Earth), and Uranus (Sky). Enceladus was the traditional opponent of Athena during the Gigantomachy, the war between the Giants and the gods, and was said to be buried under Mount Etna in Sicily.