Enceladus

Enceladus was discovered on August 28, 1789, by William Herschel. Little was known about it until the two Voyager spacecraft, Voyager 1 and Voyager 2, passed nearby in 1980 and 1981. In 2005, the Cassini spacecraft started multiple close flybys of Enceladu. In particular, Cassini discovered water-rich plumes venting from the south polar region.

About Enceladus in brief

Summary EnceladusEnceladus was discovered on August 28, 1789, by William Herschel. Little was known about it until the two Voyager spacecraft, Voyager 1 and Voyager 2, passed nearby in 1980 and 1981. In 2005, the Cassini spacecraft started multiple close flybys of Enceladu. In particular, Cassini discovered water-rich plumes venting from the south polar region. In 2014, NASA reported that Cassini found evidence for a large south polar subsurface ocean of liquid water with a thickness of around 10 km. Its resonance with Dione excites its orbital eccentricity, which is damped by tidal forces, tidally heating its interior and driving the geological activity. It orbits at 238,000km from Saturn’s center and 180,000 km from its cloud tops, between the orbits of Mimas and Tethys. It is currently in a 2: 1 mean-motion resonance with Saturn’s Dione, completing one orbit for every one orbit completed by Dione. This maintains Enceus’s orbital resonance for every 32 hours, fast enough for its motion to be observed over a single night of observation. The IAU has officially named 85 features on the moon, including impact craters and places from Burton’s translation of The Book of One Thousand and One Nights. The name, like the names of each of the first seven satellites of Saturn to be discovered, was suggested by William. Herschel’s son John Herschel in his 1847 publication Results of Astronomical Observations made at the Cape of Good Hope.

He chose these names because Saturn, known in Greek mythology as Cronus, was the leader of the Titans. The most recently named feature is Samaria Fossa, formerly called Rupes Samaria, formerly named after Samus Samaria. Enceadus is one of the major satellites of the major inner planets of Saturn along with Mimas, Tethyas, and Mimas as well as Dione and Dione’s satellite, Dione-Saturn. It was first observed during a Saturnian equinox, when Earth is within the ring plane. At such times, the reduction in glare from the rings makes the moons easier to observe. The faint apparent magnitude and its proximity to the much brighter Saturn and Saturn’s rings make Ence Ladus difficult to observe from Earth with smaller telescopes. Its surface temperature at noon only reaches −198 °C, far colder than a light-absorbing body would be. Despite its small size, Ence Gladus has a wide range of surface features, ranging from old, heavily cratered regions to young, tectonically deformed terrains. The moon is mostly covered by fresh, clean ice, making it one of the most reflective bodies of the Solar System. Over 100 geyser-like jets of water vapor, molecular hydrogen, other volatiles, and solid material, including sodium chloride crystals and ice particles, totaling about 200 kg per second.