[69][70][71] This is consistent with geophysical calculations which predict the south polar fissures are under compression near periapsis, pushing them shut, and under tension near apoapsis, pulling them open. Cassini will be a continuing help in providing such information. It is an extremely wide but diffuse disk of microscopic icy or dusty material distributed between the orbits of Mimas and Titan. i The results of the new study offer clues to how life started on Earth and where else in the cosmos we might find it. Shares. Credits: NASA/JPL-Caltech. For a same-temperature approximation, the expected value of qtid for Mimas is about 40 times that of Enceladus. A mass spectrometer on the craft detected molecular hydrogen (H2) from the plume, and after months of analysis, the conclusion was made that the hydrogen was most likely the result of hydrothermal activity beneath the surface. From deep below the soil at Earth’s polar regions to Pluto’s frozen heart, ice exists all over the solar system...and beyond. [6] However, the current shape also supports the possibility that Enceladus is not in hydrostatic equilibrium, and may have rotated faster at some point in the recent past (with a differentiated interior). With its global ocean, unique chemistry and internal heat, Enceladus has become a promising lead in our search for worlds where life could exist. Saturn's ocean moon Enceladus has fresh ice in unexpected place. The presence of an internal global salty ocean with an aquatic environment supported by global ocean circulation patterns,[144] with an energy source and complex organic compounds[30] in contact with Enceladus's rocky core,[27][28][147] may advance the study of astrobiology and the study of potentially habitable environments for microbial extraterrestrial life. [134], The significantly higher density of Enceladus relative to Mimas (1.61 vs. 1.15 g/cm3), implying a larger content of rock and more radiogenic heating in its early history, has also been cited as an important factor in resolving the Mimas paradox. The measurements suggested a large sea about 6 miles (10 kilometers) deep beneath the southern polar region, under an ice shell about 19 to 25 miles (30 to 40 kilometers) thick. Optical illusions from a combination of viewing direction and local fracture geometry previously made the plumes look like discrete jets. JPL has won an Emmy Award for Outstanding Original Interactive Program for its coverage of the Cassini mission's Grand Finale at Saturn. [119][129], Enceladus is a relatively small satellite composed of ice and rock. The smooth plains, which Voyager 2 had observed, resolved into relatively crater-free regions filled with numerous small ridges and scarps. [104], A model suggests that Enceladus's salty ocean (-Na, -Cl, -CO3) has an alkaline pH of 11 to 12. [68] The intensity of the eruption of the south polar jets varies significantly as a function of the position of Enceladus in its orbit. (Image credit: NASA/JPL-Caltech/University of Arizona/LPG/CNRS/University of Nantes/Space Science Institute). [126], The "hot start" model of heating suggests Enceladus began as ice and rock that contained rapidly decaying short-lived radioactive isotopes of aluminium, iron and manganese. It includes activities that can be done at home as well as videos, animations, stories, and articles. In 2015, the Cassini probe made a close fly-by of Enceladus's south pole, flying within 48.3 km (30 mi) of the surface, as well as through a plume in the process. Cassini also found the first signs of hydrothermal activity beyond Earth – making this tiny Saturnian moon one of the leading locations in the search for possible life beyond Earth. Distance from Sun: 9.5 Astronomical Units (AU) (Earth = 1 AU). [108][109], During the flyby of July 14, 2005, the Composite Infrared Spectrometer (CIRS) found a warm region near the south pole.