This image by NASA’s Cassini spacecraft shows the extraordinary tectonic deformation in the fractured south polar region of Saturn’s moon Enceladus, where jets of water ice spray outward to form Saturn’s E ring. Dramatic plumes, both large and small, spray water ice out from many locations along the famed “tiger stripes” near the south pole. The tiger stripes are fissures that spray icy particles, water vapor and organic compounds. More than 30 individual jets of different sizes can be seen in the image below and more than 20 of them had not been identified before. At least one jet spouting prominently in previous images now appears less powerful. This mosaic was created from two high-resolution images that were captured by the narrow-angle camera when NASA’s Cassini spacecraft flew past Enceladus and through the jets on Nov. 21, 2009.  The south pole of the moon lies near the limb in the top left quadrant of the mosaic, near the large jet that is second from left. Lit terrain seen here is on the leading hemisphere of Enceladus (504 kilometers, 313 miles across). Cassini scientists continue to study the question of whether reservoirs of liquid water exist beneath the surface of the moon. The view was obtained at a distance of approximately 14,000 kilometers (9,000 miles) from Enceladus and at a sun-Enceladus-spacecraft, or phase, angle of 145 degrees. Image scale is 81 meters (267 feet) per pixel. This image and others like it from the close flyby of Enceladus on Nov. 21, 2009, are among the best visible light images Cassini will capture of the region around the “tiger stripes,” the fissures that spray icy particles, water vapor and organic compounds, before the moon’s south polar region enters winter darkness for the coming years. Cassini scientists will use these new images to study geological activity associated with the tiger stripes and their effects on the surrounding terrain. In this unique mosaic image combining high-resolution data from the imaging science subsystem and composite infrared spectrometer aboard NASA’s Cassini spacecraft, pockets of heat appear along one of the mysterious fractures in the south polar region of Saturn’s moon Enceladus. The fracture, named Baghdad Sulcus, is one of the so-called “tiger stripe” features that erupt with jets of water vapor and ice particles. It runs diagonally across the image. This mosaic, obtained on Nov. 21, 2009, shows a 40-kilometer (25-mile) segment of Baghdad Sulcus and illustrates the correlation between the geologically youthful surface fractures and anomalously warm temperatures recorded in the south polar region. It shows the highest-resolution data yet of the heat leaking from the moon’s interior along the tiger stripes. The anaglyph below made from images captured by NASA’s Cassini spacecraft shows a dramatic, 3-D view of one of the deep fractures nicknamed “tiger stripes” on Saturn’s moon Enceladus. The fractures, which are located near the moon’s south pole, spray jets of water ice.  Just below center in this image is an approximately 16-kilometer-long (10-mile-long) portion of the tiger stripe named Baghdad Sulcus. The Baghdad fracture is the longest of the four tiger stripes on Enceladus, with a length of 175 kilometers (108 miles). This image and others like it from the close flyby of Enceladus on Nov. 21, 2009, are among the best visible light images Cassini will capture of the tiger stripes before the moon’s south polar region enters winter darkness for the coming years. Cassini scientists will use these new images to study geological activity associated with the tiger stripes and their effects on the surrounding terrain. This information, coupled with observations by Cassini’s other instruments, will address the question of whether reservoirs of liquid water exist beneath the surface of the moon.  Detecting salty ice and negatively charged water ions in the ice plume of Enceladus hints that it could harbor a reservoir of liquid water — perhaps an ocean — beneath its surface. And, where’s there’s an ocean of liquid water, there’s a higher probability of finding some form of life. “The original picture of the plumes as violently erupting Yellowstone-like geysers is changing,” said Frank Postberg, Cassini scientist for the cosmic dust analyzer at the Max Planck Institute for Nuclear Physics in Heidelberg, Germany. “They seem more like steady jets of vapor and ice fed by a large water reservoir. However, we cannot decide yet if the water is currently ‘trapped’ within huge pockets in Enceladus’ thick ice crust or still connected to a large ocean in contact with the rocky core.” Scientists working on the Cassini space mission have found negatively charged water ions in the ice plume. Their findings, based on analysis from data taken in plume fly-throughs in 2008 provide evidence for the presence of liquid water. The Cassini plasma spectrometer, used to gather this data, also found other species of negatively charged ions including hydrocarbons. “While it’s no surprise that there is water there, these short-lived ions are extra evidence for sub-surface water and where there’s water, carbon and energy, some of the major ingredients for life are present,” said lead author Andrew Coates from University College London’s Mullard Space Science Laboratory. “The surprise for us was to look at the mass of these ions. There were several peaks in the spectrum, and when we analysed them we saw the effect of water molecules clustering together one after the other.” The measurements were made as Cassini plunged through Enceladus’ plume on March 12, 2008. Enceladus thus joins Earth, Titan and comets where negatively charged ions are known to exist in the solar system. Negative oxygen ions were discovered in Earth’s ionosphere at the dawn of the space age. At Earth’s surface, negative water ions are present where liquid water is in motion, such as waterfalls or crashing ocean waves. The Cassini plasma spectrometer, originally designed to take data in Saturn’s magnetic environment, measures the density, flow velocity and temperature of ions and electrons that enter the instrument. But since the discovery of Enceladus’ water ice plume, the instrument has also successfully captured and analysed samples of material in the jets. Early in its mission, Cassini discovered the plume that fountains water vapour and ice particles above Enceladus. Since then, scientists have found that these water products dominate Saturn’s magnetic environment and create Saturn’s huge E-ring. Casey Kazan via NASA/JPL

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Saturn’s Moon Enceladus: Do Huge Reservoirs of Water (and Life) Exist Beneath Its Surface?