News and commentary about the Great Frontiers

ISS007-E-10807 (21 July 2003) --- This view of Earth's horizon as the sunsets over the Pacific Ocean was taken by an Expedition 7 crewmember onboard the International Space Station (ISS). Anvil tops of thunderclouds are also visible. Credit: Earth Science and Remote Sensing Unit, NASA Johnson Space Center

Image Credit: ISS007-E-10807 (21 July 2003) – Earth Science and Remote Sensing Unit, NASA Johnson Space Center

Enceladus: Active Ice World?



Enceladus, a tiny moon of Saturn, may be a world of water ice volcanoes actively resurfacing the surrounding terrain, according to planetary scientists. Surprised by tantalizing evidence of activity, scientists believe Enceladus may be the primary source of material for one of Saturn’s rings.

Data from Titan has shown that water ice in the outer solar system is as hard as rock and plays a role similar to the silicates that make up the rocky bodies of the inner solar system. A gravitational tug-and-pull between Enceladus and another Saturnian moon, Mimas, may provide enough energy to partially melt portions of its inner mantle or core, providing a ready supply of material to erupt onto the surface and out into space. The possible presence of ammonia in that water may act as antifreeze to create “molten” water.

The Cassini spacecraft was commanded to fly by Enceladus on Thursday, July 14, 2005 much closer than originally planned. The flyby distance was only 172 km (107 miles) compared to 1,000 km (622 miles) to provide the highest resolution images ever of this ice world. Cassini will not fly by Enceladus again until March 12, 2008.

The Cassini mission team is currently processing the data and the first images are beginning to show up in the “Raw Images” database on the website. The image above was taken when Cassini was approximately 207,529 kilometers away from Enceladus. Scientists will look at images that include resolutions as small as 40 meters per pixel to try to determine if the moon is currently active. The surface map to the right illustrates the regions that were to be covered by Cassini’s cameras and the expected resolution. The south pole of Enceladus was to have been imaged for the first time. Check back with The Frontier Channel from time to time over the next few days for the latest news about the Enceladus flyby.

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