Jupiter's Moon Ganymede May Have Layers of Oceans and Ice Like a Dagwood Sandwich

Posted on May 2, 2014

Ocean and ice layers on Ganymede

NASA researchers say Jupiter's moon Ganymede may harbor layers of oceans and ice stacked up like layers in a club sandwich. Ganymede is the largest moon in the solar system. Scientists say the findings support the idea that primitive life might have possibly arisen on the icy moon. Previously, Ganymede's rocky sea bottom was thought to be coated with ice and not liquid. Scientists say the "club sandwich" could have salty water as the bottom layer on the moon's rocky core.

Steve Vance of NASA's Jet Propulsion Laboratory in Pasadena, Calif., says in the announcement, "Ganymede's ocean might be organized like a Dagwood sandwich. This is good news for Ganymede. Its ocean is huge, with enormous pressures, so it was thought that dense ice had to form at the bottom of the ocean. When we added salts to our models, we came up with liquids dense enough to sink to the sea floor."

The researchers used computers to model the high pressure processes that form ice in deep oceans like Ganymede's. The team came up with an ocean sandwiched between up to three ice layers, in addition to the rocky seafloor. The lightest ice is on top, and the saltiest liquid is heavy enough to sink to the bottom. The results also demonstrate a possible bizarre phenomenon that causes the oceans to "snow upwards."

"As the oceans churn and cold plumes snake around, ice in the uppermost ocean layer, called 'Ice III,' could form in the seawater. When ice forms, salts precipitate out. The heavier salts would thus fall downward, and the lighter ice, or 'snow,' would float upward. This 'snow' melts again before reaching the top of the ocean, possibly leaving slush in the middle of the moon sandwich."

Take a look:

Photo: NASA/JPL-Caltech

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