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Cassini at Enceladus

October 27, 2015

The Cassini spacecraft is scheduled to take a shower tomorrow. It’ll plunge through plumes of water vapor and ice that shoot into space from the south pole of Enceladus, one of the moons of Saturn.

Cassini discovered those plumes 10 years ago, not long after entering orbit around Saturn. The plumes jet into space from cracks in the moon’s icy crust. They appear to come from an ocean of liquid water that’s about 20 miles below the surface.

Cassini has flown through the plumes before. It’s found that in addition to water, they contain methane and microscopic grains of rock. That suggests that hydrothermal vents dot the ocean floor.

Such vents are found in Earth’s oceans as well. Water seeps deep into the rocks, where it’s heated by pools of magma. The hot water then shoots back up into the ocean, carrying dissolved minerals. The vents are home to an amazing array of life.

A similar process may be playing out on Enceladus. As the hot water shoots back up into the ocean, it may pass through layers of methane ice. So as the watery plumes shoot into space, they carry methane and bits of rock. The combination of water, heat, and minerals suggests that the hydrothermal vents could be a comfortable home for microscopic life.

Cassini will learn more as it flies just 30 miles from Enceladus tomorrow. Its instruments will get their best “taste” of the plumes, revealing more about a possible abode for life on one of the moons of Saturn.

Script by Damond Benningfield, Copyright 2015

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