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NASA's Cassini spacecraft has provided scientists the first clear evidence that Saturn's moon Enceladus harbors hydrothermal activity that suggests that it could support life.
Hydrothermal activity occurs when seawater infiltrates and reacts with a rocky crust and emerges as a heated, mineral-laden solution, a natural occurrence in Earth's oceans. According to two science papers, the results are the first clear indications an icy moon might have similar ongoing active processes.
The paper relates to microscopic grains of rock detected by Cassini in the Saturn system. An extensive, four-year analysis of data from the spacecraft, computer simulations and laboratory experiments led researchers to the conclusion the tiny grains most likely form when hot water containing dissolved minerals from the moon's rocky interior travels upward, coming into contact with cooler water. Temperatures required for the interactions that produce the tiny rock grains would be at least 194 degrees Fahrenheit (90 degrees Celsius).
Sean Hsu, a postdoctoral researcher at the University of Colorado at Boulder and Frank Postberg, a Cassini CDA team scientist at Heidelberg University in Germany with colleagues at the University of Tokyo who performed the detailed laboratory experiments that validated the hydrothermal activity hypothesis.
The Japanese team, led by Yasuhito Sekine, verified the conditions under which silica grains form at the same size Cassini detected. The researchers think these conditions might exist on the seafloor of Enceladus, where hot water from the interior meets the relatively cold water at the ocean bottom.
The study is published in the journal Nature.
