“The release of heat in narrow regions favors intense interaction between water and rock, and the transport of hydrothermal products from the core to the [water] plume sources,” the authors write. “We are thus able to explain the main global characteristics of Enceladus: global ocean, strong dissipation, reduced ice-shell thickness at the south pole, and seafloor activity.”
The authors say that Enceladus’s core is likely a metal-rock nucleus with a lot of water-filled areas, as well as many iron-bearing hydrated materials; the abundance of these materials, they added, would hint as to how much water is in the core. The models included information from parameters such as the libration (oscillation or wobbling) of Enceladus that was detected by Cassini, observed sediments flowing underneath glaciers, and loading tests on granular materials.
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These findings have implications for potential life on Enceladus. Cassini’s detection of hydrogen gas in one of the moon’s plumes fueled the idea that hydrothermal vents lie deep inside the moon’s subsurface ocean. They might possibly resemble those that are found on Earth, where chemical reactions could theoretically have produced the beginnings of microbial life on our planet. If so, then similar hydrothermal activity taking place on Enceladus for billions of years may have given potential life an opportunity to evolve on the icy moon.
While the authors acknowledge this possibility, a dedicated mission to Enceladus would be required to learn more. NASA has no immediate plans to return to the moon, although a mission called the Enceladus Life Finder was submitted to a call for proposals for NASA's next “New Frontiers” medium-class mission earlier this year.
Other examples of New Frontiers missions include New Horizons, which flew by Pluto in 2015, and Juno, which is currently orbiting Jupiter.
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