The NASA Cassini Mission has shown that a global ocean underneath the icy crust of Saturn's moon Enceladus. The moon exhibits a slight wobble as it orbits Saturn, which researchers explained is a result of an interior that is less frozen than its icy shell.
According to a news release, the presence of an underlying global ocean also explains the fine spray of water vapor, icy particles and simple organic molecules found protruding from fractures near the moon's south pole that were noted in previous studies. The new findings were recently published in the journal Icarus.
"This was a hard problem that required years of observations, and calculations involving a diverse collection of disciplines, but we are confident we finally got it right," Peter Thomas, lead author and a Cassini imaging team member at Cornell University, Ithaca, and New York, said in the release.
In order to conclude that the underlying ocean was in fact global, the researchers analyzed Enceladus images taken over the course of seven years. From this, they were able to map features observed on the surface as well as examine the satellite's slight wobble.
"If the surface and core were rigidly connected, the core would provide so much dead weight the wobble would be far smaller than we observe it to be," Matthew Tiscareno, co-author and a Cassini participating scientist at the SETI Institute, Mountain View, California, said in a statement. "This proves that there must be a global layer of liquid separating the surface from the core."
The researchers have yet to discover what caused the liquid reservoir below Enceladus' icy crust.
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