A fracture history on Enceladus provides evidence for a global ocean

The region surrounding the south pole of Saturn's moon Enceladus shows a young, pervasively fractured surface that emanates enough heat to be detected by the Cassini spacecraft. To explain the elevated heat and eruptive icy plumes originating from large cracks (informally called “tiger stripes”) in the surface, many models implicitly assume a global liquid ocean beneath the surface. Here we show that the fracture patterns in the south-polar terrain (SPT) of Enceladus are inconsistent with contemporary stress fields, but instead formed in a temporally varying global stress field related to nonsynchronous rotation of a floating ice shell above a global liquid ocean. This finding increase to at least three the number of outer planet satellites likely to possess a subsurface liquid water layer.