Researchers at NASA have confirmed the existence of a subsurface global ocean on Saturn’s moon Enceladus.
This conclusion was reached by analyzing a small but noticeable wobble of the moon as it orbits the gas giant. Its motion is large enough it could only be the result of a massive shell of ice resting on top of water, and would not occur in the same manner if the ice was frozen solid down to the moon’s core. If that were the case, Enceladus would be carrying around a much greater “dead weight” and not wobble nearly as much.
Enceladus is well-known for a series of icy geysers located at its south pole. The geysers are fed by the liquid water ocean beneath, although it is not known what keeps the water in liquid form so far from the sun. One intriguing possibility is that tidal gravity is massaging the moon’s core, similarly to how Jupiter’s gravity produces great volcanoes of sulfur on its moon, Io.
The data that allowed scientists to reach this conclusion was gathered by the Cassini probe. Launched in 1997, it has been orbiting Saturn since 2004. -MAX