Based on a study entitled, “The Search for a Subsurface Ocean in Ganymede with Hubble Space Telescope Observations of its Auroral Ovals” publish by the Journal of Geophysical Research: Space Physics, NASA is reporting that Ganymede – one of Jupiter’s moons and the largest in the solar system – may have a subterranean ocean of saltwater containing more water than the surface water found on Earth.
Ganymede is larger than both Mercury and Pluto, and is close to the size of Mars by three-quarters. It was first observed by Galileo Galilei on January 7 in 1610 and was named after the mythology of a young boy who was taken to Olympus by the god Jupiter while under the form of an eagle. This young boy which was said to be extremely beautiful would become a servant to the gods on Olympus.
The satellite has three layers with a metallic iron at the core which generates a magnetic field similar to that on Earth. Around the core is a mantel and a shell of rock mostly comprised of ice. Back in 1996, it was discovered by the Hubble Telescope that a thin layered atmosphere composed of oxygen existed on the moon.
However, this oxygen is not enough to support life as it exists here on Earth. This does not mean life may have not evolved in a manner that matched the conditions found on the moon. There may be life; microbes or more complex lifeforms which developed based on the conditions available. Rock masses were discovered in 2004 under the icy terrain of Ganymede. The existence of these rock formations indicate the strength of the ice as it holds the rocks near the surface of the satellite and does not allow them to sink into the ocean believed to exist under the ice.
What is interesting is that Ganymede’s magnetic field is intertwined with that of Jupiter’s. This causes a peculiar motion of the aurorae generated by both bodies which seems to sway. Since salt is conductive, then another magnetic field would be visible over the area containing it as an interaction of forces takes place. This is what was discovered by the University of Cologne, Germany. The magnetic field on Jupiter creates another field on Ganymede showing the presence of saltwater since the fields are interacting with the salt. This is described as “magnetic friction.” The existence of this would hold back the swaying or rocking of the aurorae of both the moon and Jupiter. It is estimated that this saltwater ocean is about 65 miles across and about 10 times as deep as the oceans found on Earth and is encrusted under 95 miles of ice.