Jupiter's Largest Moon Could be Hiding a Secret Ocean 10 Times Deeper Than Earth's

Of course, the moon is also affected by its host planet, Jupiter, with its powerful magnetic field also having an effect on the moon's dancing lights. This interplay between two magnetic fields would cause the aurorae to rock, but careful observations by Saur and his team using the Hubble Space Telescope have revealed that this rocking is a lot more subtle than it should be.

So what's going on? The most likely explanation, according to the researchers, is that there is a stunningly large saltwater ocean just beneath the moon's surface that can counter the effects of Jupiter's field.

Saur explained in a NASA release that the sea's own "magnetic friction" could suppress Jupiter's field so strongly that it reduces the rocking of aurorae to 2 degrees, instead of the normal 6 degrees if the ocean was not present.

But this would also mean that the ocean would have to be an average of 60 miles deep - that's 10 times deeper than Earth's expansive oceans. And what's more, this ocean would have to be beneath an estimated 95 miles of ice and stone. That may mean humanity will be a long way away from checking out this subterranean ocean world for ourselves, even if plans to investigate the oceans of Europa and Enceladus with unmanned landers see fulfillment within the next few generations.

It should also be noted that this isn't the first time that experts have suggested that the massive moon plays host to an ocean, but it is the first time where strong evidence is presented in favor of the theory. Before that, astronomers simply held a suspicion, comparing the moon to other icy worlds.

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