Jupiter's Ganymede moon hides a big ocean (pictures)

Observations from the Hubble Space Telescope have confirmed that there's a salty subsurface ocean on Jupiter's largest moon.

Eric Mack

March 12, 2015 9:47 a.m. PT

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NASA/ESA

Ganymede's hidden ocean

Ganymede, Jupiter's largest moon, has long been suspected of harboring a subsurface ocean. Now, using the Hubble telescope to spy on its aurorae, scientists say they can confirm a salty ocean beneath its frozen crust.

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NASA/ESA/G.Bacon (STSci)

Ganymede's aurorae

Ganymede is the rare moon that generates its own magnetic field, creating observable aurorae that scientists used to infer the presence of a subsurface ocean.

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NASA/ESA

Jovian lights

Ganymede's Aurora, as spied by Hubble. Because the moon is also embedded in Jupiter's magnetic field, the friction causes the lights to "rock back and forth."

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NASA/ESA

An attractive moon

Ganymede is the only moon in the solar system to create its own magnetosphere, thanks to its liquid iron core.

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NASA/ESA

The moon is a rockin' (but not much)

Scientists found that the aurorae on Ganymede did not "rock" as much as expected, leading to the conclusion that a subsurface ocean was present and inhibiting the effect.

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NASA

Ganymede's geology

A geologic map of Ganymede released last year.

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NASA

Profile

Ganymede as observed from the Galileo spacecraft. The confirmed presence of a salty ocean on the moon will make it an instant source of increased interest for space geeks.