Science

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

Eric Mack has been a CNET contributor since 2011. Eric and his family live 100% energy and water independent on his off-grid compound in the New Mexico desert. Eric uses his passion for writing about energy, renewables, science and climate to bring educational content to life on topics around the solar panel and deregulated energy industries. Eric helps consumers by demystifying solar, battery, renewable energy, energy choice concepts, and also reviews solar installers. Previously, Eric covered space, science, climate change and all things futuristic. His encrypted email for tips is ericcmack@protonmail.com.

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Eric Mack

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

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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.

2 of 7 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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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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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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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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Ganymede's geology

A geologic map of Ganymede released last year.

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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.