Hidden Ocean Discovered on Saturn’s Moon Enceladus

By Bill Andrews | April 3, 2014 1:00 pm
enceladusstripes_cassini

Credit: Cassini Imaging Team, SSI, JPL, ESA, NASA

If you know anything about Enceladus, an icy moon in Saturn’s tow, it’s probably the amazing jets of water spurting off the satellite’s south pole. The image is one of the most stunning to come from NASA’s Cassini spacecraft, orbiting within the Saturnian system for 10 years — not just because it looks cool, but because it showed that tiny Enceladus, just over 300 miles across, could harbor interesting activity.

Well that was just the start: new findings from Cassini indicate that Enceladus hosts a huge subsurface sea of liquid water beneath its south pole, possibly fueling those very jets.

Entering Enceladus

The Cassini probe is pretty impressive. Not only does it have your standard space cameras to capture pretty pictures and important information, but the probe itself can measure a world’s mass distribution. The subtle variations of mass pull on Cassini with slightly different gravitational strengths, so scientists can learn about a body’s internal structure just by seeing what the probe does.

Enceladus diagram

Scientists have found evidence of a large ocean of liquid water on Enceladus, squeezed between a rocky core and a thick sheet of ice. Credit: NASA/JPL-Caltech

After three close flybys of Enceladus (within 62 miles, or 100 km), Cassini revealed something odd about the moon’s south pole: It didn’t have enough stuff on the surface to account for the strong gravitational tug it exerted on the probe. Something else, almost certainly a subterranean ocean of liquid water, was accounting for that strong gravity. More specifically, the water is likely 18 to 24 miles down, trapped between a rocky core and an outer shell of ice. The findings appear in this week’s edition of Science.

Tip of the Ice Sheet

Only a handful of worlds (including our own) are known to have liquid water in any abundance, so the news is exciting purely on its own merits. But it’s also great to finally have a possible answer to what was fueling those impressive jets of water.

Spewing out of long, unusual fractures on the surface nicknamed “tiger stripes,” the jets had led astronomers to suspect a possible subsurface reservoir, but with no evidence to prove it. With this data, not only do astronomers finally have evidence as to what might be feeding the jets, but they even know how widespread the water is — extending up to latitudes of nearly 50° in the southern hemisphere, making the ocean about the same size as Lake Superior.

Which isn’t to say it’s all figured out, of course. Scientists suspect the tiger strips, jets and subsurface ocean might ultimately be the result of heating deep within the moon, as its core stretches and flexes during its approaches to Saturn.

Exactly what’s going on, however — along with the nature of Enceladus’ water and whether it might be part of a habitable environment — will require even more data. Let’s hope Cassini doesn’t wait another 10 years before answering some of those questions.

 

CATEGORIZED UNDER: Space & Physics, top posts
MORE ABOUT: Enceladus, solar system
  • Adam Crowl

    Would imply something similar about Europa’s ocean too.

    • John S.

      With life as it is in our own parts of the ocean that are lightless and freezing, it’s very likely that both this and Europa could have living organisms. We won’t know till we go there and drill. Space squids, though. Space squids.

      • CJ

        :O

        • Cristina Samsa

          :p

  • http://sciencedem.blogspot.com editor

    Oceans typically have Life.

    • Stephen Frey

      Given the liquid water has been there for a very long period,life of some sort probably exists there.

    • Tom

      You mean Earth oceans. No one knows what the oceans of other planets may contain.

  • Rick Bowman

    Is there evidence the ice is h2o? I thought it was ammonia.

    • Jessica Milek

      “almost certainly a subterranean ocean of liquid water”

      • http://blogs.discovermagazine.com Richard Hayward

        Europa’s ocean is salt water.

        • Tom

          Sure it is…and it may contain shrimp, scallops, oysters, and other similar ocean life forms just as in Earth’s “salt water” oceans.

      • SILENTHAMMER

        At those temps, what’s keeping it from freezing, and what’s making it “jet”?

    • Emkay

      I thought it was methane….

      • Guy smiley

        Titan is methane

  • wendyo123

    My Uncle James recently got a new black Mazda
    MAZDASPEED3 Hatchback by working at home online. you can try here B­i­g­4­1­.­ℂ­o­m

  • Wullum

    I simply could not be more excited…This is beyond amazing!

    • Emkay

      easy now….

      • Wullum

        I know, but this opens the imagination to exciting new challenges that transcend lunar or Martian trips. I would love to see a rover land on Enceladus and send us some (more) awesome photographs!

        • Tom

          This will not happen for at least another 100 years…at most.

  • Tom

    It would be easy to find out if the water contains life forms. Simply make a Cassini flyby over the water jets and scoop up water samples from the jets.

    • Wullum

      Easy?

      • Tom

        Cassini is more sophisticated than you can imagine. Yes…easy.

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