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Birthday · December 18, 2000

Oceans Under Jupiter's Moon Ganymede?

December 18, 2000

Every birthday is a reminder that you are made of the same material as the stars overhead — carbon, nitrogen, oxygen, all cooked in stellar...

Oceans Under Jupiter's Moon Ganymede?

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APOD published December 18, 2000. Full image credits are on the original APOD entry below. A publication-date match, not a photo taken on your date. Independent of NASA.

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Oceans Under Jupiter's Moon Ganymede?

Original APOD · December 18, 2000

The search for extraterrestrial life came back into our own Solar System last week with the announcement that there may be liquid oceans under the surface of Jupiter's moon Ganymede. Ganymede now joins Callisto and Europa as moons of Jupiter that may harbor seas of liquid water under layers of surface ice. The ocean hypothesis surfaced as an explanation for Ganymede's unusually strong magnetic field. Ganymede, the largest moon in the Solar System, also has the largest measured magnetic field of any moon. Some exobiologists hypothesize that life may be able to emerge in such an ocean, much as it did in the oceans of ancient Earth. Above, a frame from a computer simulation shows what it would look like to fly over the surface of Ganymede, as extrapolated from photographs of the grooved moon taken by the robot spacecraft Galileo currently orbiting Jupiter.

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