Bizarre Bulge Found on Ganymede, Solar System's Largest Moon
By Nadia Drake
Ganymedes bulge appears to be made of thick ice, suggesting that once upon a time, the moons icy shell rotated atop the rest of the moon.
Theres a big, weird bulge on Ganymede, the largest moon in the solar system. Protruding from a spot on the moons equator, the bulge is about 375 miles (600 kilometers) across, about the area of Ecuador, and two miles (three kilometers) tall, about half the height of Mount Kilimanjaro.
Its not at all what scientists expected to find on this moon of Jupiter.
I found it a bit by accident while I was looking to complete the global mapping of Ganymede, says planetary scientist Paul Schenk of the Lunar and Planetary Institute, in Houston. He reported the weird feature on March 20 at the Lunar and Planetary Science Conference.
The size and location of Ganymedes bulge, which appears to be made of thick ice, suggest that once upon a time, the moons icy shell rotated atop the rest of the moon, like an interplanetary Magic 8 Ball.
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http://news.nationalgeographic.com/2015/03/150326-jupiter-moon-ganymede-ocean-ice-science/