Bizarre Bulge Found on Ganymede, Solar System's Largest Moon

Enormous bulge at the moon’s equator suggests Ganymede’s poles have shifted by 90 degrees.

There’s a big, weird bulge on Ganymede, the largest moon in the solar system. Protruding from a spot on the moon’s 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.

It’s 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 Ganymede’s bulge, which appears to be

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