A Weird Powder Puzzle on the Martian Moon Phobos May Be Solved

The Stickney Crater on Mars‘ moon Phobos. New research suggests that reddish and bluish areas on the moon’s surface point the way to understanding its formation.
(Image: © NASA/JPL-Caltech/University of Arizona)
Understanding the process could help reveal the moon’s strange origins.

By Charles Q. Choi | SPACE.com

The eccentric orbit of the Martian moon Phobos could drive the flow of powder across the moon’s surface, a new study finds, shedding light on Phobos‘ mysterious origins.

Dark gray, potato-shaped Phobos is only about 14 miles (22.5 kilometers) wide, but it is by far the larger of Mars‘ two moons, at more than seven times the mass of its companion, Deimos. Phobos orbits at only about 3,700 miles (6,000 km) from the Martian ground, closer to its planet than any known moon; as a result of this tight orbit, Phobos zips around Mars three times per Earth day.

Previous work revealed an odd dichotomy on the surface of Phobos. Some areas are reddish, while others are bluish, Ron Ballouz, lead author of the new study and an astrophysicist at the Japanese Aerospace Exploration Agency (JAXA), told Space.com.

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