Asteroids

Asteroids
Asteroids Phobos, the larger of the two Martian moons, may be an asteroid captured by the planet's gravity. It is only about 20 kilometers in diameter and is very dark, suggesting that it ay be related to the C-type (carbonaceous) asteroids. The grooves that score the surface may have been generated in an ancient impact with a smaller asteroid that punched the end of Phobos, excavating the crater Stickney. Spacecraft Planetary Imaging Facility, Cornell University

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