Spectral fingerprints of Phobos' surface support an ancient big crash origin for the Martian moon Date: September 24, 2018 Source: American Geophysical Union Summary: Phobos, the larger of Mars' two tiny satellites, is the darkest moon in the solar system. This dark aspect inspired the hypothesis that the close-orbiting moon may be a captured asteroid, but its orbital dynamics seemed to disagree. A new study suggests Phobos' composition may be more like the volcanic crust of the Red Planet than it appears, consistent with an origin for the moon in an ancient, violent impact on Mars.
