New Evidence Supports Asteroid Origin Of Martian Moon

Study uses reflected light to compare chemical makeup of moon and other asteroids. Phobos, with Mars in the background. jihemD via wikimedia commons, rights New research suggests that Mars' larger moon, Phobos, is likely an errant asteroid trapped by the planet's gravitational pull. Astronomers matched the chemical makeup of Phobos' surface to a meteorite that struck Canada, concluding that the Martian moon likely started out as a carbon-rich, "D-type" asteroid that drifted too close to the red ...