EurekAlert!
The origin and nature of Mars is mysterious. It has geologically distinct hemispheres, with smooth lowlands in the north and cratered, high-elevation terrain in the south. The red planet also has two small oddly-shaped oblong moons and a composition that sets it apart from that of the Earth.
New research by University of Colorado Boulder professor Stephen Mojzsis outlines a likely cause for these mysterious features of Mars: a colossal impact with a large asteroid early in the planet’s history. This asteroid—about the size of Ceres, one of the largest asteroids in the Solar System—smashed into Mars, ripped off a chunk of the northern hemisphere and left behind a legacy of metallic elements in the planet’s interior. The crash also created a ring of rocky debris around Mars that may have later clumped together to form its moons, Phobos and Deimos.
