Our own moon, the thinking goes, formed when a huge rock slammed into the Earth billions of years ago. Is the same true of one of Mars’ dual moons?
The Martian moon Phobos hides an unknown history. One idea has been that the 12-mile by 17-mile rock came from the nearby asteroid belt, and Mars’ gravity captured it. However, new evidence from the European Space Agency’s explorer Mars Express suggests that the stuff of Phobos is more Mars-like than asteroid-like, and therefore its origin goes back to a violent collision that knocked material from Mars into its own orbit. That material would have eventually coalesced into Phobos.
The European Space Agency has released the latest pictures of the Martian moon Phobos, taken by the European Mars Express (MEX) probe during its recent flybys. On one flyby, MEX skimmed just 42 miles above the surface of Phobos, which is the closest any manmade object has ever gotten to the little Martian moon.
The image above is from a flyby that brought MEX within 63 miles of the surface; its High Resolution Stereo Camera took photographs that have a resolution of 14 feet per pixel. The images are being scrutinized by the Russian space agency as it tries to settle on a landing site for its ambitious Phobos-Grunt mission next year–the two potential landing sites are marked by red dots in the picture above. The Phobos-Grunt mission aims to collect a soil sample from Phobos, and then to return the sample to Earth for analysis.