The Mars Express spacecraft snapped the closest pictures ever taken of Phobos, the irrregularly shaped largest of the two moons orbiting the Red Planet. The European Space Agency probe is taking lots of pictures, helping scientists figure out if Phobos is an asteroid captured from the nearby asteroid belt, or if it's left over from the ancient days when planets were made in the solar system.
Another intriguing possibility is that Phobos is not really a solid object, but a floating pile of rubble that's narcissistically attracted to itself by gravity. Either way, it's more of a rock than a moon, with dimensions of 17 x 14 x 12 miles.
Rock or no, Russia wants to send a robot craft on a trip to this odd boulder, and the Mars Express is helping out, giving the most detailed pictures yet of possible landing sites. Expect even better pictures than this, too: There's another camera onboard the Mars Express that scientists might use on a future flyby, rocking resolution that's a mere meter across.