Wired Science posts images from NASA's orbiting spacecraft, Messenger, that show huge lava flows likely carved the long channels and teardrop-shaped hills shown here. The lava may have come from volcanic vents seen in the lower-left image.
Ground-based radar has revealed very reflective material — much like water ice — sitting in deep craters at Mercury’s north pole.
Oddly shaped dips surrounded by very bright material, shown here in Mercury's Raditladi basin, are a brand-new puzzle. Scientists have so far identified about three dozen of these markings inside impact craters at all latitudes and terrains on the planet. But how they formed is still a mystery.