As the Messenger spacecraft passed Mercury a few weeks ago, it snapped a number of high-quality images that shed new light on the planet. Unlike our moon, to which Mercury had been previously compared, these new pictures show a number of ancient, dormant volcanoes; massive, sheer cliffs; and a network of fissures that indicate patterns of fault activity not unlike those here on Earth. Also discovered was the formation seen in the above image, which scientists have begun to call the Spider. It is a large, central depression with over 100 narrow troughs radiating outward — a geological curiosity never before seen in our solar system.
The Messenger will pass by the planet twice more before settling into orbit around 2011, and scientists hope that the coming years will reveal information about Mercury’s origin and its strong magnetosphere, a characteristic which is shared with Earth only. (via the Washington Post.)