Nearer the center of the solar system, scientists reported in November that NASA's Messenger probe had discovered ice in shadowed polar craters on Mercury. The discovery is remarkable given the surface temperatures of the inner-most planet. But because there is little or not tilt in Mercury's axis, polar craters often remain permanently shadowed. Water was likely brought by asteroids crashing into Mercury during the formation of the solar system.
(Source: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington)