Smallest Planet Yields Big Surprises. Thin Skinned and Wrinkled, Mercury is Full of Surprises. Want to stay on top of all the space news?
Follow @universetoday on Twitter A global mosaic of Mercury from MESSENGER. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington Until relatively recently, Mercury was one of the most poorly understood planets in the inner solar system. Frozen Water Found in Scorching Hot 752F Mercury Hell.