Mercury, the lowest and inmost earth in our solar system, orbits the Sun at a distance of just 57.9 million kilometers. Despite its propinquity to the Sun, it remains shrouded in riddle. As the first earth from the Sun, Mercury is a rocky world of axes. It has no substantial atmosphere to retain heat, so its face gests drastic temperature oscillations. Ancient, cratered, and fairly unchanged for billions of times, Mercury presents a window into the early solar system.