Forgotten Planet
Mercury: The solar system's inner frontier
By Ron Cowen
Not far from the sun lies a tiny planet with a big image problem. A fleeting presence often hidden by the sun’s glare, Mercury is the neglected child of the solar system.
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Planetary scientists have preferred to gaze upon more exotic-looking orbs than pockmarked Mercury, whose appearance bears a superficial resemblance to the moon’s familiar facade. Only one mission, Mariner 10, has flown past the planet, and it viewed less than half the surface.