Saturn moon's yin-yang surface explained
Imagine a powdered sugar doughnut hole plowing through a cloud of dark-chocolate dust. The resulting two-colored treat would resemble one of Saturn’s weirder moons, Iapetus — an icy world with a coal-black face and a bright white backside.
For centuries astronomers have puzzled over the source of this yin-yang color pattern. Now a team led by graduate student Daniel Tamayo of Cornell offers an explanation: Dust flung from another