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Pluto is distinguished by properties other than its size, and its representation in “Nine planets, or eight?” as just another gray ball was misleading. It has the most contrasting surface known in the solar system (bright nitrogen ice caps and dark carbonaceous equatorial areas). To understand the processes ongoing on Pluto’s surface and within its atmosphere and interior, we look primarily (though not exclusively) to planetary analogs-not asteroids or comets or other Kuiper Belt objects, for that matter.