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Pluto is small, cold, and ancient — a recipe for a geriatric world where not much happens. Yet when New Horizons flew through the Pluto system in July, it found just the opposite — a world that may be active even today.
The craft flew just 8500 miles from Pluto, snapping thousands of pictures and gathering data on its temperature, composition, and much more. Because of the great distance, it’s transmitted only a fraction of those readings, with the rest trickling to Earth over the coming months.
Yet scientists have seen enough to draw some conclusions. One is that Pluto is a little bigger than thought — about 1475 miles in diameter.
New Horizons photographed mountains that may be up to two miles high, which was a bit of a surprise. Pluto’s surface was thought to consist mainly of frozen nitrogen, carbon monoxide, and carbon dioxide. Those compounds aren’t strong enough to make big mountains, though. That suggests that the mountains are made of frozen water, which is as hard as granite. In fact, the crust may consist mainly of water, with the other ices forming thin dustings atop it.
The ice displays an amazing array of features: cliffs and troughs hundreds of miles long, big glaciers, and dark streaks that may be sculpted by winds. These features mean that Pluto has been geologically active in the recent past — and may still be today. Scientists should learn more about that as they study more observations from New Horizons.
Script by Damond Benningfield, Copyright 2015