08/02/2021
There are mountains on Pluto
Pluto is a tiny world at the edge of the solar system, so at first it was thought that the dwarf planet would have a fairly uniform environment. That changed when NASA's New Horizons spacecraft flew by there in 2015, sending back pictures that altered our view of Pluto forever. [Destination Pluto: NASA's New Horizons Mission in Pictures]
Among the astounding discoveries were icy mountains that are 11,000 feet (3,300 meters) high, indicating that Pluto must have been geologically active as little as 100 million years ago. But geological activity requires energy, and the source of that energy inside Pluto is a mystery. The sun is too far away from Pluto to generate enough heat for geological activity, and there are no large planets nearby that could have caused such disruption with gravity.