﻿For 85 years, it was little more than a featureless grey blob on classroom maps of the solar system, but, on 15 July, Pluto was seen in high resolution for the first time, revealing dramatic mountain ranges made from solid water ice on a scale to rival the Alps or the Rockies. 
The extraordinary images of the former ninth planet and its large moon, Charon, beamed 4bn miles back to Earth from the New Horizons spacecraft, mark the climax of a mission that has been quietly underway for nearly a decade. 
Alan Stern, the mission’s principal investigator, described the images as a “home run” for the team. “New Horizons is returning amazing results already. The data look absolutely gorgeous, and Pluto and Charon are just mind-blowing.” 
One of the biggest surprises was the discovery that “there are mountains in the Kuiper belt ”, the solar system’s mysterious “third zone” where Pluto sits amid around 100,000 smaller icy objects. John Spencer, a mission scientist, said the mountains appear to be around 11,000ft high and several hundred miles across. “These are pretty significant mountains.” 
The detailed image of one edge of the dwarf planet showed not a single crater, hinting that the surface has been recently “paved over” by geological activity, which could include dramatic geysers blasting plumes of ice into the atmosphere or cryo-volcanoes that erupt in explosions of ice rather than molten rock.