This annotated view of a portion of Pluto’s Sputnik Planum (Sputnik Plain), named for Earth’s first artificial satellite, shows an array of enigmatic features. The surface appears to be divided into irregularly shaped segments that are ringed by narrow troughs, some of which contain darker materials. Features that appear to be groups of mounds and … Continue reading "Youthful Frozen Plains Cover Pluto’s Big ‘Heart’ – Spectacular New Images from New Horizons"