Pluto has a deep layer of solid nitrogen and other volatile ices. These things are key to understanding the activity on Pluto. Sputnik Planum is a 620 mile wide basin found on the left side of Tomboaugh Regio. This formation holds a deep layer of the said elements. "Pluto has greatly exceeded our expectations in diversity of landforms and processes - processes that continue to the present," Alan Howard of the University of Virginia at Charlottesville, who is working with New Horizons' Geology, Geophysics, and Imaging (GGI) team, explained.