PUZZLED BY PLUTO. (cover story)

The article focuses on the planet Pluto explored by the U.S. National Aeronautics & Space Administration (NASA) New Horizons spacecraft. Topics include the planet having four small moons, Nix, Hydra, Kerberos, and Styx which are as old as the planet, features within the nitrogen glacier Sputnik Planitia (SP) forming the western lobe such as recharge zones and glacial flow; and temporal changes on the planet's surface the ice moves sliding under some of the mountains SP abuts.