The science team of NASA’s New Horizons mission has produced this global map of Pluto’s largest moon, Charon. The map includes all available resolved images of the surface acquired between 7-14 July 2015, at pixel resolutions ranging from 40 kilometres (24 miles) on the anti-Pluto facing hemisphere (left and right sides of the map), to 400 metres (1,250 feet) per pixel on portions of the Pluto-facing hemisphere – the side facing the New Horizons spacecraft when it flew past the dwarf planet – at map centre. Many additional images now stored on the spacecraft’s digital data recorders are expected to be transmitted “home” in later this year and these will be used to complete the global map. The map is in simple cylindrical projection, with zero longitude (the Pluto-facing direction) in the centre.
A subsurface ocean lies deep within Saturn’s moon Dione, according to new data from the Cassini mission. Two other moons of Saturn, Titan and Enceladus, are already known to hide global oceans beneath their icy crusts. Researchers believe that Dione’s crust floats on an ocean several tens of kilometres deep located 100 kilometres below the surface.