Planetary scientists at the University of Arizona say they have discovered an entirely new type of cosmic collision. Pluto and Charon are the largest binary system in the known population of trans-Neptunian objects in the outer Solar System. Their shared external orbital axis suggests a linked evolutionary history and collisional origin. Their radii, 1,200 km and 600 km, respectively, and Charon’s wide circular orbit of about 16 Pluto radii...
