Ultima Thule, the farthest cosmic body ever visited by a spacecraft, has been officially renamed Arrokoth, or "sky" in the Native American Powhatan and Algonquian languages, following a significant backlash over the old name's Nazi connotations. The icy rock, which orbits in the dark and frigid Kuiper Belt about a billion miles beyond Pluto, was visited by the NASA spaceship New Horizons in January this year, with the first detailed images showing it consisted of two spheres stuck together in the shape of a snowman. Its technical designation is 2014 MU69 but the New Horizon team initially nicknamed it Ultima...