Walter Frederick Morrison disc more cheaply. In 1955, he and Lu designed the Pluto Platter, the archetype of all modern flying discs. On January 23, 1957, they sold the rights for the Pluto Platter to the Wham-O toy company. Initially Wham-O continued to market the toy solely as the "Pluto Platter", but by June 1957 they also began using the name "Frisbee" after learning that college students in the Northeast were calling the Pluto Platter by that name. Morrison also invented several other products for Wham-O, but none were as successful as the Pluto Platter. Morrison and his wife, Lu Nay Morrison had
Pluto throughout the 20th century. Astronomers initially calculated its mass based on its presumed effect on Neptune and Uranus. In 1931, Pluto was calculated to be roughly the mass of Earth, with further calculations in 1948 bringing the mass down to roughly that of Mars. In 1976, Dale Cruikshank, Carl Pilcher and David Morrison of the University of Hawaii calculated Pluto's albedo for the first time, finding that it matched that for methane ice; this meant Pluto had to be exceptionally luminous for its size and therefore could not be more than 1 percent the mass of Earth. (Pluto's albedo is