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 to protect Pluto; perturbations from the planets (especially Neptune) could alter Pluto's orbit (such as its orbital precession) over millions of years so that a collision could be possible. However, Pluto is also protected by its 2:3 orbital resonance with Neptune: for every two orbits that Pluto makes around the Sun, Neptune makes three. Each cycle lasts about 495 years. This pattern is such that, in each 495-year cycle, the first time Pluto is near perihelion, Neptune is over 50° behind Pluto. By Pluto's second perihelion, Neptune will have completed a further one and a half of its own orbits,