Space exploration on 16 June 1963. China first launched a person into space 42 years after the launch of "Vostok 1", on 15 October 2003, with the flight of Yang Liwei aboard the "Shenzhou 5" (Divine Vessel 5) spacecraft. The first artificial object to reach another celestial body was Luna 2 in 1959. The first automatic landing on another celestial body was performed by Luna 9 in 1966. Luna 10 became the first artificial satellite of the Moon. The first crewed landing on another celestial body was performed by Apollo 11 on 20 July 1969. The first successful interplanetary flyby was the
Dynamics of the celestial spheres individual unmoved mover would be required to insure each individual motion in the heavens. While stipulating that the number of spheres, and thus gods, is subject to revision by astronomers, he estimated the total as 47 or 55, depending on whether one followed the model of Eudoxus or Callippus. In "On the Heavens", Aristotle presented an alternate view of eternal circular motion as moving itself, in the manner of Plato's world-soul, which lent support to three principles of celestial motion: an internal soul, an external unmoved mover, and the celestial material (aether). In his "Planetary Hypotheses", Ptolemy (c.90–168) rejected the