AST-A 100 Lecture Notes - Lecture 1: Apparent Retrograde Motion, Natural Philosophy, Geocentric Model
Document Summary
Assigns meaning to the sun traveling through. Sky appears as a great hollow dome with stars on the surface: this dome is referred to as the celestial sphere, zenith top of dome, horizon where dome appears to meet the earth. Stars the sun and the moon all rise in the east and set in the west. Objects in the sky appear to be at the same distance. Looks like the dome of the sky is moving. Sky is divided into 88 regions around identifiable star patterns. Patterns are only a matter of perspective and stars in constellations are far from each other. Natural philosophers demonstrated that the earth was a sphere as early as the 3rd century bc. Natural philosophers had proposed the heliocentric model as early as the 3rd century bc. Explained apparent retrograde motion without epicycles: ret(cid:396)og(cid:396)ade (cid:373)otio(cid:374) does(cid:374)"t a(cid:272)tuall(cid:455) happe(cid:374) The planets move along the ecliptic because they live in the plane of the solar system.
