ASTR 3 Lecture Notes - Lecture 3: Nicolaus Copernicus, Orbital Period, Supernatural
Document Summary
Daily timekeeping, track seasons, make accurate calendars, monitor lunar cycles, monitor plants/stars. Our mathematical and scientific heritage originated with the civilizations of the middle east (mesopotamia, egypt. Greeks were the first people to make models of nature. Eratosthenes (240 bc) measured the circumference of the earth. Aristarchus of samus (310 230 bc) proposed heliocentric model; calculated relative distances to and sizes of the. Model = simplified but significant conceptual description of nature. Tried to explain patterns in nature w/o resorting to myth/supernatural. Greeks taught that earth was a sphere as early as ~500bc. Planets, like the sun, usually appear to move eastward relative to the stars. But as we pass them by in our orbit, they move west relative the stars for a few weeks or month, called retrograde motion. Retrograde motion occurs when we lap another planet (or when mercury/venus lap us) as earth orbits the sun only easy to explain w/ a heliocentric model.
