Chapter 20 planetary motion
Earth’s position in space – how has it changed over thousands of years…. Background: Pre-1500’s – Geocentric model of the universe (Earth- center) Models.
The Sun
(B EFORE THE R ENAISSANCE ) T HEOCRACY A theocracy is a form of government where religious rulers run the government. Prior to the beginning of the Renaissance,
Reddening and Extinction The discovery of the dust is relatively recent. In 1930 R.J. Trumpler (lived 1886--1956) plotted the angular diameter of star.
