ASTR 1210 Lecture Notes - Lecture 9: Sidereus Nuncius, Hans Lippershey, Nicolaus Copernicus
27 Aug 2016
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Demonstrated that the earth was round (aristotle, ca. Measured, accurately, the size of the earth (eratosthenes, ca. Detected the precision of the earth"s polar axis (hipparchus, ca. Developed a geocentric model of the solar system (ptolemy, ca. Nicolaus copernicus (1473-1543) argued that the motion of the sun and planets could be equally described by a sun centered system. Natural explanation for the annual motion of the sun against the background stars. Natural explanation for motion of venus and mercury relative to the sun. But: not more accurate than ptolemaic tab. Tycho noticed that tables based on ptolemaic and copernican system could not accurately reproduce the motions of the planets. For more than 20 years he measured the positions of the sun, moon, and planets with unprecedented accuracy. Tycho rejected the copernican system because he could not measure the parallax of mars. He adopted a system where the planets orbit the earth, but the sun orbits the earth.
