In the generation following Copernicus, the question of planetary
motions was picked up by two remarkable astronomers: Tycho Brahe and
Johannes Kepler. Tycho was a Danish nobleman and brilliant astronomer
and instrument builder whose high precision naked-eye measurements of
the stars and planets were to be the summit of pre-telescopic astronomy.
Kepler was the talented German mathematician who was hired by Tycho and
succeeded him after his death who was to use Tycho's data to derive his
three laws of planetary motion. These laws swept away the vast complex
machinery of epicycles, and provide a geometric description of planetary
motions that was to set the stage for their eventual physical
explanation by Isaac Newton a generation later. Recorded 2007 Oct 10 in
1000 McPherson Lab on the Columbus campus of The Ohio State University.