Kepler's Laws of Planetary Motion

The Laws of Planetary Motion (1619) by Johannes Kepler. Kepler's First Law: I. The orbits of the planets are ellipses, with the Sun at one focus of the ellipse. Kepler's First Law is illustrated in the image shown. The Sun is not at the center of the ellipse, but is instead at one focus (generally there is nothing at the other focus of the ... ................
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