How did Kepler propose the planets moved?

Answer 1

By this: The orbit of every planet is an ellipse with the sun at one of the foci. An ellipse is characterized by its two focal points; see illustration. Thus, Kepler rejected the ancient Aristotelean and Ptolemaic and Copernican belief in circular motion. A line joining a planet and the sun sweeps out equal areas during equal intervals of time as the planet travels along its orbit. This means that the planet travels faster while close to the sun and slows down when it is farther from the sun. With his law, Kepler destroyed the Aristotelean astronomical theory that planets have uniform velocity. The squares of the orbital periods of planets are directly proportional to the cubes of the semi-major axes (the "half-length" of the ellipse) of their orbits. This means not only that larger orbits have longer periods, but also that the speed of a planet in a larger orbit is lower than in a smaller orbit.

Answer 2

While studying astronomical tables describing the motions of Mars projected on the sky, Johannes Kepler discovered three laws that govern the orbits of the planets. Kepler found that all of the planets follow elliptical orbits and that the greater the distance between a planet and the Sun, the slower the planet orbits. As well as transforming understanding of astronomy, Kepler's three laws laid the foundations for Isaac Newton's law of gravity.Kepler's Three Laws:First Law: Planetary orbits are elliptical with the Sun at one focus.Second Law: A planet sweeps out equal areas in equal times as it orbits the Sun.Third Law: The orbital periods scale with ellipse size such that the period squared is proportional to the semi-major axis length cubed.Patterns in Nature:Johannes Kepler lived during a time when astrology was taken very seriously but the study of astronomy was still in its infancy. It was a time when religious and spiritual ideas were just as important in revealing the laws of nature as observation was. Kepler believed that the underlying structure of the universe was built from perfect geometric forms and devoted his life to trying to find patterns of perfect polygons hidden in nature's work.Read more: http://physics-history.suite101.com/article.cfm/keplers_laws#ixzz0Vua5ZmVi

Answer 3

Kepler used Tycho Brahe's observations and measurements to deduce that all the planets move in elliptical orbits. Before that they were believed to move on offset circles, that is circles with the Sun offset from the centre.

He made his breakthrough by studying the orbit of Mars, which has one of the more elliptical orbits. Great accuracy was needed in the measurements and the calculations to arrive at Kepler's three laws of planetary motion.

Answer 4

Theology at first, but then he became a math professor. He later applied theology and math to astronomy.

Answer 5

What did Kepler discover about the orbits of the planets