# Johannes Kepler

Topics: Kepler's laws of planetary motion, Isaac Newton, Planet Pages: 2 (683 words) Published: May 30, 2007
The Kepler Idea: Circles and Stars
Johannes Kepler was one of the most important scientist of the Scientific Revolution in the middle ages. Kepler was a German astronomer and mathematician of the late 1600's and early 1700's. He proved all the planets orbit the sun, and not the sun orbiting the earth. Kepler created three laws, in which he describes the governing motion of the planets. He was committed passionately to circles. He also became the founder of modern optics. Kepler did not face that many democratic challenges, such as many others did. His achievements proved many things in which today's modern scientists use.

Kepler discovered one of the most famous discoveries of astronomy. Planets orbit the sun. The sun does not orbit the planets. He posed a question of the planetary motion. Later, Newton took to answer. Kepler also came across the paths of planets. Their path was elliptical, not circular. Planets move in ellipses with the sun at one focus. Prior to this in 1602, Kepler found from trying to calculate the position of the Earth in its orbit that as it sweeps out an area defined by the Sun and the orbital path of the Earth that the radius vector describes equal areas in equal times. This idea became a very popular in the Scientific Revolution, as it aroused much questioning.

Three laws of planetary motion were created by Kepler. The first law is that planets describe elliptic orbits with the sun. This law was announced in 1605, after his major discovery of how the planets orbit, or move. The second law is: the line joining the planet nearer to the sun sweeps in equal areas in equal times. For an object along an elliptical orbit to sweep out the area at a uniform rate, the object moves faster when the radius vector is short and the object moves slower when the radius vector is long. Lastly, the third law is: the squares of the periodic times are to each other as the cubes of the average distances. This law was published in 1619. Newton's laws of...

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