Kepler’s Laws of planetary motion.

Ellipse lab

Tycho Brahe

• Tycho Brahe was a Danish astronomer who is best known for the astronomical observations which led Kepler to his theories of the Solar system

• Most precise observational equipment of time

• Detailed observation of the movement of Mars which helped Kepler formulate his laws on planetary motion

• Thought earth was the center of the solar system

Johannes Kepler

• a German mathematician and astronomer

• Student of Tycho Brahe

• discovered that the Earth and planets travel about the sun in elliptical orbits.

• He gave three fundamental laws of planetary motion.

Kepler’s 1st law of planetary motion

• I. The orbits of the planets are ellipses, with the Sun at one focus of the ellipse. – Sun one of the foci

points– 2nd foci – nothing there– Distance from sun is

constantly changing

Kepler’s second law of planetary motion

• The lines joining the planet to the sun sweeps out equal areas in equal times– Planet moves faster

when it is near the sun– Perihelion – nearer sun– Aphelion – farther from

sun

Kepler’s third law of planetary motion

• Time it takes a planet to revolve around the sun increases with the size of its orbit.

http://csep10.phys.utk.edu/astr162/lect/binaries/visual/kepleroldframe.html