Kepler's Laws

Kepler's Laws of Planetary Motion: Kepler's First Law (1609): The orbit of a planet about a star is an ellipse with the star at one focus. Kepler's Second Law (1609): A line joining a planet and its star sweeps out equal areas during equal intervals of time. Kepler's Third Law (1618): The square of the sidereal period of an orbiting planet is directly proportional to the cube of the orbit's semimajor axis. Kepler's first law(the law of …

…resembles the shape of a circle. In fact, a circle is the special case of an ellipse in which the two foci are at the same location. Kepler's Second Law(the law of equal areas): It describes the speed of any planet movement while it is in the suns orbit. The speed constantly changes. A planet moves fastest when it is close to the sun and moves slow when it is further from the sun.