📂Classical Mechanics

Kepler's Laws of Planetary Motion

Kepler’s Laws of Planetary Motion¹

The Kepler’s laws are empirical laws formulated by compiling and analyzing the observation records of astronomers such as Tycho Brahe and Hipparchus. They greatly contributed to the derivation of Newton’s Law of Universal Gravitation. Conversely, Kepler’s laws could be mathematically explained through the Law of Universal Gravitation and Newton’s Laws of Motion.

First Law: The Law of Ellipses

The orbit of a planet is an ellipse with the sun at one of the foci.

Second Law: The Law of Equal Areas

A line connecting the sun and a planet covers equal areas during equal intervals of time.

Third Law: The Harmonic Law

The square of the orbital period of a planet is proportional to the cube of the semi-major axis of its orbit.