# Kepler's laws of planetary motion

In astronomy, Kepler's laws of planetary motion, published by Johannes Kepler between 1609 and 1619, describe the orbits of planets around the Sun.

## Kepler's first law of planetary motion

Each planet's orbit the Sun is an ellipse. The Sun's center is always located at one focus of the orbital ellipse.

## Kepler's second law of planetary motion

A planet moves in its ellipse, so the line between it and the Sun placed at a focus cover equal areas in equal times.

## Kepler's third law of planetary motion

Kepler found another mathematical ratio relating the period of the planets to their distance to the Sun. This law states: "The square of the periods of the planets are proportional to the cubes of their distances from the Sun".