# Explain Kepler's laws.

## Question:

Explain Kepler's laws.

## Johannes Kepler in Astronomy:

Johannes Kepler had endless enthusiasm for researching the Solar System. Kepler used his teacher, Tyco Brache's enormous astronomical data to create his three laws to explain the planetary motion in our solar system.

Kepler established three important empirical laws of planetary motion-- the law of elliptical orbit, the law of areas, and the law of the relation between period and distance--- to describe and understand the motion of the Solar System.

The first law is known as the law of ellipses. The orbit of each planet is an ellipse with the sun at one focus. The shape of the planets' orbit is an ellipse.

The second law is known as the law of areas. The radius vector to a planet sweeps out equal areas in equal intervals of time. When a planet is closer to the sun, it revolves faster, and, on the other hand, when a planet is further away from the sun, it revolves slower.

The third law is known as the law of harmony. The squares of the sidereal periods of the planets are proportional to the cubes of the semi-major axis (mean radii) of their orbits. Here, the sidereal period is the time it takes the planet to complete one orbit of the Sun with respect to the stars.