# What is kepler’s 3rd law

## What does Kepler’s 3rd law mean?

604K subscribers. Kepler’s 3rd Law is sometimes called The Law of Periods: The square of the period of any planet is proportional to the cube of the semimajor axis of its orbit.

## What are Kepler’s 3 Laws Why are they important?

Explanation: Kepler’s laws describe how planets (and asteroids and comets) orbit the sun. They can also be used to describe how moons orbit around a planet. But, they do not just apply to our solar system — they can be used to describe the orbits of any exoplanet around any star.

## What is meant by Kepler’s law?

any one of three laws governing planetary motion: each planet revolves in an ellipse, with the sun at one focus; the line connecting a planet to the sun sweeps out equal areas in equal periods of time (law of areas ); or the square of the period of revolution of each planet is proportional to the cube of the semimajor …

## What equation is used for Kepler’s 3rd law?

Kepler’s 3rd Law: P2 = a. 3

Kepler’s 3rd law is a mathematical formula. It means that if you know the period of a planet’s orbit (P = how long it takes the planet to go around the Sun), then you can determine that planet’s distance from the Sun (a = the semimajor axis of the planet’s orbit).

## How do you derive Kepler’s third law?

Kepler’s third law can be derived from Newton’s laws of motion and the universal law of gravitation. Set the force of gravity equal to the centripetal force. After substituting an expression for the velocity of the planet, one can obtain: GMr=4πr2P2 which can also be written P2=4π2a3GM.