Kepler's 3rd Law Calculator
Calculate the orbital period of a planet based on its average distance from the Sun.
1 AU = Earth's average distance from the Sun.
Kepler's Third Law
Johannes Kepler's third law of planetary motion states that the square of the orbital period of a planet is directly proportional to the cube of the semi-major axis of its orbit.
Harmonic Law
In our solar system, this is expressed simply as P² = a³. This law reveals that planets further from the Sun not only have longer paths to travel but also move slower in their orbits.
Frequently Asked Questions (FAQ)
What is an AU?
An Astronomical Unit (AU) is the average distance from the Earth to the Sun, about 150 million kilometers.
Does this apply to moons?
Yes, the general form of Kepler's 3rd law applies to any body orbiting another massive body, though the constant of proportionality changes based on the mass of the central body.