Astronomy Fundamentals

Medieval Andrenaissance Astronomy

What is Kepler’s Third Law of planetary motion?

According to Kepler’s Third Law, the cube of the orbital distance between a planet and the Sun is directly proportional to the square of the planet’s orbital period. Kepler discovered this law in 1619, ten years after the publication of his first two laws of planetary motion. It is possible to use this third law to calculate the distance between the Sun and any planet, comet, or asteroid in the solar system, just by measuring the object’s orbital period.

Christiaan Huygens


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