Kepler's Third Law
Kepler's Third Law
Kepler's third law states that the square of the period of revolution of a planet is proportional to the cube of the semimajor axis of the planet's elliptical orbit around the Sun. In symbols, ∝ or =k. The constant can be taken as 1 for simplicity, equivalent to measuring in years and in astronomical units. In this Demonstration the ellipses have different eccentricities; the value of is chosen to equal 5, so that the period is equal to ≃11.18.
P
a
2
P
3
α
2
P
3
α
k
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α
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5