Kepler's laws

British  

plural noun

1. three laws of planetary motion published by Johannes Kepler between 1609 and 1619. The first states that the orbit of a planet describes an ellipse with the sun at one focus. The second states that, during one orbit, the straight line joining the sun and a planet sweeps out equal areas in equal times. The third states that the squares of the periods of any two planets are proportional to the cubes of their orbital major axes

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Example Sentences

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Kepler's laws

We have seen that Kepler’s laws, which do not take into account the gravitational effects of the other planets on an orbit, really work quite well.

From Textbooks ● Oct. 13, 2016

A ring is a collection of vast numbers of particles, each like a tiny moon obeying Kepler’s laws as it follows its own orbit around the planet.

From Textbooks ● Oct. 13, 2016

Although only 1.5 kilometers in diameter, smaller than many college campuses, Dactyl provides scientists with something otherwise beyond their reach—a measurement of the mass and density of Ida using Kepler’s laws.

From Textbooks ● Oct. 13, 2016

Still, Kepler’s laws are purely descriptive: they do not help us understand what forces of nature constrain the planets to follow this particular set of rules.

From Textbooks ● Oct. 13, 2016

When we send spacecraft to the planets, when we observe double stars, when we examine the motion of distant galaxies, we find that throughout the universe Kepler’s laws are obeyed.

From "Cosmos" by Carl Sagan