Kepler's second law
The second law of Kepler's planetary motion, also known as the law of equal area, refers to the fact that the line between the sun and the moving planets in the solar system sweeps across equal areas in equal time.
This law is one of the three Kepler laws discovered by German astronomer Johannes Kepler. Originally published in New Astronomy, published in 1609, the book also states that the law applies equally to other celestial systems that move around.
Kepler's second law is a more accurate description of the orbit of the planet, providing strong evidence for Copernicus's heliocentric theory, and providing evidence for Newton's later proof of gravitation, and together with the other two Kepler laws. The cornerstone of astronomy.