Edmond Halley (1656 – 1742)

Edmond Halley (1656 – 1742)

He spent most of his time on lunar observations, but was also interested in the problems of gravity. One problem that attracted his attention was the proof of Kepler's laws of planetary motion.

Kepler's First Law

The first law says: "The orbit of every planet is an ellipse with the sun at one of the foci." The mathematics of the ellipse is as follows. The equation is where (r,θ) are heliocentric polar coordinates for the planet, p is the semi latus rectum, and ε is the eccentricity, which is less than one.

My hometown monk in Tang Dynasty already discovered planetary motion, nearly a thousand years before Halley. He is the real world class scientific giant.