Johannes Kepler

German astronomer, mathematician, and optician, who discovered the laws of planetary motion named after him. He showed that planets move in elliptical orbits with variable speed, and established a mathematical relationship between the orbital period and the distance from the Sun. His work became the foundation for Newton's theory of gravity. He also contributed to optics and stereometry.

Biography

Born in Weil der Stadt. Studied at the University of Tübingen, where he became a supporter of Copernicus' teachings. Worked as an assistant to Tycho Brahe, after his death inherited the most precise astronomical observations. Imperial mathematician in Prague under Rudolf II. Author of books 'New Astronomy', 'Harmonices Mundi'.

Key discoveries

Three laws of planetary motion (Kepler's laws): 1) planets move in ellipses with the Sun at one focus; 2) in equal intervals of time, the radius vector sweeps out equal areas (law of areas); 3) the squares of the orbital periods of planets are proportional to the cubes of the semi-major axes of their orbits.
Optical theory — explained the functioning of the human eye and described the refraction of light in lenses.
Kepler's Supernova — observed and described the outburst of a supernova, proving that changes occur even in the realm of the 'eternal' stars.
Keplerian telescope — proposed a telescope design with two convex lenses.

💡 Kepler believed in the 'music of the spheres' and sought harmonic relationships between the orbits of the planets, trying to fit them into a system of polyhedra.

Quote: "'I wrote a book so that it would be read by contemporaries or descendants — it doesn't matter. It can wait hundreds of years for its reader, if God himself waited six thousand years to see his spectator.'"

Biography

Key discoveries

Related articles