On 14 March 1964 Richard Feynman, one of the greatest scientific thinkers of the 20th Century, delivered a lecture entitled ‘The Motion of the Planets Around the Sun‘. The talk covered Johannes Kepler’s first law of planetary motion in a way no other lecture has done.

For thirty years this remarkable lecture was believed to be lost. But now Feynman’s work has been reconstructed and explained in meticulous, accessible detail, together with a history of ideas of the planets’ motions. The result is a vital and absorbing account of one of the fundamental puzzles of science, and an invaluable insight into Feynman’s charismatic brilliance.

This video recounts a lecture by Richard Feynman giving an elementary demonstration of why planets orbit in ellipses. See the excellent book by Judith and David Goodstein, “Feynman’s lost lecture”, for the full story behind this lecture, and a deeper dive into its content.

Feynman’s Lost Lecture: The Motions of Planets Around the Sun: Motion of Planets Around the Sun