Template:Selected anniversaries/January 3
1641: Astronomer Jeremiah Horrocks dies. He was the first person to demonstrate that the Moon moved around the Earth in an elliptical orbit.
1777: Mathematician and physicist Louis Poinsot born. Poinsot will invent geometrical mechanics, showing how a system of forces acting on a rigid body can be resolved into a single force and a couple.
1819: Astronomer Charles Piazzi Smyth born. Smyth will make innovations in astronomy, and make pyramidological and metrological studies of the Great Pyramid of Giza.
1967: Premiere of "The Trouble With Triffids", one of the "Forbidden Episodes" of the television series Star Trek.
2016: Computer scientist, astronomer, and academic Peter Naur dies. His main areas of inquiry were design, structure and performance of computer programs and algorithms.