Kirkwood, Daniel (1814–1895)

Daniel Kirkwood

Daniel Kirkwood was an American astronomer best known for his discovery (1866) of radial gaps in the main asteroid belt, now known as Kirkwood gaps. Kirkwood was also the first to account for the Cassini and Encke Divisions in Saturn's rings in terms of orbital resonances with the planet's larger moons, and to propose the existence of a group of sun-grazing comets.