Saturn's rings observed by Christian Huygens in 1659. No one had ever seen Saturn this way before. Christiaan Huygens, (1629-1695) a prominent Dutch mathematician, astronomer, physicist and horologist. His work included early telescopic studies elucidating the nature of the rings of Saturn and the discovery of its moon Titan, the invention of the pendulum clock and other investigations in timekeeping, and studies of both optics and the centrifugal force. Huygens is seen as the first theoretical physicist as he was the first to use formulae in physics.