Christiaan Huygens

Huygens, Christiaan (1629–95), Dutch scientist. He formulated a wave theory of light, first applied the pendulum to the regulation of clocks, and discovered the surface markings of Mars and the rings of Saturn. In his optical studies he stated Huygens's Principle, that all points on a wave front may at any instant be considered sources of secondary waves that, taken together, represent the wave front at any later instant. Huygens' theory of light states that light is a disturbance traveling through some medium, such as the ether. Thus light is due to wave motion in ether.

See also: Optics; Physics.