Christiaan Huygens

1629 - 1695

was a Dutch physicist, leading natural philosopher between Descartes and Isaac Newton, was regarded as one of the most important figures of the Scientific Revolution. 

Huygens made original contributions to Optics and to Mechanics. He is also known for his astronomical observation of the rings of Saturn and the discovery of its moon Titan on March 25, 1655. Huygens, with the help of his brother, began to build telescopes around 1650. They discovered the first observed moon that orbits Saturn with one they built. It was the 6th moon ever discovered, after the Earth's moon and the four Galilean moons of Jupiter. 

Huygens was able to identify the correct laws of elastic collisions in work that he completed in 1656, but was published posthumously in 1703. 

Huygens also coined the term 'centrifugal force' in his 1659 work De Vi Centrifuga. 

In 1656, Huygens built the first pendulum clock. 

Huygens, also is known in Optics, for describing a wave theory of light.