April 14, 1629 – Birth of Christiaan Huygens, his principle was the basis of the wave theory of light

Christiaan Huyges, son of Constantin Huygens, one of the leading classical poets of the Dutch Golden Age, and Suzanna van Baerle, was born in The Hague on April 14, 1629.

Huyges, the second of five brothers, studied law and mathematics at the University of Leiden from 1645 to 1647, and at the Orange College in Breda from 1647 to 1649.

His numerous scientific discoveries, the fruit of his astronomical observations, and his mathematical publications gave him recognition among 17th-century European scientists.

Among his findings, the Huygens principle stands out, from which he developed the wave theory of light. According to this principle, every point on an advancing wave front acts as a source of new waves.

In 1655, thanks to the discovery of a new method for polishing lenses that allowed him to obtain sharper telescopic images, he discovered Saturn's largest satellite, Titan. He called it that because of its large size, inspired by Greek mythology. The Titans were the children of Uranus (heaven) and Gaea (earth).

In 1656, he discovered one of the brightest gas nebulae that can be seen in the sky, the Orion Nebula. That same year he invented a telescope eyepiece that bears his name. But his curiosity did not end here. The need for an exact measure of time led him to use the pendulum to regulate the movement of clocks. Huygens was appointed a Fellow of the Royal Society of London in 1963.

In 196.5 he created the first pocket watch thanks to the development of the spiral spring. In addition, he built a portable chronometer that made it easy for sailors to determine geographic longitude at sea.

In 1966, when the French Academy of Sciences was created and invited to participate in it, he moved to Paris where he stayed until 1681, when he returned to his native city. There he was also an astronomer at the Observatory.

In 1673 he published his famous study on The Pendulum Clock, which included complete solutions to problems such as the oscillation period of a simple pendulum and the laws of centrifugal force for uniform circular motion.

In 1678, he discovered the polarization of light through double refraction in calcite.

The development of the wave theory of light was Huygens' greatest achievement. This theory, described in Traité de la lumière (1690), made it possible to explain the phenomena of reflection and refraction of light better than Newton's corpuscular theory.

Christiaan Huygens died on July 8, 1695 in The Hague.