(April 14, 1629 – July 8, 1695)
Christiaan Huygens explored maths, physics, horology, and even philosophy. He admired Pierre de Fermat, corresponded with him, as well as with Blaise Pascal, René Descartes, and other leading researchers of his era. He also taught a young Gottfried Leibniz mathematics. After studying Galileo’s works, Huygens built the first pendulum clock. The accuracy of this invention ensured that it remained in vogue for nearly three centuries. (From the 1650s until the 1930s when quartz took over, pendulum clocks were the most accurate man-made timepieces). He is also credited with developing balance-spring-watch independently of Robert Hooke. Regarding optics, Huygens presented his Wave Theory of Light to an erudite forum at the Paris Academy of Science, who appreciated it. His skills as a lens-maker enabled him to exchange ideas with Baruch Spinoza and Antonie van Leeuwenhoek. With the telescopes he built, he was able to study Mars: before focusing on Saturn, its rings and its moon (named Titan). His contributions to mathematics were mostly in the fields of Geometry, Algebra and Statistics. These included his Applied Maths researches on the motions of objects, their impacts upon collisions, as well as gravity. Christiaan Huygens was not an avid publisher of works; yet, he is credited with publishing the first known book on Probability Theory: after learning the theme from Fermat and Pascal. His other treatises pertained mostly to astronomy and optics. Among the items dedicated in his honor are: the 2801 Huygens asteroid, and the 467 kilometer-wide Huygens crater situated in mars’ lapygia quadrangle.