Christiaan Huygens (April 14, 1629 – July 8, 1695) was a Dutch mathematician, astronomer and physicist; born in The Hague as the son of Constantijn Huygens, a friend of René Descartes. He studied law and mathematics at the University of Leiden and the College of Orange in Breda before turning to science. Historians commonly associate Huygens with the scientific revolution.
Huygens achieved note for his arguments that light consisted of waves, which became instrumental in the understanding of wave-particle duality. He generally receives credit for his role in the development of modern calculus and his original observations on sound perception (see Repetition Pitch). In 1655, he discovered Saturn‘s moon Titan. He also examined Saturn’s planetary rings, and in 1656 he discovered that those rings consisted of rocks. In the same year he observed and sketched the Orion Nebula. His drawing, the first such known of the Orion nebula, was published in Systema Saturnium in 1659. Using his modern telescope he succeeded in subdividing the nebula into different stars. (The brighter interior of the Orion Nebula bears the name of the Huygens Region in his honour.) He also discovered several interstellar nebulae and some double stars. Huygens formulated what is now known as the second law of motion of Isaac Newton in a quadratic form. Newton reformulated and generalized that law.
He also worked on the construction of accurate clocks, suitable for naval navigation. In 1658 he published a book on this topic called Horologium. In fact his invention on Christmas 1656, the pendulum clock (patented 1657), was a breakthrough in timekeeping. Devices known as escapements regulate the rate of a watch or clock, and the anchor escapement represented a major step in the development of accurate watches. Subsequent to this publication, Huygens discovered that the cycloid was an isochronous curve and, applied to pendulum clocks in the form of cycloidal cheeks guiding a flexible pendulum suspension, would ensure a regular (i.e isochronous) swing of the pendulum irrespective of its amplitude, i.e. irrespective of how it moved side to side. The mathematical and practical details of this finding were published in “Horologium Oscillatorium” of 1673. Huygens also observed that two pendulums mounted on the same beam will come to swing in perfectly opposite directions, an observation he referred to as odd sympathy which in modern times is known as resonance. Contrary to sometimes expressed popular belief Huygens was not a clockmaker, and is not known to have ever made any clock himself; he was a scholar, scientist and inventor, and the oldest known pendulum clocks were made “under the privilege” -i.e. based on a license from Huygens- by Salomon Coster in The Hague. The oldest known Huygens style pendulum clock is dated 1657 and can be seen at the Museum Boerhaave in Leiden, which also shows an important astronomical clock owned and used by Huygens.
Huygens also developed a balance spring clock more or less contemporaneously with, though separately from, Robert Hooke, and controversy over whose invention was the earlier persisted for centuries. In February 2006, a long-lost copy of Hooke’s handwritten notes from several decades’ Royal Society meetings was discovered in a cupboard in Hampshire, and the balance-spring controversy appears by evidence contained in those notes to be settled in favor of Hooke’s claim.
The Royal Society elected Huygens a member in 1663. In the year 1666 Huygens moved to Paris where he held a position at the French Academy of Sciences under the patronage of Louis XIV. Using the Paris Observatory (completed in 1672) he made further astronomical observations. In 1684 he published “Astroscopia Compendiaria” which presented his new aerial (tubeless) telescope.
Huygens speculated in detail about life on other planets. In his book Cosmotheoros, further entitled The celestial worlds discover’d: or, conjectures concerning the inhabitants, plants and productions of the worlds in the planets (see online edition) he imagined a universe brimming with life, much of it very similar to life on 17th century Earth. The liberal climate in the Netherlands of that time not only allowed but encouraged such speculation. In sharp contrast, philosopher Giordano Bruno, who also believed in many inhabited worlds, was burned at the stake by the Italian authorities for his beliefs in 1600.
In 1673, Huygens carried out experiments with internal combustion. Although he designed a basic form of internal combustion engine, fueled by gunpowder, he never successfully built one.
In 1675, Christiaan Huygens patented a pocket watch. He also invented numerous other devices, including a 31 tone to the octave keyboard instrument which made use of his discovery of 31 equal temperament.
Huygens moved back to The Hague in 1681 after suffering serious illness. He attempted to return to France in 1685 but the revocation of the Edict of Nantes precluded this move. Huygens died in The Hague on July 8, 1695.
(See Wikipedia for references)