|Christian Huygens (1629 - 1695)|
Christian Huygens was a Dutch physicist, mathematician, astronomer, and inventor who was the leading proponent of the wave theory of light. He also made important contributions to mechanics, stating that in a collision between bodies, neither loses nor gains "motion'' (his term for momentum). In astronomy, he discovered Titan (Saturn's largest moon) and was the first to correctly identify the observed elongation of Saturn as the presence of Saturn's rings.
Christian Huygens was born at the Hague on April 14, 1629, and died there on July 8, 1695. He generally wrote his name as Christiaan Hugens, and it is also sometimes written as Huyghens.
Pendulum Clock and Watches
Around 1675, Huygens developed the balance wheel and spring assembly, still found in some of today's wrist watches. This improvement allowed 17th century watches to keep time to 10 minutes a day. Watches or portable clocks had been invented early in the sixteenth century, however, they were clumsy and unreliable, being driven by a main spring and regulated by a conical pulley and verge escapement. The first watch whose motion was regulated by a balance spring was made in Paris under Huygens' directions, which he gave as a gift to Louis XIV the King of France.
In 1689, he traveled to England in order to meet with Isaac Newton, whose Principia had been published in 1687. Christian Huygens fully recognized the intellectual merits of the work, however, he thought that Newton's theory was incomplete because it did not explain gravitation by any mechanical means.
In 1690, Christian Huygens published his treatise on light in which the undulatory theory was expounded and explained. The general idea of the theory had been suggested by Robert Hooke in 1664, however, not in great detail. Up to that point in time, only three theories have been suggested about the mechanics of light.
According to this last theory space is filled with an extremely rare ether, and light is caused by a series of waves or vibrations in this ether, which are set in motion by the pulsations of the luminous body. From this third theory, Christian Huygens deduced the laws of reflection and refraction, explained the phenomenon of double refraction, and gave a construction for the extraordinary ray in biaxial crystals; while he found by experiment the chief phenomena of polarization.
Before he died Christian Huygens wrote "Cosmotheoros, or Conjectures Concerning the Planetary Worlds", a non-fictional premise on life on other planets.
with > Telescopes
This principle, stated by Dutch physicist Christian Huygens (1629-95), is extremely useful in understanding effects due to refraction, reflection, diffraction, and scattering of all types of radiation, including sonic radiation as well as electromagnetic radiation and applying even to ocean-wave propagation.