Introduction to Light
Light of Class 8
PIERRE GASSENDI (1592–1655)
Pierre Gassendi (1592–1655), an atomist proposed a particle theory of light which was published posthumously in the 1660s. Isaac Newton studied Gassendi's work at an early age, and preferred his view to Descartes' theory of the plenum.
One of Newton's arguments against the wave nature of light was that waves were known to bend around obstacles, while light travelled only in straight lines.
Newton's theory could be used to predict the reflection of light, but could only explain refraction by incorrectly assuming that light accelerated upon entering a denser medium because the gravitational pull was greater.
Newton published the final version of his theory in his Optics of 1704. His reputation helped the particle theory of light to hold sway during the 18th century. The particle theory of light led Laplace to argue that a body could be so massive that light could not escape from it. In other words it would become what is now called a black hole. Laplace withdrew his suggestion later, after a wave theory of light became firmly established as the model for light (as has been explained, neither a particle or wave theory is fully correct).