The Enigma Of The Universe : Ether and Wave Theory of Light

After the adoption of Newton's theory of absolute space in the field of physics, the physicists of the 18th and 19th centuries tried to solve several difficulties that had arisen in the course of development of classical physics, One of them was the phenomenon of light. On the basis of experiments, the undulatory nature of light was confirmed, and consequently, the wave theoryof light was accepted-light was thought to be propagated in the form of waves. But the question which perplexed the scientist's minds was: just as water propagates the waves of the sea and air transmits the vibrations we call sound, which is the medium for propagating the light-waves? Further, when the experiments had shown that light can travel in vacuum, the scientists conceived of a hypothetical medium, which they termed as "ether". They assumed that this substance ether must pervade all space and matter. They also endowed ether with certain mechanical properties such as elasticity and thus regarded it as a kind of physical substance. Later on, Faraday propounded another kind of ether as the carrier of electric and magnetic forces. When Maxwell finally identified light as an electromagnetic radiation, the case for the ether, as a medium of propagation, seemed to be assured.^[1] Thus, the final conclusion of the Newtonian physics was that the space of the universe was pervaded by an invisible medium (ether) through which the stars and planets made their motion and light travelled in the form of waves. This theory of the universe provided a mechanical model for all known phenomena of nature and it provided the fixed frame of reference, the absolute and immovable space, which Newton's cosmology required.^[2]