Theory of Relativity for the layman

Sapeshathavadaya
Author: G. W. Nandisena
Godage Publishers
Reviewed by R. S. Karunaratne

G. W. Nandisena's latest book Sapeshathavadaya is the authentic Sinhala translation of James A Coleman's path-breaking work Relativity for the Layman.

It was way back in 1915 that the eminent physicist Albert Einstein developed the Theory of Relativity. He considered that objects accelerated with respect to one another. He had to develop the Theory of Relativity as there was an apparent conflict between the laws of relativity and the law of gravity. Einstein's theory was based on the principle of equivalence which holds that forces produced by gravity are in every way equivalent to forces produced by acceleration. He found that it was impossible to distinguish between gravitational and accelerational forces through experiments.

He said that a man in a closed car going down a rail track could not say whether he was at rest or in motion. According to his theory, if the car were speeded up or slowed down, the occupant could not tell whether the forces so produced were due to gravitation or acceleration.

Astronaut

Explaining his theory further, Einstein said that an astronaut in a stationary rocket would have his feet pressed against the floor of the rocket. When the rocket is in outer space the astronaut's feet are again pressed against the floor. He will not know whether he is at rest or moving in outer space.

Einstein said that Newton's Law of Gravitation was an unnecessary hypothesis. He attributed all forces, to acceleration. However, the Theory of Relativity has undergone much development at the hands of Einstein himself and other scientists. Much of the latest work on relativity was developed to create a workable realistic quantum mechanics. In recent years the British physicist Steven Hawking attempted to integrate quantum mechanics with relativity theory.

Complicated theory

All these developments may baffle the layman. James A. Coleman's Relativity for the Layman has explained the Theory of Relativity in the layman's language. Probably G. W. Nandisena was the first writer to translate the book into Sinhala. By doing so he has introduced a complicated scientific theory to Sinhala readers.

In a book running into nearly 150 pages, Nandisena has dealt with the speed of sound and light, the great dilemma, the difference between the reasonable theory of relativity and the special theory of relativity, results of scientific experiments, Theory of Relativity and the nature of the universe.

Nandisena's attempt to introduce the complex subject of Theory of Relativity to the layman is praiseworthy. The value of the book would have been enhanced if he had included a contents' page and a glossary of scientific terms.