The theory of the gravitational waves: the origin
In 1958, a 25 years old PhD student named Andrzej Trautman at the Physics Institute of Polish Academy of Science published a series of papers on his novel formalism for the gravitational radiation. This new framework is covariant and independent of any background spacetime geometry. Through these works, Trautman developed a concept of the energy of the gravitational radiation, and showed that the radiated energy is non-negative under proper asymptotic conditions. He calculated the expansion of the Riemann tensor, and discovered that it contains a radiative term equipped with the transversal tensor structure. When those results came to the attention of Felix A. E. Pirani, he invited Trautman to deliver a series of lectures at Department of Mathematics in King's College of London. These lectures from May to June of 1958 were attended by Pirani, Hermann Bondi and, remarkably, even by Peter Higgs!
Before Andrzej Trautman's work in the 1950ties and 60ties there was no understanding of the true nature of gravitational waves. Most of the experts in the field, including Einstein himself, supposed that the gravitational waves were a coordinate artifact: some physicists even (incorrectly) "proved" that these waves carry no energy. The mood changed due to Trautman's brilliant demonstration that material sources that emit gravitational waves loose energy and this energy is carried by the waves to infinity. Trautman also gave (with Robinson) an exact solution to Einstein's field equations that described a spherical gravitational wave. These results laid the foundation for all further developments of the gravitational wave theory made by Pirani, Bondi, Sachs and many others.
Andrzej Trautman defended his PhD in 1959 in Warsaw. Currently he is a distinguished member of Chair of the Theory of General Relativity and Gravitation at Faculty of Physics of the University of Warsaw. Recently, the gravitational waves predicted by Einstein and firmly established as a real phenomenon by Trautman have been finally detected.