by professor Vladimir BRAGINSKY, Dr. Sc. (Phys. & Math.), Head of the Radiophysical Department at the Physical Faculty of Moscow State University chairman of the Commission on Gravitation at the USSR Academy of Sciences People have long come to know the physical meaning of the word "field". As a matter of fact, we live in the midst of and are influenced by all kinds of fields (nuclear, magnetic, electrical). Beyond any doubt, the most significant and palpable one is that of gravity. Whereas the other fields affect either specific materials or certain properties of materials or certain properties of matter, the gravitational field is of a universal nature, an indispensable component of life. But for gravity, there would be no bonds between matter, not only on Earth, but also in the entire Universe. And yet though the gravitational field is all-pervading and vital to nature and man, we know much less about it than, say, about the electromagnetic field discovered and thoroughly investigated not so long ago. Why is this so? Electromagnetic waves are a very opportune and readily controlled manifestation of the electromagnetic field, which makes it easy to probe into its nature. Is it possible to explore the gravitational field in a similar manner? Do gravitational waves really exist? If so, why have they not been detected earlier? In the USSR three laboratories- of Moscow State University, the Academy's Institute of Earth Physics and the Institute of Crystallography-are jointly developing aerials to detect bursts of gravitational radiation from extraterrestrial sources. Their existence was predicted by the great Einstein at the beginning of the century. He held, however, that they are extremely feeble and weakly interact with matter-the reason for their having escaped detection. According to present-day concepts based on the theory of relativity, they are disturbances of the gravitational field travelling with a finite velocity in space and carrying energy in muc ... Читать далее