Pre-text Exercises. 1. Before reading the text, read the following questions

1. Before reading the text, read the following questions. Do you know the answers already? Discuss them briefly with other students to see if they know the answers. The questions will help to give a purpose to your reading:

– Do you know that there exist many theories of gravitation sometimes flatly contradicting one another?

– Why is it important to understand processes in a microcosm?

– Do you know which equations are used to compute the gravitational field of space objects?

2. Learn to recognize international words:

universal, gravitation, traditional, curvature, phenomenon, cosmic, existence, process, microcosm, quantum, sensation, characterize, discussion, conference, symposium, idea, elementary, general, experiment, astrophysicist, computer, object, fundamental, problem, energy, academician, determine, homogeneous, attraction, condition, physical, electromagnetic, method, antagonistic, element, galaxy, evolution, mass.

Read and translate the text:

The World of Hypotheses. Was Einstein Right?

The universal law of gravitation is claiming more and more attention from scientists. When Newton described gravitation for the first time, he gave sci­ence the law of universal gravitation. Einstein "exploded" traditional classi­cal notions about it, linking gravitation with the curvature of space with his general theory of relativity. In both cases gravitation was seen as a phenom­enon of a cosmic scale, since gravitational fields are "perceptible" only with the existence of huge masses. Now scientists hope that it may provide a key to understanding processes in a microcosm, at the quantum level. It is at the junction of quantum and gravitational ideas that science can expect to make the most sensational discoveries. This expectation characterized gravitationalists' discussions at the 6th All-Union Gravitational Conference and at symposiums in Moscow and Leningrad (1984). What ideas do scientists have who are trying to connect the gravitational processes of the universe with the world of elementary particles?

The general theory of relativity, which is being brilliantly confirmed by experiments, the equations of which are used by astrophysicists to compute the gravitational fields of space objects, possesses fundamental difficulties which are not clarified to this day. The chief one is the problem of deter­mining the energy of the gravitational field. In the framework of Einstein's theory this question remains a veritable "headache" for scientists. Opinions on how exactly to compute this energy invariably differ. Recently Academician A. Logunov and Professor M. Mestvirishvili advanced a new theory of gravitation, in which the energy of the gravitational field can always be determined. Unlike Einstein, Logunov and Mestvirishvili main­tain that our world is homogeneous, while gravitational attractions in it are conditioned not by the curvature of space but by some physical force field like the electromagnetic field. They draw on the methods used in the field theory of elementary particles.

What is to be done with the equations of the general theory of relativity which faithfully serve science? Are they not in antagonistic contradiction with Logunov and Mestvirishvili's theory? In fact, they are not. They are perfectly consistent with it if another four equations are added. Moreover, the curvature of space, which is the main element for Einstein, plays only a secondary part in the new theory. It is interesting to note that all the experiments, which hitherto corroborated the general theory of relativity, also con­firm Logunov and Mestvirishvili's theory.

So, what does the universe look like according to the new theory? Einstein's theory allows for the existence of different models of the universe – "open", "closed", etc. – but Logunov and Mestvirishvili allow for only one model. Their universe can only be "flat". This, in turn, presupposes the existence in it of some concealed, unobservable mass. Surpassing the mass of all galaxies taken together many times over, this invisible mass ensures the evolution of the universe as a flat world. As often happens with new theories, Logunov and Mestvirishvili's theory is hostilely being received by many gravitationalists. However, it is mathematically correct, not open to doubt. Nor is it at variance with known experimental data. To solve the question of which is correct – Einstein's general theory of relativity or the theory advanced by Logunov and Mestvirishvili – there will have to be more exper­iments.