p These philosophical concepts of space and time as universal forms of the existence of matter should be distinguished from the concepts about the space and time properties of concrete material objects accepted in natural science.

p As science develops these concepts too are developed and specified, new properties of space and time are discovered and the dependence of these properties on the material nature of bodies is more definitely established.

p Classical mechanics, recognising the objectivity of space and time, separated them from matter, and held them to be absolutely uniform and immutable. Isaac Newton (1643-1727), the founder of classical mechanics, for example, pictured space as a huge receptacle in which things were placed in a definite order, but these things themselves supposedly had no relation to space whatsoever.

p Newton held that spatial properties of all bodies of the Universe are similar and fully covered by Euclidean geometry which is taught at school and which he regarded as the only possible, the absolute geometry.

p His views of time were similarly metaphysical.

p The great Russian mathematician Nikolai Lobachevsky (1792-1856) elaborated a new, non-Euclidean geometry, which refuted the metaphysical views of space and extended man’s ideas of the spatial properties of bodies. Lobachevsky arrived at the conclusion that the properties of space are not 55 identical in different regions of the Universe, that they depend on the nature of physical bodies and on the material processes taking place in them. Convinced that in nature there are bodies whose spatial properties do not fit into the framework of Euclidean geometry, he discovered these new properties, demonstrating specifically that on definite surfaces the sum of angles of a triangle is not equal to 180°, as in Euclidean geometry, but is smaller.

p The theory of relativity, elaborated by Albert Einstein (1879-1955), one of the greatest physicists of all time, is the modern theory of space and time in natural science. This theory reveals the organic connection of space and time both with each other and with matter in motion.

p The special theory of relativity demonstrates the dependence of space and time properties of bodies on the velocity of their movement. At relatively small velocities it is impossible to trace this dependence because the space and time, properties change on a scale which can be practically detected only at speeds close to that of light.

p The theory of relativity shows that at speeds close to that of light the length of a moving body compared to a body in a state of rest decreases as the speed increases. Moreover, time too does not remain invariable: with the increase in speed the course of time is slowed down. These conclusions, which follow from the theory of relativity, have been corroborated experimentally. For example, the life of the meson (an elementary particle which arises during the fission of an atomic nucleus) is very short, but if its speed is increased, the “lifetime” of the meson is lengthened.

p According to the theory of relativity, space and time change not by themselves but in inseparable interconnection. This connection is so firm that they form an unbreakable whole and time acquires, as it were, the role of a fourth dimension, in addition to the three dimensions of space. The theory of relativity also gives a strictly mathematical expression to the organic connection of space and time.

p The general theory of relativity or the theory of gravitation, has demonstrated that the properties of space and time also depend on the presence of masses of matter. Bodies possessing a huge mass and great force of gravity produce a change in the properties of space near them; as physicists 56 say, space “is curved”. Time too changes correspondingly: it slows down.

p At first glance, the conclusions of the theory of relativity seem to run counter to our customary notions about the properties of space and time. But they are true and are confirmed by scientific experiments. Their unusual character merely goes to show that in knowledge man must not confine himself to customary notions, but must go farther and deeper, and reveal the entire complexity and diversity of the material world.

We have seen that the concepts about the properties of space and time, given by natural science, undergo change. But this changeability does not in any way challenge the propositions of dialectical materialism concerning their objective existence. On the contrary, each success of science furnishes more and more proof of the objectivity of space and time, and their inseparable connection with matter in motion.