The space of Einstein

In the time of Newton, physicists imagined the world space as a huge "container" filled with various celestial bodies, between which there are forces of mutual attraction that have nothing to do with the properties of space itself. This understanding of space was only the first approach to truth. A deeper understanding of the structure of the universe and the intrinsic nature of gravitation was presented by Albert Einstein in his so-called general theory of relativity. The space of Einstein was declared inextricably linked with the properties of matter.

The space of Einstein was declared inextricably linked with the properties of matter

However, the first step towards a deeper understanding of space was made by the great mathematician N.I. Lobachevsky, who showed that the geometry of the world around us may not be as simple and obvious as it seemed before.

As is known, N.I. Lobachevsky was interested in the fifth postulate of the geometry of Euclid, that is, the geometry of the world in which we live. The fifth postulate states that through a point located outside a straight line one can draw only one straight line parallel to this one. This statement, consistent with our daily experience, for a long time was considered quite obvious and did not cause any doubt. Lobachevsky decided to test his justice. He set himself the goal of constructing a geometry whose initial positions would be identical in all respects to the usual ones, but in which Euclid's assertion of parallel lines would not take place. Without changing anything in "ordinary", Euclidean geometry, the scientist took as its starting point all of its basic axioms, but added a new fifth postulate to them. He suggested that through a point lying outside a straight line, you can draw as many lines as are parallel to it.

N.I. Lobachevsky reasoned thus: if such an assumption is incorrect, it inevitably leads to a contradiction, and Euclid's assertion of parallel lines will thereby be proved. The scientist began to build a new geometry, at every step expecting to meet the desired contradiction. But it somehow did not arise. In the end, Lobachevsky realized that there will be no contradiction and that it is possible to build a completely consistent geometry without Euclid's approval of parallel lines.

It was a truly brilliant idea. If Euclidean geometry is not the only possible geometric system, then it is likely that the geometric properties of the universe can go beyond the framework of this system...

The space of Einstein was the next step of humanity in understanding the structure of the universe and the intrinsic nature of gravity. Einstein came to the conclusion that gravitational forces are directly related to the physical properties of space itself. It turned out that any body does not simply exist in space in itself, but changes its geometry around itself. The space is curved and the light ray in it will spread no longer in a straight line, but along a curved line. But how to test this experience? It goes without saying that it is almost impossible to carry out such an experiment under laboratory conditions. After all, in order for the deviation of the light beam to be sufficiently noticeable, it is necessary to act on it with an extremely large gravitating mass.

Fortunately, such an experiment is "put" by nature itself. Due to the rotation of the Earth around the Sun, the observer sees that our daylight moves against the backdrop of more distant stars. Because of this, one or another star appears in the sky near the edge of the solar disk and its light rays on the way to the Earth pass next to the Sun. If the curvature of space near the sun does take place, then the light beam must deviate from the straight line. Then for the observer on earth, the star will move somewhat relative to its usual position in the sky. This deviation of the light rays as a result of the curvature of Einstein's space is fully confirmed by studies based on the idea that in the role of the cosmic object sending rays, and in the role of the deflecting "body", whole galaxies should act.

Imagine that two galaxies are located approximately along the line of sight. If the properties of Einstein's space are correct in galactic scales, then the light rays of the farther galaxy, passing "next" to the nearer, should experience a certain curvature. As a result, we will see the distant galaxy in a somewhat distorted form, which was confirmed by multiple studies.

Thus, the property of the Einstein space to be bent in the region of large masses can be considered proven for metagalactic scales. In everyday life, we almost do not feel this, because we usually have to deal with relatively small distances. However, in the transition to cosmic scales, the curvature of space becomes essential.