Prerequisites for the creation of the theory of relativity of a. Einstein

An important role in creating a scientific picture of the world was played by the principle of relativity of one of the founders of modern natural science of Galileo - the principle of equality of all inertial reference systems in classical mechanics, which states that no mechanical experiments used in any inertial frame of reference can be recognized by any system of reference. or moves evenly and in a straight line.

Mathematically, the principle of Galileo's relativity expresses the invariance of the equations of mechanics with respect to the transformations of the coordinates of moving points (and time) in the transition from one inertial frame of reference to another - Galilean transformations.

For the first time, the position on the relativity of mechanical motion was expressed by Galileo Galilei in 1638 in his work "Dialogue on the two major systems of the world - Ptolemy and Copernicus." Ibid one of the fundamental principles of physics - the principle of relativity. Galileo used a visual and imaginative method of presentation. He wrote that being "in the room below the deck of a ship" and conducting experiments and observations on everything that happens there can not determine whether the ship is resting, or whether it moves "without shocks", that is, evenly and straightforwardly. At the same time, two points were made, which are the essence of the principle of relativity:

1) movement in relation to: in relation to the observer "indoors" and to the person watching from the shore, the movement looks different;

2) the physical laws governing the movement of bodies in this room are independent of the movement of the ship (unless this movement is uniform). In other words, no experiments in a "closed cabin" allow you to determine whether the cabin is resting or moving in a uniform and straight line.

Thus, Galileo concluded that mechanical motion is relative, and the laws that define it are absolute, that is, irrelevant. These provisions were fundamentally different from Aristotle's generally accepted ideas of the existence of "absolute peace" and "absolute motion" at that time.

The principle of Galileo's relativity is organically incorporated into the classical mechanics created by I. Newton. It is based on three "axioms" - three of Newton's famous law. Already the first of them, which states: "Every body continues to remain in its state of rest or uniform and rectilinear motion, as long as it is not forced by the applied forces to change this state," speaks of the relativity of motion and at the same time indicates the existence of frames of reference (they were called inertia), in which bodies that do not experience external influences move "inertia" without accelerating or slowing down. Such inertial systems are also implicit in the formulation of the other two Newton laws. As we move from one inertial system to another, many quantities that characterize the motion of bodies, such as their velocities or forms of trajectory, change, but the laws of motion, that is, the relations that bind these quantities, remain constant.

To describe mechanical movements, that is, to change the position of bodies in space, Newton clearly formulated an idea of ​​space and time. Space was thought of as some kind of "background" on which the movement of material points unfolds. Their position can be determined, for example, by Cartesian coordinates x, y, z, which depend on time t. When moving from one inertial frame of reference K to another, K 'moving with respect to the first along the x-axis with velocity v, the coordinates are transformed: x' = x - v × t, y '= y, z' = z, and time remains unchanged: t '= t. Thus it is assumed that time is absolute. These formulas are called Galileo's transformations.