Mach's principle

The Mach principle is named after Ernst Mach physical principle for the type of room. It contradicts the Newtonian conception of absolute space. After the Mach's principle, one can not speak of a relative motion of a body on an absolute space, but only by movements in relation to all the other bodies of the universe. The general theory of relativity is based on this principle, according to which the nature of the area is determined only by the in his matter and energy.

In the literature a number of different versions of the Mach 's principle is given, which differ substantially in some cases.

Historical context and counter- concepts

Although named after Ernst Mach, the core idea of the principle, the rejection of absolute space has been represented as an independent entity or the acceptance of the body as the only actually existing physical entities long before Mach. For example, advocated Leibniz or much earlier Aristotle similar ideas. In contrast, the alternative notion in the absolute space and the bodies are their own entities already represented by Democritus. The third direction of the view can be distinguished, which starts from the sole existence of space and the physical body will not perceive it as a stand-alone entities, but ultimately this will reduce to geometrical properties of space.

Because of the difficult precisely be formulated core statement of Mach 's principle, there are now a variety of versions and different concrete formulations of Mach 's principle, which are not equivalent to each other.

Newton's bucket experiment and Mach's criticism

Especially Newton took the existence of absolute space and an absolute time and established them in his Philosophiae Naturalis Principia Mathematica with the bucket experiment. One can therefore always prove whether the water revolves in a bucket about its rotational axis relative to an absolute space, since in this case the surface of the water fancy a paraboloid of revolution, whether the bucket itself mitdrehe or not.

Mach's objection to this thought experiment is that Newton did not consider the influence of the remaining matter of the universe on the water. Newton's experiment would only be in an otherwise empty universe of meaning. In the real universe, in which matter is present, either instead of a rotation relative to an absolute space, as claimed by Newton, only a rotation relative to the other celestial bodies for the experiment of importance:

For example, therefore, remain the centrifugal force at the orbital motion of the Earth around the Sun the same when earth and sun rested and rotated the masses of the universe to the Sun-Earth system.

Mach's Principle and the General Theory of Relativity

The principle was named by Albert Einstein in 1918 by Ernst Mach, who had represented it in his book The mechanics in their development. The Mach principle motivated and led Einstein in the development of the general theory of relativity. However, they later turned out to be incompatible with some concrete formulations of Mach's principle. It is questionable whether other formulations of Mach 's principle with the theory of relativity are compatible.