The general Theory of relativity or general relativity is a theory of the field gravitatiorio and the general systems of refrencia, published by Albert Einstein in 1915 and 1916. The name of the theory must to that it generalizes the call theory special theory of relativity.
The introduced fundamental principles in this generalization are the Principle of equivalence, that describes to the acceleration and the gravity like aspects different from the same reality, the notion of the curvature of the space-time and the generalized principle of covariancia.
The basic intuition of Einstein was to postulate that in a concrete point it is not possible to be distinguished experimentally between a body accelerated uniformly and a gravitational field uniform. The general theory of relativity allowed to also found the field of cosmology.
Main characteristics the essential characteristics of the general theory of relativity are the following ones: The general principle of covariancia: the laws of the physics must take the same form in all the systems from coordinates. The inertial free movement of a particle in a gravitational field is made through geodesic trajectories. The principle of equivalence or local invariancia of Lorentz: the laws of special relativity are applied locally for all the inertial observers.
Principle of covariancia
The covariancia principle is one of the main motivations that took to Einstein to generalize the theory of special relativity. This principle affirms that, the fundamental laws of the physics must whatever have the same form for any observer the state of movement of this one.
The objectivity of the material world requires that the measures done by diverse observers are relacionables by means of fixed laws of transformation: Mathematically the covariancia principle implied that the laws of the physics must be tensoriales laws in which the magnitudes measured by different observers are relacionables according to the transformation of coordinates of each observer. The covariancia principle physically depended on the observation on which it stops diverse classes systems of reference coordinates did not exist physical procedure to distinguish among them.
Influenced by the principle of equivalence and other observations Einstein and others they got to theorize that it was possible to construct a theory where all the equations could be written in a sufficiently general form as to have the same form in any system of coordinates. Thus the apparent distinction between inertial and noninertial systems of the Newtonian mechanics was false, since these are not more than systems in which the symbols of Christoffel which they appear in the previous expression annul, and therefore, the inertial systems are only a particular case of reference system, but not a privileged or none outstanding type of reference system, a time the laws are formulated in the suitable covariant form.
