PART 2 : Main ideas of General Relativity




In this subdirectory the brief introduction to Special and General Relativity is presented. Here I describe the main ideas of Special and General Relativity with simple physical explanation. Let list the main ideas of General Relativity and the main difference of Newtonian gravity from the General Relativity (GR below).

The space - time in GR is curved.
The main object in GR is metric.
The metric coefficient determine the property of space - time and the property of gravitational field.
The gravitational field in Newtonian physics is determined by the one scalar value which is gravitational potential.
In GR the gravitational field is 10 function which are metric coefficients. The metric of space -time determines both
geometry of space and time and properties of gravitational field.
The law of motion in cosmology (for instance, the light ray law) is the motion laws on the curved nonstationary background.
The source of gravitational field in Newtonian gravity is mass. This is no longer valid in GR. The source of gravitational field in GR is stress - energy tensor which has 10 independent component. It provides more complex behaviour of gravitational field in GR.
In particular conditions gravitational attraction can trasforms into gravitational repulsion. In the modern cosmology these conditions are called the negative pressure or false vacuum conditions.