Frame of reference is the beginning of the emergence of the theory of Relativity. The theory developed by Albert Einstein was a result of his analysis of physical phenomena that have never discussed the existence of a universal reference frame. Frame of reference that is used there are two types, namely inert frame of reference and terms of reference are not inert.
Frame of reference is not inert shells intended to accelerate. This reference frame used in the general theory of Relativity.
Inert reference frame is a coordinate system relative to the physical measurements (e.g. mass, velocity, time, length, energy, momentum and so on). A universal reference frame is a system that moves with the speed and direction are fixed (without acceleration).
Einstein's General Relativity Theory requires a curved space to describe the physical world is using mathematical theory of differential geometry and tensors to describe gravity and quite complicated. This theory has the same form for all observers, both for the observer who is engaged in an inert or frame of reference for the observer who is engaged in an accelerated frame of reference. In general Relativity, gravity is no longer a force (as in Newton's law of gravity) but is a consequence of the curvature of space-time. General relativity showed that the curvature of space-time is due to the presence of mass.
In this paper a general theory of Relativity is not discussed further. To be discussed is the special Relativity and relativistic dynamics.
For Further Explanations, you may download the DOC and PPT file
Click here to download The Theory of Relativity.doc file
Click here to download The Theory of Relativity.ppt file