Some interesting things you should know about concept of relativity

INTRODUCTION :

           When the experiments in search of the ether drift  failed , it began to be increasingly realised that there was no such thing as an absolute or privileged frame of reference and that the basic laws of physics took the same form in all inertial frames of reference . The implications of this Galilian invariance principal were emphasised by the French mathematical physicist . When he started that the laws of physical phenomena the same ,whether for an observer fixed or for an observer carried along in a uniform movement of translation , so that we have not and could not have any means of discerning whether or not we are carried along in such a motion .

 The Main Theory : 

This simply means that if we are drifting with uniform speed in a spaceship , with all the windows closed , we shall not be able to say , with the help of any experiments we might choose to perform , whether we are at rest or in a motion . If , however , we look out of a window ,, we shall be able to say merely that we are in motion with respect to the fixed stars but not whether we or the stars are actually in motion .

How near , indeed , had poincare thus come to expounding the theory of relativity and yet how far he actually was from it . For , instead of grasping the implications of the failure of all ether--drift experiments , and building up a new theory on its basis , discarding older nations of space and time , he concerned himself with trying to somehow save the old classical theory by suitable adjustments and modifications in it .

Thus , from the negative results of the ether--drift experiments and from his own reasoning , Einstein felt fully convinced that there was no such thing as an absolute or fixed frame of reference . He examine the physical consequences of the absence of such a frame of reference and had the boldness to break away from old and traditional concepts of space and time . He knit his conclusions and revolutionary ideas into a cogent theory which he announced to an unsuspecting world in the year 1905 as his SPECIAL THEORY OF RELATIVITY . And , ten years later , in 1915 , followed the second and the more complex and difficult part of it in the form of the  GENERAL THEORY OF RELATIVITY . The former deeals with problems associated with unaccelerated frames of reference , i.e. , those which move with uniform relative velocity with repect to one another and the latter with those associated with accelerated ones .

We shall concerns ourselves here mainly with only the Special theory of relativity which is not only comparatively simpler but has also produced the most profound effect on the entire field of physics .