SPECIAL THEORY OF RELATIVITY

This book is a very comprehensive treatment of the Special Theory of Relativity with all advanced topics treated well. Also interesting is the article by V. L. Ginzburg (whose book Key Problems of Physics and Astrophysics we saw recently) which is  Who Developed Special theory of relativity and how? This may be of special importance to those who wish to know historical roots of development of relativity.

It is in this book that I first read about the superluminal speeds which are possible and are indeed result of STR. Section 8.1 deals with these phenomena and there are 5 of them discussed here. These are for real and are indeed observed in nature. For example the hot-spot in case of radio jets appeared to move at faster-than-speed-of-light. The easiest one which you can indeed do is to take a torch and make a spot on the wall, there is no limit on how fast the spot can travel. Let us see what Ugarov has to say on this topic:

Let us place a searchlight at the origin of coordinates and start rotating it at the angular velocity . Let us circumscribe a stationary sphere of radius  around the origin. Then the light spot will run along the surface of this sphere at the linear velocity . This velocity can exceed the velocity of light. The example of such a beam is provided by a rotating pulsar. The light spot of the Crab Nebula pulsar runs along the Earth surface at the velocity equal approximately to . But as in the previous cases no signal is transmitted at such a velocity. As a matter of fact, every point of a screen (the Earth) receives a new portion of light energy from a searchlight (pulsar), but not from a neighbouring point of the screen. Therefore, it is impossible to transmit information from one point of the screen to another.

The 4-forms, electrodynamics, transformations are discussed with substantial emphasis on the physical meaning. These kind of discussions make this book a wonderful resource to learn.