title: What Is Relativity?: An Intuitive Introduction to Einstein's Ideas, and Why They Matter
author: Jeffrey Bennett
description: *Starred Review* Doubtful in 1919 that even three scientists fully understood Einsteins theory of relativity, the astrophysicist Arthur Eddington would marvel at this book. For in its relatively few pages, Bennett explains relativity to ordinary readers. Applying two simple principlesthe uniformity of natural law and the invariance of the speed of lightreaders conduct thought experiments that fuse time and space into a single concept. Armed with this concept, readers see why time slows down for space-travelers streaking across the cosmos, their spaceship growing more massive but shorter. Similarly, as they plunge into a black hole, doomed but enlightened readers can at least congratulate themselves on comprehending how extreme gravitation creates inescapably lethal tidal forces. Still, a perplexing mystery remains. Why does the singularity at the center of a black hole look irreconcilably different when viewed through quantum physics than it does when viewed through relativity? Undaunted, Bennett views this conundrum as the stimulus for scientific progress that will resolve it. Indeed, in the very fact that one man could formulate a theory as powerful as relativity, Bennett sees reason to hope that the entire human species can ultimately conquer stubborn nonscientific problemssocial, political, even metaphysical. An impressively accessible distillation of epoch-making science. --Bryce Christensen
zlib_text: The teaching of Relativity
  "Relativity teaches us the connection between the different descriptions of one and the 
  same reality".
  The formulation of Relativity
  "I sometimes ask myself how it came about that I was the one to develop the theory of 
  relativity. 
  The reason, I think, is that a normal adult never stops to think about problems of space 
  and time. 
  These are things which he has thought about as a child. 
  But my intellectual development was retarded,as a result of which I began to wonder 
  about space and time only when I had already grown up".
  On the Moon being there without Looking at It ...
  "I think that a particle must have a separate reality independent of the measurements. 
  That is an electron has spin, location and so forth even when it is not being measured. 
  I like to think that the moon is there even if I am not looking at it.".
  Intelligence and the ultimate & fundamental ends
  "Intelligence makes clear to us the interrelationship of means and ends. 
  But mere thinking