Customer Reviews

It's About Time: Understanding Einstein's Relativity

5 star:		(8)
4 star:		(1)
3 star:		(1)
2 star:		(0)
1 star:		(0)

 

 

The basic ideas making up Albert Einstein's special theory of relativity are relatively easy to understand. The only mathematics required to understand the formulas is basic algebra and very little knowledge of physics is needed. The only essential physics background is an understanding of many of the words of physics. Concepts such as linear momentum, electromagnetic radiation, computing with units, velocity and simultaneity must all be clearly understood before you read this book.

Once into it, you will find some of the best non-technical descriptions of the special theory of relativity that have ever been published. While the author does not pathologically shrink from using equations, he also does not become infatuated with them. There are just enough to demonstrate the concepts and none that I considered superfluous. Many diagrams are used to illustrate the ideas and equations and the text is a superb complement to the formulas and figures.

The world where the special theory of relativity is valid is a strange one where our intuitive ideas based on everyday phenomena no longer apply. However, it is not impossible to understand and this book is the best place to begin that process.

One hundred years after Einstein published the theory of relativity, publishers are still promoting popular books that explain reltivity to the lay reader. This is the best such book that I have read. That's because Mermin's approach is to help the reder to develop a thinking style so that it becomes almost second nature to get your brain to hop between moving frames of reference. Mermin's thought experiments examine the outcome of experiments performed on moving trains or by moving rockets. The reader discovers the trick of examining the outcome from two points of view: inside the moving train, and outside watching the train go by. Almost everyone, including professers of physics, will benefit from a careful rreading of this book. It does include many equations and diagrams.

This book was produced from the lectures given for many years by the author for a course on Relativity that was given to Cornell University non-science majors. Aimed at an audience of non-scientists one would expect a watered-down, simplified book. While only basic algebra is utilized, with the introduction of almost no Physics, this is far from a watered-down or simple book. As the author clearly states, this in not a book that can be read like a novel. It requires deep concentration and a lot of patience to follow what is presented, but in the end the reader is rewarded for their efforts with a deeper understanding of what the Einstein's Theory of Relativity is all about- it's all about time. I have previously read the general treatments of relativity written by Einstein, Martin Gardner, Richard Wolfson, David Bohm, Max Born and the sections on relativity in Richard Feynman's physics text. Even with a considerable background I found a new understanding of the subject.

Unlike most relativity books, this one does not start with the reason's why Einstein developed a new way of looking at time and space and in doing so overturned Newton's ideas of time and space. The book focuses on the problem of examining events from different frames of reference, and in doing so develops the ideas of relativity without any detailed physics arguments, beyond the idea that the speed of light is the same for all observers, regardless of their velocity. The arguments are all logical and geometrical. Gradually one learns how events may or may not be simultaneous when viewed in the same or different frames of reference, how velocities combine, how time measured on a clock can be a function of the velocity at which the clock moves and how this leads to new concepts of space and time - to space-time. While relatively straight forward at first, the text got much more complex as it progressed and became so complex that after a while I found myself longing for the simplification of a bit more complex mathematics. In fact, it drove home to me how much mathematics can simplify a problem and how difficult things can get when one tries to do without it.

I found the first half of the book to be somewhat challenging, but in the end quite understandable. Unfortunately, I found the next third of the book to be much less clear. This portion of the book deals with the analysis of a "train of rockets" and the idea of space-time. Instead of dealing with the standard approach to space-time, Professor Mermin utilizes his own approach using the ideas of equiloc and equitemp, that he developed. I found this approach far more difficult to grasp than the conventional one. While it does bring out many features of space-time, it requires a difficult exercise in visualization, and in the end is used to only derive equations that had previously been derived in other, and in my opinion, much more assessable ways. I am sure that in Professor Memin's classes he assign's homework problems and discusses their solutions and in this way helps the student more firmly grasp the equiloc/equitemp concepts and how they are used. Studying this approach without them is, in my opinion, very difficult and a bit frustrating. One hopes that these might be included in future editions, or at least this section should be enlarged. The last sixth of the book deals with energy and mass, general relativity and why relativity may be as it is. I particularly liked the energy/mass chapter as it presents the subject in a modern manner, as opposed to the other books that I have read that follow Einstein's approach. This new approach utilizes the concept of mass being invariant in all frames of reference, so it is not a function of its velocity. Instead the analysis is done in terms of relativistic momentum.

Given that I liked this book and learned a lot from it, why am I giving it only four stars, instead of five? This is definitely not a book for someone who just wants to understand a bit about Relativity. For them I would recommend Gardner's book (Relativity Simply Explained) or the one by Wolfson (Simply Einstein). I would, however, recommend this book to someone, like myself, who has a reasonable general background in Relativity but is not studying the subject in a college course, with the understanding that this is a difficult book. I think that the book is best suited for a physics major studying relativity from another text. Physics professors who teach relativity will probably also like this book. I am thus giving the book only four stars because I do not think that it is a good choice for the stated target audience and I would like to be a slight counterweight to some of the five-star reviews that recommend this book without any reservations.

The book is as simple as it can be but not simpler. It is as if Einstein learnt to explain in english. It cleared my way of thinking about time-place events. Now I am just afraid to think how many such simple things can be out there which my mind has not yet ever analysed.

I really enjoyed this book on Relativity by Mermin. He shows you how relativistic effects like time dilation, length contraction, relativistic addition of velocities all follow from the fact that simulationeous events in one frame of reference are not simultaneous in another (relativistic simultaneity, of course, follows from the postulates of relativiy.) Unlike other books on this subject, he always shows the readers how events look in different frames of reference and how an observer in a particular frame explains the other observer's observations. Everything is always logically explained and he shows you how things are always consistent. In the last chapter he talks about whether things like length contraction or time dilation are "real" or just apparent effects. The one area I felt was not as clear was his explanation of spacetime diagrams. I think other books explain S-T diagrams a little better but then again I haven't completely finished reading this chapter of the book. He does explain the twin paradox and pole in barn paradox using those s-t diagrams.
Great effort by Mermin.

Mermin's presentation of special relativity is a scientific, literary, and pedagogic masterpiece. It is one of the rarest of technical and scientific books: it offers immense value to the full spectrum from rank beginners to grizzled educators and practitioners.

My PhD work in physics and astronomy began more than 40 years ago, and I recently decided to "relearn" relativity from the very beginning... something that other almost-retirees can appreciate. (It's a corollary of "Youth is wasted on the young": ... So is relativity!!) Starting with time-worn texts I already own, I soon realized that they (and more recent ones as well) were NOT addressing the most common nagging questions satisfactorily. I could appreciate the postulates and their background, and reproduce all the derivations in detail, but they all seemed to lurch at the most inopportune moment, when genuine insight might have been anticipated.

My self-imposed goal had been to cultivate a level of intuition that I knew was possible but had always been elusive. The miracle, of course, is that SR *does* allow for intuition, just as I suspected; setting the stage for that intuition is precisely where Mermin excels beyond measure. The derivation of relativistic velocity addition in Chapter 4 WITHOUT invoking clocks and meter sticks simply must be seen ... and savored ... to be believed. Mermin deserves a Nobel Prize in pedagogy.

With all due respect to you-know-who, there are many moments in this book that out-Feynman Feynman by effortlessly conveying deep and broad insight ... while fully enabling the reader to carry that ball alone. Stunning.

In the space of one week, Mermin's book has become one of my most prized of a lifetime. Now I remember why I first fell in love with physics. Ninety-nine stars for this one.

Relativity is a damned hard subject to fully comprehend, but it is an important part of being an educated person. Without this knowledge, one can occasionally make a serious mistake in judgment and be dead wrong about certain things. David Mermin explains the necessary thinking in a beautiful, skillful way. I can't imagine his making it clearer or simpler, but nevertheless, it is a HARD bit of reasoning to master. This short book requires reading word-for-word and then some rereading, but this is not a burden. It is written with a light, pleasant touch that is a delight and I fully recommend it to anyone ready to make a serious effort at understanding the real world.

This is fantastic. The best thing is that it teaches the reader relativity via its mathematics and not just through words. The author also labels those mathematics that are perhaps too hard clearly for readers to skip if he or she likes. Only through the understanding of the mathematics underlying relativity can one really appreciate what it is all about. An immensely amazing book.

If you've been away from the topic for a while it can be frustrating when you return to it when an author makes great leaps in logic or even algebra. This books fills in those details nicely for casual or rusty readers.

The one piece that is missing (and seems to be missing from all relativity texts) that would be great for the casual reader is a discussion of the evidence (theoretical and experimental) for the constancy of the speed of light. Since relativistic derivations take this as a given it would nice to be reminded how we know this is so.

Introduction of formulas a priori with only consecutive derivation is preceptionally inadequate. This combined with too a verbose and insufficiently organized progress of the argument makes for an uneasy reading.