It's about Time: Understanding Einstein's Relativity

It's about Time: Understanding Einstein's Relativity

It's about Time: Understanding Einstein's Relativity

It's about Time: Understanding Einstein's Relativity


In It's About Time, N. David Mermin asserts that relativity ought to be an important part of everyone's education--after all, it is largely about time, a subject with which all are familiar. The book reveals that some of our most intuitive notions about time are shockingly wrong, and that the real nature of time discovered by Einstein can be rigorously explained without advanced mathematics. This readable exposition of the nature of time as addressed in Einstein's theory of relativity is accessible to anyone who remembers a little high school algebra and elementary plane geometry.

The book evolved as Mermin taught the subject to diverse groups of undergraduates at Cornell University, none of them science majors, over three and a half decades. Mermin's approach is imaginative, yet accurate and complete. Clear, lively, and informal, the book will appeal to intellectually curious readers of all kinds, including even professional physicists, who will be intrigued by its highly original approach.


Absolute, true, and mathematical time, of
itself and from its own nature, flows
equably without relation to anything
Isaac Newton

My time is your time
Rudy Vallee

It came to me that time was suspect!
Albert Einstein

The year 2005 is the centenary of the publication of Einstein's special theory of relativity. Forty years earlier, in the 60th anniversary year, as a new young assistant professor of physics at Cornell, I decided that it was about time to make relativity a standard part of the high school curriculum. This can be done by incorporating it into courses in elementary algebra or plane geometry, which are, surprisingly, the only technical tools required for a full understanding of the subject. So I taught a course on special relativity to a group of high school teachers, and they seemed to enjoy it.

Relativity is perfect for the high school curriculum not only because it offers an astonishing application of elementary high school mathematics, but also because everybody is intimately acquainted with the subject of relativity. Relativity is about time. What could be more familiar? What makes the subject so fascinating is that relativity reveals the nature of time to be shockingly different from what had been taken completely for granted, up until 1905. We now know, for example, that the first two statements that open this preface are incorrect. Understanding why Newton and Vallee were both wrong about time ought to be an important part of anybody's education. The wonderfully succinct characterization, in the third statement, of the key to a mystery facing physicists at the start of the 20th century is from a report of a private conversation with Einstein, toward the end of his life.

R. S. Shankland, “Conversations with Albert Einstein,” American Journal of Physics
31(1963): 47–57.

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