Einstein's Legacy

This post is a short review of the book Einstein's Universe by Nigel Calder. The book came out in 1979, celebrating the 100th anniversary of Einstein's birth, and had the same title as the BBC film released on that occasion (whose script Calder wrote).

Although the book is almost 45 years old, it is interesting because Einstein's science is still good; also I found the subtitle on the cover - "Relativity Made Plain" - alluring.

The book mainly covers special and general relativity (black holes, pulsars, gravitational waves), though it mentions the phenomena of the photoelectric effect and stimulated emission as well.

Over 21 short chapters (the book is 154 pages long) interesting descriptions are provided for how to weigh a black hole (from the dynamics of the nearby stars), why a pressing iron is heavier when hot (because energy equals mass), how Dicke's theory of relativity (which assumes the gravitational constant changes with space and time) compares with Einstein's. I found the speculation about finding gravitational waves interesting, because the book dates back to way before they were first observed in 2016.

The author definitely has a sense of humor. The book has several amusing observations - as to why relativity is a bad name for the theory, how we can satisfy all our energy needs by dumping our trash into a black hole, how if you travel fast you will age slowly, but gain more weight.

I found a couple of statements somewhat confusing - for example, the book associates light (because it has energy) with mass (but photons are massless!). Some statements of course need to be updated - the book acknowledges that the universe is expanding, but that the rate of expansion is accelerated (driven by dark energy) was established much after the book was published. Still, it is quite amazing how much of the book's content is still pretty much valid today.

The book ends with a treatment of Einstein's discomfort with quantum mechanics, and a good summary of the qualities made Einstein great as a scientist - scepticism, childlike wonder, good intuition, introversion and persistence. Not, as the book notes, great mathematical dexterity. It reminded me of one of Einstein's quotes that I really like:

"Most people say that it is the intellect which makes a great scientist. They are wrong: it is character."

Summary

The book is written with verve and makes for good reading even today. Calder's experience in communicating with lay audiences shines through. A number of very distinguished scientists are acknowledged for help - Dennis Sciama, Irwin Shapiro, Roger Penrose, Wheeler, Sydney Drell, etc. Maybe the number of chapters could have been condensed. There's a good number of diagrams and photos (e.g. of rockets etc.). Worth reading if only to gauge how the world was responding to a hundred years of Einstein's work.