★★★★☆ Black Holes: The Key to Understanding the Universe, by Brian Cox, Jeff Forshaw
Good but demanding popular presentation of the science of Black Holes
Black Holes: The Key to Understanding the Universe
Brian Cox, Jeff Forshaw
Good but demanding popular presentation of the science of Black Holes
If you are like me, the first thing you think on reading the title of Brian Cox and Jeff Forshaw's Black Holes: The Key to Understanding the Universe is "Isn't that subtitle a bit overstated?"
Yes, yes it is. Black Holes is, nevertheless, a very good book.
The first thing I like about it is that it doesn't begin with the usual 4-6 chapters intended to bring the ignorant reader up to speed on the physics revolution of the early twentieth century. If you've read a lot of popular physics book, you know what I mean. Instead of this one-size-fits-all approach, Cox and Forshaw explain things as they need them.
We begin with an introduction to Einstein's theory of gravity. We move fairly quickly to what a black hole looks like in general relativity. Somewhere in there Penrose diagrams, used throughout the book, are introduced. We then move to Hawking radiation, black hole thermodynamics, and the black hole information paradox. At around this point the holographic principle is introduced. We end with speculation that the universe is a natural quantum computer and that space and time and gravity may be computationally generated. (I will note here that Cox and Forshaw are not joining in the speculation that we live in a simulated reality -- they are clear about that.)
I enjoyed this a lot and found it stimulating and enlightening. However, I will state as a warning to other readers that it was not easy going, and I have a PhD in Applied Mathematics. One thing I liked is that Cox and Forshaw work very hard not to dumb things down to the point of getting the physics wrong.
As an example, Black Holes is one of the few popular physics books I have read that accurately explains entropy. Most pop phys books will tell you that entropy is disorder. This is either vacuous or completely wrong, depending on how you define "disorder." Entropy is a measure of ignorance. Specifically, the entropy of a physical system is the amount you don't know about it. Yes, that is weird and puzzling in all kinds of ways. But it has the advantage of being correct.
If I have a complaint about Black Holes, it is that much of it is speculative. Speculation is fine, but Cox and Forshaw don't carefully police the border between knowledge and speculation. I felt, especially towards the end, that they very nearly presented as true things that no one really knows for sure.
If you're willing to work hard at understanding physics and math, and to approach ideas in the right spirit of skepticism, Black Holes is a very good book.