Black Holes

So I finally finished Black Holes and Time Warps the other day. I've had it for a very long time--it was one of the first books I got as part of the 5-for-$1 deal when signing up for the book of the month club way back in high school (once I began earning disposable income). I almost got rid of it with a bunch of other books when moving out to Virginia, but I decided to actually read it first before I try to sell it back. It wasn't really worth the wait.

One of my biggest peeves with the popular science non-fiction genre is how dumbed down everything is. And all the books about relativity and cosmology use the same old analogies that break down when you're talking about actual real-world situations. Kip Thorne's book is different in that he tries to explain the nitty gritty details about Einstein's equations, relativity, and black holes, and he uses the actual analogies that physicists use when talking to each other, not the dumbed down analogies. However, Thorne still utilizes my second peeve: the lack of equations. For people like me, sometimes a simple equation makes a concept crystal clear. About halfway through the book, Thorne runs out of straightforward explanations and analogies and is forced to start making blanket claims about black holes, and at that point I start asking "why?". How does topology prove every black hole has a singularity? How can a spinning black hole create a "naked singularity" (a black hole that is not "black")? Reading Thorne's labored descriptions of how black holes must only "grow larger" or how they "radiate" make me wish he could include a few straightforward equations to show why this is so. The whole chapter about gravitational waves without a single equation made me cringe. Some equations are found in the footnotes, and it's funny to read a page and a half of explanation and then to read a two sentence footnote with an equation that makes everything finally clear.

There are three things I liked about the book. First, it finally convinced me that black holes are real and not simply a mathematical toy that physicists like to play with. Well, the recent Nova episode helped, where they actually observed stars getting flung around a blank spot in the center of our galaxy. Secondly, the book placed everything in a historical context. It could almost be considered a history of science book because it credits everybody for their individual contributions to the field. It also shows how the field built upon the ideas of previous researchers. That was pretty interesting, and I finally was able to hook some names with ideas, and to also learn new names which I'm noticing all the time now (e.g. Jansky Fellowship for radio astronomy). And third, Thorne makes it explicit (albeit later in the book) that the hyperspace dimension in which spacetime is bent by mass is NOT real, but only a mathematical construct. I really hate it (especially in quantum mechanics) when authors take equations and interpret them literally when that is not their purpose. Thorne even takes the time to explain that in certain situations, physicists use a spacetime-warping model for some situations and a "flat" spacetime-compressing model for other situations, just as how we treat subatomic particles as particles or waves as the situation requires. I applaud him for that.

So bottome line, I would say the first ~300 pages or so (up to chapter 8) of the book are a pretty good thorough popular science introduction to relativity and black holes. I wouldn't necessarily say it's an exciting read (chapter seven was kind of boring, even though it had a lot of cool concepts in it), but it explains black holes pretty well. There are two nagging questions I still have. First, I would like a better explanation of how the black holes grow and shrink (can black holes disappear if nothing is added to them?). Second, the book does a pretty good job explaining why only stars of sufficient mass can become black holes (smaller stars become neutron stars for white dwarfs) but I keep hearing things about tiny black holes, especially the kind that can be created once the LHC is finally operational. So how can a black hole exist below the Tolman-Oppenheimer-Volkoff limit?

Slightly off topic, I am still waiting for that popular science book that is geared for people with a good algebra background. Most books are either way too dumbed down (with no equations) for actual textbooks (= dry and boring with too many equations and not enough explanation). Maybe something with normal text for the layman and side boxes full of equations for the scientist. Actually Shadows of the Mind by Roger Penrose did a really good job of that. But then Penrose starts talking about M-branes and I get lost again. Maybe I should try reading that book again, or maybe his most recent monstrosity.