The Little Book of Black Holes by Steven Gruber and Frans Pretorius

Source of book: Borrowed from the library

Occasionally, when I am at the library, I find a science related book to bring home for my 12 year old son. He is very much into science and technology, and finds these books fun, even when they aren’t exactly aimed at kids. In this case, this book was on the new books shelf and looked interesting. He read it first, and I thought it looked worth a read. Having read it, I am sure the math parts (and some of the science) were a bit over his head - but I have learned that he picks up a surprising amount from books like this. I am sure I will hear about it later.

In general, I am fascinated with astrophysics and astronomy, even if my limited math skills (I never did get to calculus) make some of the specifics hard to grasp. Previous selections include Phil Plait’s excellent and accessible Death From The Skies and David Weintraub’s more detailed How Old Is The Universe? In this connection, I should also mention The Hunt for Vulcan, about the way that an anomaly in Mercury’s orbit led to the discovery of relativity and a new theory of spacetime. In many ways, this book takes up the topic where the previous one left off.

This book is fairly short, and focused on one particular topic: Black holes.

One of the paradoxes of black holes are that they (by definition) cannot be “seen” in the traditional sense. Since light (electromagnetic radiation) cannot escape the event horizon, one cannot “see” the object at all. Instead, their existence is shown by two things: math, and their effect on objects we can see.

It was interesting that the math came first. One of the most amazing things about the universe is that it was written in the language of mathematics. Indeed, many discoveries have postdated the mathematics necessary to understand them. (Love and Math by Edward Frenkel is a fantastic book on this subject.) In this case, the existence of objects with the characteristics of black holes was mathematically predicted as early as the immediate aftermath of Einstein’s theories of relativity. Our technology, however, wasn’t yet able to provide the observational evidence.

Later, as our telescopes got better, and especially after we put them in space, we were able to observe the gravitational effects of black holes. Specifically, we were able to observe binary systems where the only explanation that worked was a black hole. (And later, the calculations of how galaxies like our own worked showed that a supermassive black hole was necessary at the center.)

More recently - and practically - evidence of gravitational waves and gravitational redshift (both predictions of general relativity) has been proven thoroughly. In fact, GPS has to take into account special and general relativity AND gravitational redshift in order to be accurate. A rather small force turns out to mean a lot even at short distances.

This book takes you through the theoretics, the observations, and some really, really crazy theoretical physics at the end. After all, despite the event horizon and all, black holes DO leak energy, and the way this works is pretty dang mind blowing.

The book is written by Steven Gruber and Frans Pretorius, both of whom are physics professors at Princeton. It is no surprise that they know their stuff. But they also write quite well, explaining tough concepts in an understandable way, without talking down to the reader. Gruber also wrote The Little Book of String Theory, which might have to go on my list.

Whether you start with this book really depends on your existing knowledge. If you glazed over at “event horizon,” this is probably not the place to start. Get a copy of Death From the Skies - or maybe a high school level astronomy textbook. If event horizons are okay, but you can’t remember what pulsars, quasars, and neutron stars are, you might want to read How Old is the Universe? to get a better overview of stellar objects in general. That book will also help with the math and physics of how we know there is an expanding universe, how we judge distances, and how we use math and observance to figure stuff out.

But, with a good background, this book is really quite fascinating. As some have pointed out (particularly in the wake of Stephen Hawking’s death), we haven’t ever “seen” a black hole, but we have strong evidence that they exist, and that they have specific characteristics and effects on the rest of the universe.

How Old Is The Universe? by David Weintraub

Source of book: Borrowed from the library

“I do not feel obligated to believe that the same God who has endowed us with senses, reason, and intellect has intended to forgo their use...He would not require us to deny sense and reason in physical matters which are set before our eyes and mind by direct experience or necessary demonstrations.” ~ Galileo Galilei (1615 CE)

To a degree, this book is a follow up selection in my self-education regarding astrophysics. A couple of years ago, I read Philip Plait’s excellent and thrilling Death From The Skies, which uses the idea of “things which could destroy our planet” to give an overview of astronomy and astrophysics. While an overview, it doesn’t get too in depth about specifics, which makes it a good introduction to the average reader, rather than a scientific text.

How Old Is The Universe is likewise not a scientific textbook, but it goes much further into the math and physics - so much so that it probably would help to brush up on geometry and physics a bit before reading it. And maybe a bit of chemistry too for good measure. High school level is probably okay, but this book will stretch it a bit.

This is not to say this book is boring. Quite the contrary. While not exactly a page turner, it is written in an accessible style, and the author does a fine job of bringing the difficult stuff down to the level of us mere mortals. I particularly found his analogies to be helpful in explaining some of the higher concepts.

I began this post with the quote from Galileo for two reasons: first, it opens the book itself. Second, it encapsulates my view of science and its relation to theology. I have never been able to believe that God intentionally created a “fake” universe, one where appearances flatly contradict the “reality” we are supposed to believe in spite of the evidence. That would seem to make God a liar, and a cheater to boot.

I mention this specifically because my particular theological tradition has spent a tremendous amount of energy and political capital trying to deny the overwhelming evidence in favor of an old earth and an older universe. I discussed this in more detail in my post on Young Earth Creationism, here.

One of the biggest lies that YEC feeds you is that the scientific establishment is one giant conspiracy. Supposedly, “everyone” knows that the earth is really 6000 years old, but they deny it because they want to sin (usually by having sex) and the truth interferes with that desire. I know, that’s what I was taught.

Of course, this is a huge slander against the tens of thousands of conscientious scientists who have followed the evidence to the conclusions they have reached, not out of some rebellion against God, but because that’s what the evidence shows. This group also contains many Christians who do not believe the evidence conflicts with faith, just with certain theologically driven conclusions.

Galileo himself was one of these, and yet he was punished brutally for going against current dogma. Even St. Augustine cautioned against giving theology priority in scientific matters, specifically warning against making literalism a stumbling block to acceptance of reality.

Unfortunately, the perceived theological need to take everything in the Bible literally, and as literally true in all details has led to an abandonment of this principle and open hostility toward science of all kinds.

(I want to specifically mention the denial of the biological reality of intersexuality, which I wrote about here, as a clear example of perceived theological needs trumping reality.)

Peter Enns put it best:

Theological needs – better, perceived theological needs – do not determine historical truth. Evangelicals do not tolerate such self-referential logic from defenders of other faiths, and they should not tolerate it in themselves.

One of the best things about this book is that it gives the history of the discoveries that have led scientists to understand the age of the universe. Discoveries that seemed at the time to have nothing to do with the question turned out to be vitally important. Furthermore, it isn’t just one area of study that leads to the conclusion, it is multiple unrelated pieces of evidence which agree about the age of the universe. The pieces weren’t assembled by any one person, or at any one time. Rather, they came together over the last 250 years as the result of many thousands of scientists around the world working on different pieces, building on the work of those who had gone before. To many of them, the results were a surprise, the age determined unexpected. Many times, an unexpected result caused a wholesale revision of their assumptions.

These are not the things of a conspiracy, but of a process of discovery. And the more information that is gathered with ever-more-sophisticated tools, the more solid the conclusion has become.

The author begins the book with a quick look at ancient beliefs about the age of the universe, ranging from “the universe is eternal and unchanging” to “the universe was created on October 23, 4004 BCE, at 9:00 AM.” The last, of course, came from the work of James Ussher and John Lightfoot. The former came from Aristotle. As the author points out:

Aristotle’s logic and reasoning were elegant, sophisticated, powerful, and regrettably also wrong.

Therein lies the rub. Theological and philosophical systems often have elegant, harmonious, and persuasive symmetry, so to speak. But they can often be dead wrong. Aristotle’s perceived philosophical needs didn’t fare so well when they ran into reality, and neither did Ussher’s theology.

I do want to mention a few things that I particularly liked. First, Weintraub doesn’t make the mistake many earlier writers did of glossing over the contributions of women to the field. While notable women such as Henrietta Leavitt and Annie Jump Cannon are becoming better known, it is only in the last few years that the truth regarding the mathematical calculations before the age of computers has been stated: the mostly male astrophysicists who get credited with discovery relied on veritable armies of female “calculators” to do the work of measurement and calculation necessary to process the data. So much for women being bad at math.

I also should mention that this book did a better job of explaining the concept of expanding space than any other I have read. I knew this was a key concept of modern astrophysics, but I hadn’t quite realized why it was important or how it came to be accepted as an explanation. I won’t attempt a recap of it here, because I would probably butcher it. Read the book if you want to find out.

Because the book is presented as much as a history as an answer to the question, the concepts build on each other much like they did in real life. But this also means that the math and the concepts get progressively harder as the chapters go on. By the end, those of us without science degrees tend to find our heads spinning a bit. But that is good. It’s good to be stretched, and be forced to think and make links between concepts of chemistry and physics and algebra.

The universe turns out to be the greatest puzzle of all time, with clues hidden everywhere. I can fully understand why astronomers consider their particular area to be the most fascinating thing to study possible.

I am strongly considering getting this book for a reference, and I will definitely be recommending it to friends who want to know why I believe what I do about the age of the universe, or understand better what we have discovered about the wonders of this world we find ourselves in.