BTRIPP (btripp) wrote,

Holy Bubble-Blowing Black Holes, Batman!

This was a relatively recent dollar store find (about six weeks back), but I was sort of looking for a science book to get into, and that category has gotten somewhat lean in my to-be-read piles, so this leapt to the front of the line. While being a “popular” science book, Caleb Scharf's Gravity's Engines: How Bubble-Blowing Black Holes Rule Galaxies, Stars, and Life in the Cosmos is not exactly a light read (OMG, I came very close to making an inadvertent black hole joke there), as it is filled with a whole lot of fairly complex information on cosmological discoveries, much of which was at least reasonably new to me (this came out in 2012, so the material should be fairly up-to-date – as much as one can expect from any technology book).

I don't know if this is a compliment or a fault, but when I picked this up to do the review, I was having a hard time “off the top of my head” recalling the specifics. The “broad strokes” I got, but the book, in my mind, sort of existed as a unified whole. This, on one hand, means that everything in here “hung together” well, but it might also mean that this got sufficiently technical to have lost me on the details. Fortunately, I do have a few of my little bookmarks scattered through it to point me back to what I felt were the notable parts.

Now, this is full of very complicated concepts that Scharf attempts to present in terms that will make sense to “the average reader” … one of the images he uses is of a sack containing “a representative portion” of the universe. This not only lets him introduce the idea of generalizing from “a fair sample” of data points, but allows him to talk about stuff “streaming out of” said sack. A significant amount of this are photons …
They come in all flavors, from extremely low-frequency radio waves, where a single crest-to-crest distance may span kilometers, to microwaves, infrared, visible, and ultraviolet frequencies, and on to the realm of X-rays and gamma rays. One of the most pervasive types of photons is the kind that originated in the very young universe ...
This serves to introduce the “cosmic microwave background” photons – which are present in our local neck of the universe at about 410 per cubic centimeter, meaning that the immediate (within one light-year of the Sun) neighborhood has about 1057 (more than a trillion trillion trillion trillion, and that's a lot) of them zipping around at any given time. That leads him to discussing neutrinos, which react so little with normal matter that you might have a collision between a neutrino and a sub-atomic particle comprising some part of your body maybe only once or twice in your lifetime – despite there being somewhere around 65 billion of them streaming out of the sun and passing through “every square centimeter of your skin” every second.

From here he discusses other matter, then briefly touches on Dark Matter (somewhat “in passing”, since we currently know next to nothing about it), and on to gravity, and how things seem to be structured in the universe in general. Now, I have to confess that I have no bookmarks through most of the middle of the text, so I'm going to be flipping through to give you a sense of what's in there. I do want to stress, however, that this wasn't due to it being boring or uninformative, but possibly being “too much” data flow for me to be able to say “oh, hey, let's highlight this”, or the like. One thing that did catch my attention was his “borrowing” of some of Doug Adams' imagery (in the form of a falling whale to illustrate tidal forces, and a likewise fatally descending bowl of petunias) which he only obliquely cites in an endnote. This opens up discussion of Einstein's “field equation”, and Karl Schwarzschild's solution to that (and the resulting concept of the “Schwarzschild Radius” of a given spherical mass and the idea of the “event horizon”), which then leads into a look at gravitational contexts, including an interesting chart showing the relations of mass, size, and speed (or “terminal velocity”), where an object hitting the Sun will achieve 0.2% of the speed of light, but a black hole of the same mass would have objects coming in at the speed of light. Oh, and how the gurgling of water going down a drain has its equivalent in emissions from a black hole … yes, he explains how that works, but I can't even begin to relate that here.

Scharf goes into the history of x-ray research, from its earliest forms through programs of increasing complexity, leading up to the current generation of x-ray imaging satellites. It seems that x-rays are the preferred means to look at the environs of black holes, and especially phenomena that are hugely distant (and hence vastly old) and visible in ridiculously small areas of the sky. There are some fascinating images of objects remarkably far away (one at a 600,000,000 light-years remove), imaged in x-ray, microwave, radio, and occasionally visible light … although I think these would be improved had there been more “comparative” images (Scharf often describes what the visible light image would look like, but its up to the reader to fill in the picture around the “inner elements” exposed by x-ray, etc., capture).

The author also goes into a good deal of the sub-atomic particle physics that comes into play in some of the reactions posited for these most violent areas of the universe. Given that the stresses, speeds, temperatures, etc., etc., etc., can reach their utmost extremes in these zones, the behavior of all forms of matter are taken to their ultimate limits, and produce extraordinary effects. Again, there is such a “firehose” of material here, it's pretty useless for me to try to excerpt it, as it might take pages of blockquotes to get to where I feel I'm making it clear (which is, I guess what this book is for!).

The early history of the universe is contemplated, with surmises presented as to early galaxy formation, as well as outlines of the basic types of galaxies, the massive number of stars involved in these, their assorted sizes, etc. At most points the author tries to offer up examples that can help the reader “wrap their head around” these difficult concepts (like comparing the fluid dynamics of water coming out of a garden hose to how jets of material can shoot out hundreds of light-years from celestial objects), while (kindly?) skipping most of the math. He is constantly trying to put these things in terms that at least suggest to the reader how they relate to “knowable” stuff, such as:
While a supermassive black hole can occupy a volume similar to that encompassed by the orbit of Neptune, a big cluster of galaxies can occupy a region some 30 million light-years across. The black hole is only 0.00000000001 times the size of the cluster. That's the size of the period at the end of this sentence compared to one-third of the distance to the Moon.
Frankly, one of the main take-aways for me with the whole book was the extreme nature of all this … the hugeness, the distances, the time involved, the masses (a supermassive black hole can have a mass 12 billion times that of the Sun), the warping of space-time (which can be twisted into something akin to a tornado in some settings), etc. ...which is really difficult to fully appreciate or even effectively contemplate!

Of course, one of the factors here is that so much of this is based on “best guesses”, it's amazing that we're able to get the data that the scientists are working with, but they're having to have some of the most expensive technology ever invented by man devoting hours and hours and hours of readings to just get enough photons on a chip to be able to suggest what's going on (as most of these targets are incredibly distant and fill the most infinitesimally small portion of the sky). An example of this is here:
The most distant quasars exist in a very young universe, barely a billion years old. As we've seen, quasars are products of the appetite of the biggest and best-provisioned black holes. Surrounded by accreting matter, they pump out a prodigious amount of energy. But the age of these systems raises a fundamental question. These supermassive black holes must have formed contemporaneously with the first generations of stars in the universe. This is a great puzzle, because the way we think black holes form in today's universe is from the catastrophic collapse of massive stellar remains. Once the mass of a spent stellar core or an object like a neutron star exceeds a certain threshold, there is only one way for it to go: down and in. There is no known pressure force that can resist the shrinking of such an object to inside its event horizon. But this produces a baby black hole only a few times the mass of our Sun. Even if it eats matter at the rate required to power something like a quasar, that amounts to only a few Sun's worth of material a year. With a continual food supply, it would still take hundreds of millions of years to reach supermassive scales. So where could those first giant chasms have possibly come from? {he does offer up a few possibilities here}
One thing, on a more human scale, that I don't believe that I'd previously heard of was the “Galaxy Zoo” project which used “crowdsourcing” to help categorize 500 million astrophysical objects detected by the Sloan Digital Sky Survey. This site ( started about a decade ago, and at the time of this book's writing (in 2012), over 150,000 people had helped classify 50 million of those objects (each of which was getting 20 different classification hits to assure accuracy).

There's so much stuff in here … things like the most massive black holes in spiral galaxies are about the same size as the least massive black holes in elliptical galaxies … or that our galaxy, the spiral Milky Way, is quite large for its type and is termed a “green valley” galaxy which is in the middle zone between the “red” of the ellipticals and the “blue” of some other spirals (plus having very “active” black holes at their centers) … which leads the author to speculate on some “anthropic” concepts in relation of our existing where we do,

Anyway, Gravity's Engines is a fascinating read … and if you have an interest in cosmology, astronomy, physics, etc., you should definitely consider picking up a copy. As I noted at the top, I got the hardcover of this at the dollar store, and it looks like it was one of those “right store on the right day” finds (with the books coming in from their likely source of Walmart clearing their shelves), as it's still available as a hardcover, paperback, and ebook from the on-line big boys (so is likely to be able to be found a your local brick & mortar that handles science books). And, even having hit the after-market, it's still going for a few bucks in the new/used channel. If you like science, you'll probably like this one a lot.

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Tags: book review
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