As the universe darkens

 kw: book reviews, nonfiction, cosmology, dark energy, dark matter

I had one expectation when I saw the title: Fear of a Black Universe: An Outsider's Guide to the Future of Physics by Stephon Alexander. I surmised that it was literal, though metaphor is always possible. As it happens, Dr. Alexander means it both ways. He is black, and in the physics community, that makes him an outsider. Sad to say, institutional racism is more entrenched in academia than it is in most of suburbia, where I dwell.

I will not dwell on the author's reports of prejudice. Being white (or, having no more than about 1/16th African ancestry), I've seen such things from a different perspective than he has. Some aspects of what he is, he has been forced to become. Whether in spite of such handicaps or because of them, he is an excellent scientist (Neil deGrasse Tyson, another black scientist I admire, freely admits he "over-achieved" in reaction to being discriminated against). Suffice it to say, it was clear that the colleagues who denigrated him did so out of fear, thus the book's title. His significant achievements indicate that their fear was well-based, though ill-conceived.

This illustration explains why the universe is becoming darker, tending toward a future of infinite, unending blackness.

According to the cosmology accepted by a great many, something, dubbed "dark energy", is causing the expansion of the universe to accelerate. Some conjecture that at a time between one and 10 billion years in the future, the acceleration will increase rapidly, leading to a "big rip", eventually even dragging atoms apart, leaving nothing material remaining. Others expect something more sedate, but still leading to the "nearest" galaxies being too far away to see, and resulting in the dissolution of galaxies. If living beings remain on any planets in such a universe, there won't be a starry sky. The "sun" will be the only star visible.

Much of the book describes in laymans' terms the observations and hypotheses behind the understanding of "dark matter" (stuff that gravitates but doesn't shine) and "dark energy" (something about space that pushes it apart, ever more rapidly).

Cosmology is a difficult science. If you were to study chemistry, you could do experiments that take place in minutes or hours or days, typically…although I do recall a reaction that required about a month's exposure to the UV light in sunlight. The second term of my Organic Chemistry course, we performed a synthesis that began with the usual "measure carefully, mix thoroughly" stuff, and then we stoppered our flasks and set them on a windowsill until halfway through the term.

There's no such alacrity possible if your subject is the history of the universe. Tons of interesting stuff happened billions of years ago, that doesn't happen now, so astrophysicists have to infer what it was by looking for subtle signals in the light (loosely construed: wavelengths from gamma rays to radio waves) arriving from space. No "experiments" are possible. How can you repeat something that took 12 billion years to happen?

Modern supercomputers can simulate really huge systems at incredibly high speed. That's not enough (yet?) to permit a useful model of the whole universe to be built and run in a useful amount of time. So a lot of theorizing goes on. A LOT!

Dr. Alexander likes string theory. After reading his explanations, however, I was no closer to understanding string theories than before. "Theories": there are a lot of them; the most recent estimate is upwards of 10⁵⁰⁰ of them (that's a number with at least 500 digits. The number of atoms in the universe can be counted with 80-85 digits).

In the last chapter or two the author writes of the theory that, based on the Copenhagen Interpretation of Quantum Physics, nothing exists until it is observed. The Copenhagen Interpretation was the brainchild of Niels Bohr. Quite frankly, I disagree, but I'll get into that when I review another book on that subject in particular, which I've just begun to read.

I am also skeptical of the existence of dark energy, or the cosmological constant, or whatever it is currently called. I have read a number of journal articles challenging the premises on which it is based. It posits a kind of "vacuum energy" that, if it exists, should be 10¹²⁰ times as large as it is claimed to be. To me, that's the largest error so far to be found in any theory I know of. Dr. Alexander has a humorous possible solution to that dilemma: Aliens, great multitudes of them, who can harness dark energy for their own uses, using a "gravitonic computer". The amount of dark energy we observe is the trickle that is left over, leakage from their technology. If that were so, there's a lot of waste heat that has to go somewhere, enough to boil every planet and star in the known universe trillions of times. Second-biggest error? Maybe!

So, the book was enjoyable to read, but I am afraid I didn't gain much enlightenment. Dr. Alexander is a brilliant physicist. I'll have to read more, multiple times, to grasp where he is going.

If you don't like errata, you can stop here. I noticed a couple of things that slipped past the proofreader or copy editor:

• On page 184, discussing the gravitonic computer, two numbers are presented, shown as 10,120 and 10,100. These should have been represented as 10¹²⁰ and 10¹⁰⁰. These are just typos.
• On page 197, two theories of gravitational wave spectra are discussed. One is said to be more "red", the other more "blue": "In inflation the power spectrum is said to be red. This simply means that the longer wavelength perturbations have slightly less power than the shorter wavelength ones." No, "red" means longer wavelengths are stronger, while "blue" means shorter wavelengths are stronger.
• On page 205, John von Neumann is said to have "proved that when a quantum system exists in a superposition of states, a chain of measurements ultimately leading to the consciousness of an observer is what collapses the wave function into one definite state." This is based on the Copenhagen Interpretation, and it is a claim, that so far has not been proved. It cannot be proved. All experiments that purport to prove it, and I have read about many of them, ultimately depend on circular reasoning.
• Two things on page 206: Firstly, Erwin Schrödinger is said to have predicted the basic helical structure of DNA. He actually predicted a regular, aperiodic structure, akin to a crystal but with variable items at each node, so it could carry information. Language is a useful analogy. The helix was posited later, by others. 
• Secondly, Schrödinger "argued that living things fight against entropy, otherwise known as negentropy." He did indeed, but better reasoning has overtaken that theory: living things take advantage of the flow of energy in non-equilibrium environments, and thus they take advantage of the flow of entropy as well, producing small, local reductions in entropy at the expense of larger increases in entropy in their surroundings. That's not "negentropy", it is redirected entropy.

The last item may not be a copy error, but a conceptual error on the part of the author. He goes on to discuss the "observation creates reality" theory, based on the assertion by von Neumann, which has been developed by many others. This isn't physics any more, it is metaphysics, and ought to stand on its own two feet and proclaim so. That's enough at the moment.