kw: book reviews, nonfiction, science, biology, exobiology, origin of life, evolution
(It took a while to "persuade" OpenArt to make the base image, one to which I could add the other elements.)
I was surprised to find that in a book this small (just over 300 pages), the authors would deal with the two biggest questions that exist: "How did life arise?" (the question behind "Where did we come from?") and "Are we alone?" The authors survey what is currently known about the abiotic→biotic transition in six chapters, and they present the multitude of methods for finding signs of life off-Earth in six chapters. The final chapter summarizes the whole.
Concerning the chemistry and physics that might have engendered the first living cells, one must get a bit technical. So much so that they include an appendix to Chapter 3 ("From Chemistry to Biology") that one might call a pre-Primer for Biochemistry 001. In biochemistry as in geochemistry, chemistry is geometry, because the shapes of molecules matter. In fact, much of biological evolution has been taken up with creating innovative and useful molecular shapes for "doing things" (that is, proteins, particularly enzymes). This pre-Primer introduces this kind of geometrical chemistry.
Thus, Chapters 3-5 show the results of breakthroughs in recent years, that broke through a logjam that confounded the science of biotic origins for decades. They describe in particular the way certain necessary molecules could have been assembled step by step, rather than all-at-once, as earlier hypotheses required.
There's no need for me to get into the weeds about that here. I'll just touch on this impression: Chapter after chapter filled with "could be" and "might have" sorts of statements begin to sound like a case of terminal arm-waving. What rescues this section from that fate is the salient fact that we really don't know what happened between the period, starting almost 4 billion years ago, and lasting about 0.2 or 0.3 billion years, until the time of the first unambiguous fossils of biological "something", and the time that the chemistry of Earth, its atmosphere, and its oceans, had changed enough to support whatever living beings then existed. We have a somewhat good idea of the chemistry of some 3.5 billion years ago, but only the rawest speculation about what came before. We surmise that the change came about largely because of living things, just as the later Great Oxygenation Event made an even more radical change. We still have a lot to learn!
As to, "Who might be out there?"…the only "experiments" we can perform are the various kinds of detection technologies: Telescopes of the optical, ultraviolet, infrared, and radio varieties. Contrary to the claims of the UFO (and now UAV) communities, there is no (publicly known) and concrete evidence that some kind of space aliens have visited or are visiting. A big part of the budget of NASA is devoted to ET-finding technology. It's great that a few exoplanets can now be seen, though not in any detail, and that thousands have been detected and catalogued.
I once read a short story in which a signal is detected by SETI (the Search for Extra-Terrestrial Intelligence, conducted with radio telescopes), and is found to be encrypted. The story ends with the protagonist wondering if the source is military in nature, which would not bode well for future relations. I wrote to the author, "Perhaps if the signal gets decoded, it will be bank transactions or inventory records."
It's sobering to consider that the signals we have sent off into space by our radio and TV signals have yet to reach beyond about 100 light years, and if "someone" at a distance of 50-100 light years is listening in our direction, with technology at our level, they probably cannot yet detect it. Maybe in another 10-20 years…
Enrico Fermi's question still resonates: "Where is everybody?" How plausible is it that we are at the forefront? That, at least in a bubble a thousand or so light years in radius, we are the first planet with life to develop a civilization? Consider that it may be necessary for the Universe to evolve for 8-9 billion years, to produce a generation of stars with enough metallicity to have rocky planets that are roughly Earth-sized. Perhaps life can arise quickly once a planet's surface cools enough for oceans and lakes to exist. But then on Earth, at least, it took almost four billion years for biology to produce an animal that can build telescopes. I like the Copernican Principle, that we are about average. Maybe somebody, somewhere, developed faster and is millions or tens of millions of years ahead of us. Is that enough for them to develop the tech needed to send expeditions all around the galaxy, and find us? Maybe not.
In coming years, perhaps we will find out. Meanwhile, we have the great task of keeping the one planet we possess in good enough shape that we can survive long enough to be the visitors to someone else.
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