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My first scientific love was astronomy, undoubtedly spurred by visits to the Adler Planetarium in Chicago, where I grew up. Although I eventually chose chemistry over astronomy as a profession, my affection for the subject has never waned. How can one not get excited by relativity, black holes, the big bang, the background microwave radiation, dark matter, dark energy, and so many other things? It still is exhilarating to look up in the sky before dawn and see the constellation Orion, the hunter, whose red giant star, Betelgeuse, is so large that if it were at the center of our solar system, Earth would be in its interior.
Although physics is central to understanding the makeup and history of the universe, chemistry also plays a very prominent role. The stellar synthesis of atoms in the interiors of stars and supernovae, after all, ultimately led to simple and then complex life by as yet poorly understood pathways. The story of this complex evolution from atoms to life is described in Andrew Shaw’s very readable textbook, Astrochemistry—From Astronomy to Astrobiology.
One cannot, of course, begin a discussion of astrochemistry without first describing what is known about the origin of the universe. At its beginning the universe was unimaginably hot and dense and expanded rapidly. When the expansion slowed sufficiently, the hydrogen and traces of other low atomic number atoms, which had been created in this cataclysm, coalesced under the influence of gravity to form galaxies and first generation stars where nucleosynthesis generated atoms with atomic numbers through iron. These stars eventually ran out of fuel. Those that were several times more massive than our sun succumbed to gravity at their death, producing spectacular explosions called supernovae that completed the synthesis of the remaining elements. These early supernovae spewed out enormous quantities of atoms, providing material for second generation stars such as our sun and its solar system of planets, moons, asteroids, and comets. These bodies as well as giant molecular clouds are the nurseries for the synthesis of complex molecules. Close to one hundred molecules have been identified to date in these enormous clouds, for example. Even though I thought I knew quite a bit about these topics, I learned much more on reading this book. I think the reader will be amazed at how much information one can learn about the size, density, and surface temperature of a star by application of basic principles of physics and physical chemistry. Identifying atoms in stars and the hundred or so molecules in gaseous clouds (the building blocks of life) requires a detailed knowledge of spectroscopy, a subject that is clearly and extensively discussed in the book.
As the origin of life is a major theme of the text, the author spends considerable productive time describing what scientists believe to be the exogenous and endogenous synthesis of the basic molecules of life in the pre-biotic world and how these may have coalesced into self-replicating primitive cells. The author devotes a couple of speculative pages on the origin of homochirality, a topic of current interest to me (1). This is perhaps the most enigmatic feature of the poorly understood mechanism by which life began. The author loses his way a bit in his discussion of homochirality. He confuses, for example, D and L, which refer to the absolute configuration of amino acids and sugars, with d and l, which refer to the sign of rotation an optically active molecule yields in a polarimeter.
The book is arranged into 10 chapters on a variety of topics only a few of which I alluded to above. The final chapter, for instance, deals with the Saturnian moon, Titan, where some astronomers speculate life may exist. Because this is a textbook, the author has been attentive to the needs of students and has included in each chapter a large number of clear drawings, figures, pictures, equations, and a large set of interesting problems, some of which are answered in one of several appendices at the end of the book. There are in addition a beautiful set of color plates in the center of the book, an extensive glossary of terms, and a thorough bibliography of books and papers for those who wish to explore topics in greater detail. I found the index a bit sketchy, but with a little effort I always found what I was seeking.
I read the book for enjoyment, and I am sure others will do this as well, but it can stand on its own for a course in astrochemistry or pre-biotic chemistry. The textbook will also make a nice supplement to undergraduate courses in organic chemistry and in particular physical chemistry.
Literature Cited
- Compton, R. N.; Pagni, R. M. The Chirality of Biomolecules. In Adv. Atom. Mol. Phys. 2002, 48, 219–261.
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