The Big Splat, or How Our Moon Came to Be , Dana Mackenzie Wiley, Hoboken, NJ, 2003. $24.95 (232 pp.). ISBN 0-471-15057-6
I picked up The Big Splat, or How Our Moon Came to Be, and like scientists often do when examining a popular book about “their” science (particularly a book with a campy title), I scrutinized it with regard to objective metrics—truthful homage to the present thinking, for example. But I do acknowledge a certain paradox that drives science in society forward, a balancing act that can turn a book on science into a bestseller and pique the curiosity of a taxpayer. The crux is that we want our science to be popular, but we know there is no shortcut to the forefront of research. The chemistry, the math, and the physics get in the way of a splendid view. And so we simplify—we crop the photo, as it were. Is that wrong?
An alternative to science hype is science history, which can have its own share of compromises. To have history succeed as narrative, an author reduces historical facts until the past makes sense to those who were not there. Because reality is fractal or holographic, as one can learn in popular science books, an author might use narrative art to provide the missing dimensions to embellish historical characters and events. This too is perhaps a white lie.
The Big Splat is an examination of the modern theory that an object the size of Mars collided with the early Earth to create the Moon, but the book reaches back to the very foundations of human thinking about how the Moon came to be. In writing the book, Dana Mackenzie took on the added challenge of treating the ancient past and the modern scientific era alike, both thematically and descriptively. The historical present—in this case, the shared experience of veterans of lunar science—can never be as romantic as the historical past. For one thing, an author can’t make up intimate detail regarding living scientists; dead scientists, on the other hand, seldom complain. More applicable to Mackenzie’s endeavor is that authors have little access to intimate letters between active scientists, but one can find plenty of vivid dialogue in the archives of long-dead scientists. Replace the names in the following passage found in chapter 3 of the book with your favorite pair of active academicians, and you’ll understand what I mean: “By the time they got to Kepler’s place, Wackher was ready to burst.” The past becomes lively, making the present seem stale. In this particular kind of combined narrative, the past is built up to about a few choice morsels, and the present must be filmed in soft focus to blend in with, for example, scenes of Galileo peering through his first telescope or of George Darwin writing breathless letters to his proud father, Charles.
Mackenzie has chosen to spin a proper yarn, and I commend him for taking this difficult, daring approach. His resulting narrative is going to be a lot of fun for a wide variety of readers. The Big Splat will be popular at bookstores, in airport shops, and on the shelves of academic and public libraries because it provides an appropriate scientific snapshot of a unique period in human history when we understood how the Moon came to be. It is obvious from his writing that Mackenzie, a researcher in mathematics, has studied many of the major papers to come out concerning the origin of the Moon. He is well versed in the nuances, and the result is a more than adequate balance of historical and scientific accuracy and gifted storytelling.
The Big Splat begins with the ancients, proceeds to the Renaissance and the continental philosophers, and concludes with the Age of Hartmann. The book portrays lunar science as a collective endeavor, but William Hartmann wins the crown not only for boldly articulating the giant-impact idea in the mid-1970s (with Alastair Cameron, Donald Davis, and William Ward as early champions) but also for conveying the idea through his excellent writings and paintings, one of which is featured on the book’s cover. This Renaissance humanist is in good company in the pages of Mackenzie’s book.
But conversely, there is an unfortunate reduction of subtleties, and two principal characters are missing entirely. Much tribute is paid to the smooth particle hydrocode on which virtually every long-term simulation of the giant impact has been based, but no mention is made of the code’s author, Swiss planetary physicist Willy Benz, who performed the first “big splat” simulations. Another missing presence is George Wetherill, whose science writings in the 1970s and early 1980s compelled scientists to understand that giant planetary cataclysms were the norm during the final stage of terrestrial planet accretion.
The book’s end matter is extensive and well thought out; it begins with a comprehensive final overview of the latest understanding of the big splat. (Are we doomed now to live with that phrase?) The appendix is valuable to the modern instructor because it provides clear rebuttals to recently televised “accounts” (such as Conspiracy Theory: Did We Land on the Moon? aired by the Fox network in 2001) that humans never made the incredible voyage to the Moon. Mackenzie provides an excellent glossary and a comprehensive scientific and historical bibliography whose choices make sense. The book is replete with diagrams, tables, and schematics. The publisher should consider adding a CD with pictures, animations, and PDF files of the major papers from the age of reason to the present.
Mackenzie does not target his book at scientists, although he does not hold back on the science. (I learned some new aspects of extinct radionuclide systematics, for example.) The Big Splat is entertaining, intellectually satisfying, and a good read, and it is certainly not short on factual and physical detail. Seeing the modern lunar-origins community sharing pages alongside Pierre-Simon Laplace, Johannes Kepler, Edouard-Albert Roche, and Johannes Matthaeus Wackher von Wackenfels, one gets the feeling we may all be part of history. If the tale is somewhat better in the telling, so be it.
Erik Asphaug is a planetary scientist at the University of California, Santa Cruz, who studies asteroids and comets, their geologic makeup and evolution, their impacts into planets, and their relation to the origin of solar systems. He also studies impact craters, asteroid hazards, and giant collisions.
