Fascinating story of a great scientific discovery, 2003-09-11
It's interesting to see that this book is now being used as a text in high school and even junior high school science classes in the US. I had a great laugh from the reaction of a young reader who wrote that it was "boring" and that "Innocent eight graders shouldn't have to read this stuff"!Ah, yes. Innocence. But 14-year-olds aside, this is a fascinating and delightful story of scientific discovery and triumph second to none. It can be compared to James D. Watson's The Double Helix: A Personal Account of the Discovery of the Structure of DNA, both in terms of the importance of the discovery and for bringing to the reader some of the excitement and adventure of the quest. It is not, however, as the title might imply, the reading equivalent of watching a Stephen Spielberg movie! And perhaps we can be thankful for that.
T. Rex and the Crater of Doom is the story of one of the great scientific discoveries of the twentieth century. Prior to Alvarez's work, it was not known what had caused the extinction of the dinosaurs. Volcanism, disease, climate change, etc., were put forward as possibilities. But in1970 Alvarez began to believe that a large meteor or a comet had struck the earth with enormous force causing the extinctions. But how to prove it? At first it wasn't even imagined how a meteor could bring about such a catastrophe; but gradually it was seen that the debris thrown into the atmosphere by the force of impact would encircle the earth and block out the rays of the sun for months or even years at a time, thereby killing off plants both on the land and in the sea, thereby collapsing the food chain and starving the dinosaurs and most other creatures.
This was the breakthrough idea, and an exciting idea it was. Of course there was great resistance, as there always is in science when established opinions are threatened, and Alvarez and his team of scientists had to fight mightily against the orthodoxy of uniformitarianism which had held sway in geology and paleontology since the time of Charles Lyell. It wasn't until twelve years later in 1992 that Alvarez's theory finally found general acceptance in the scientific community.
One of Alvarez's purposes in this book is to show a general readership how scientific discoveries are made and confirmed. His tone is generous and he goes out of his way (unlike Watson in The Double Helix) to give credit to everyone involved. He makes it clear that the work was a shared enterprise. One thing that stood out in my mind was the central contribution from Alverez's father, Luis, a physicist who unfortunately died before the theory could be confirmed.
Alvarez does however allow himself an occasional sarcasm vis-a-vis the old order. Characterizing the "conventional geologic opinion" on the formation of craters like the Meteor Crater in Arizona as due to "mysterious explosions that occurred at random times and places for no evident reason," he appends this observation: "In retrospect this causeless mechanism...is indistinguishable from magic, but at the time many geologists considered it preferable to catastrophic impacts." (p 76)
Science is especially subject to the braking effect of established opinion because it is extremely difficult for anybody to allow that the established beliefs of their entire professional career can suddenly be overturned. All your life you believed one thing and one day you wake up and some whippersnapper has overturned the entire edifice! That is hard to take, and so entrenched opinion wars against new discovery. But that is as it should be since extraordinary claims do indeed require extraordinary proof.
Therefore, just as "the course of true love never did run smooth" (Shakespeare), so it is with science. Alvarez recounts an early misdirection in the quest when it was thought that they had found plutonium-244 in the KT boundary clay, possibly indicating a nearby supernova explosion 65 million years ago. He and Frank Asaro took their discovery to Earl Hyde, a nuclear chemist who listened patiently to the details and then said, "Do it all over again." This was very good advice because when they did it all over again they found they had erred: there was no plutonium-244 in the clay samples! (p. 74)
After reading this book we are left with an intriguing question: what was the role of volcanism, not only in the KT extinction but in the Permian-Triassic as well? Alvarez hints that there must be more than coincidence involved in the fact that during both extinctions there is indisputable evidence of vast lava flows. Does a truly monstrous impact somehow trigger volcanic eruptions? An "intriguing mystery" is what Alvarez calls it. (pp. 143-144)
This book should be read in conjunction with David M. Raup's The Nemesis Affair: A Story of the Death of Dinosaurs and the Ways of Science which covers some of the same ground (especially the fight against established opinion) while claiming a 26-million year periodicity for impact extinctions caused by Oort Cloud perturbations from a hypothetical companion star, dubbed "Nemesis."