Impact!: The Threat of Comets and Asteroids

If, however, you are a person who accepts things scientific, this is your book. Professsor Verschuur is an excellent, lucid, organized writer who does not waste the reader's time with forays into the specculative or ludicrous. Instead he forthrightly presents the overview of, and the detail behind, the genuine, if remote, danger that human society will receive heavy damage, if not outright destruction, from a large impact event. He accurately points out that the remoteness of this eventuality is offset by the magnitude of destruction that will occur if a large impact happens.

I have studied impact phenomena for some years, and this book is the most-fact-filled, well organized book of its genre. It is not only an excellent starting volume for a study of this branch of science, but is a good wake-up call for organizing attempts to meet the danger. The Professor does not patronize his reader, but neither does he presume a level of knowledge beyond the ken of the average well-informed adult.

I recommend the book very highly and would urge anyone interested in this topic to make it a priority purchase. It is the book by which all similar texts should be measured.
July 09, 2002

Dr. Verschuur is a well-respected astronomer, and clearly one of the reasons that he is so highly respected, is his facility for communicating complex information in an understandable way. In this book, he carefully walks the reader through logically presented discussions of the dinosaur-killing asteroid; the tsunamis (huge ocean waves) that would result from an asteroid landing in the sea; the history of the way scientists have thought about the threat of asteroids; and the statistical likelihood that you or I will be slain by an errant asteroid (about 1 in 20,000, which is approximately the same as the chance of dying in a plane crash). While, admittedly, current efforts to prevent plane crashes are stepped up from the norm, doesn't it seem as though we should be taking vastly greater precautions to detect near-Earth asteroids which could destroy civilization???

Dr. Vershuur's account of this threat is very level-headed, and perceptively written. He asks why so many of us have trouble psychologically, conceptualizing the reality of this threat. He also deals, cautiously, with the possibility that ancient legends from around the world may actually tell of asteroid strikes in pre-historic times. This is brave of him to even mention this kind of thing, because it verges on speculation. Scientists are not in the business of irresponsible speculation, after all -- their business is science! They risk grave professional consequences, if they even attempt to discuss such issues. But Dr. Verschuur is very good about alerting the reader to the controversial nature of efforts to extract scientific meaning from the ore of myth. Anyway, he touches on the topic, and it is sometimes interestingly plausible, to my mind at least.

Probably the best thing about this book, is that it helps to alleviate the almost religious terror that the prospect of such collisions produce in most of us. Think of the movie "Armageddon." What a calm, objective, dispassionately conceived title for a movie -- NOT! That movie makes us think about asteroid strikes as a highly infrequent, totally overwhelming event that only Bruce Willis would be able to handle (ha ha). Dr. Verschuur's book, on the other hand, helps us to see that the Earth gets hit CONSTANTLY by asteroids, and it's just a question of understanding the frequency with which we get nailed by the bigger ones.

We learn here that, for example, the Earth gets hit by an asteroid large enough to disrupt a global civilization approximately once every 5,000 years. That's APPROXIMATELY. It can vary by thousands of years. This is just the statistical likelihood, averaged out over millions of years by analyzing the age of craters on Earth, nearby planets, and the moon. We learn that an asteroid with a diameter of 500 meters would probably destroy civilization, and that one that was over 1,000 meters would result in the death of virtually the entire world population of humans. For perspective, the one that finally killed the dinosaurs was about 10,000 meters across. Asteroids that big are rare -- but some are even bigger.

Most asteroids are not quite this threatening, but none are benign. Dr. Vershuur's book really helps us to understand things that more people should be thinking about. My only problem with this book is that I wish it included an appendix of ideas that people should try to implement, as precautionary measures. One example that IS included is the importance of giving money to the (very few) institutions that watch the skies. However, I would like to see a book like this also mention promoting educational initiatives that encourage highly localized electrical power generation options, such as wind energy, in case our global economy is suddenly obliterated. Most importantly, I wish there were a section stressing the importance of learning to grow FOOD in hydroponic, protected, indoor environments, so people would have renewable food supplies if a sudden winter, lasting for years, were brought on by all the dust an asteroid strike would throw up into the sky. No country on Earth has more than a few months of food stored up at any given time. If a major asteroid strike provoked a "nuclear winter" type of scenario, virtually everyone who survived would starve, without precautionary measures.

Still, basically this book is simply fantastic. Definitely two thumbs up.
January 16, 2002