THE BOOK REVIEW

BY HARALD DAHLE

I was working on this impact simulation model some ten years ago together with Galen Gisler the scientist at Los Alamos National Laboratories who had designed the computer simulation. You can watch the simulation here. The asteroid is calculated to be 200 meter in diameter, arriving at the speed of 20Km/second at a ninety degree angle to the ocean surface. 

The impact created a humongous barrel of ocean water with a height between 3500 meter and 4500 meter. If this had happened over land and at 50 degree incoming angle, it would have been the heat from the Asteroid that would have been the killer in the first instance.

Our simulation proved that the asteroid made a significant scar in the 7Km thick basalt crust. In real-time the impact was happening so fast that it was beyond human comprehension, thus the slow motion Los Alamos computer simulation was of great value to us.

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Los Alamos Asteroid Impact in the Ocean Simulation (Petrofilm)

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Asteroid Rain Evaporates Two Cities in a Heat Flash (Petrofilm)

Due to significant increases in number crunching capacity in today's super computers at Los Alamos, the simulations they make now are of considerable better quality than the simulation we worked with. The need to understand Comet and Asteroid impacts better has resulted in a cascade of individual scientific papers over the paste decade.

Now, for the first time comes a 1300 pages Bible of a book, dedicated solely to "Hazards due to Comets and Asteroids". The eight chapters are as following with the corresponding page number on the right side The article sources take up considerable space and is not counted for here, thus the lack of chronological page numbering.



Tom Gehrels is the Editor of the book. In the Preface he writes, "It is a special pleasure to present this book as the 24th in the Space Science Series. This volume documents the be- ginning of a new discipline, namely the detection and mitigation of hazardous asteroids and comets."

The content is based on at least four workshops at San Juan Capistrano April/May 1991, Los Alamos National Laboratories in 1992, Tucson in January 1993 and at Erice in May 1993 There was an even earlier meeting, in June 1981 at Aspen Colorado.

The Book content

Part 1 Smaller Bodies 3-93,

Part 2 Searches, Orbit Determination, and Predictionn127-259,

Part 3 NEO Populations and Impact Flux 285-479,

Part 4 Physical Properties 537-635,

Part 5 Space Exploration 651-683,

Part 6 Effect of NEO Impact 711-879,

Part 7 Hazard Mitigation 897-1111,

Part 8 Considerations for Future Work 1135-1225,

Part 9 Appendix: Earth Crossing Asteroids

Illustrations bellow are from the Los Alamos Asteroid Impact Simulation G. Gisler/H. Dahle

The amount of work that went into creating this book is estimated to be at least US Dollar 1.6 Million in terms of salaries and operations of the participants. The production was supported by the Ballistic Missile Defense Organization, the Los Alamos National laboratory, the University of Arizona, and the University of Arizona Press. I am glad that Dr.Jay Melosh, University Distinguished Professor at University of Purdue has been included in this volume.

As an example from the book I have chosen Eugene H. Levy of the University of Arizona. He concludes, "I believe that we scientists have a crucial role to play, a critical responsibility to fulfill. It is very important that the informed community of scientists participate in defining the realistic extent of the hazard and defining the sensible steps, if any, to take in response.

It is also important for the scientific community to help weigh this hazard against the risk and dangers associated with conceivable protective measures. The scientific community can gather the knowledge and develop the judgement necessary for informed decision-making and wisdom in this area." I have read the book Hazards due to Comets & Asteroids and recommend it highly, five well deserved stars!

Pictures of impact craters bellow are renderings by Harald Jan Dahle, software Terragen



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Using Mathemathical Expressions to create Planetary Movements (Petrofilm)

Illustration of the Epsilon Eridani System