Fire on Earth: Doomsday, Dinosaurs, and Humankind - Softcover

Here is an able summary of the growing body of evidence that Earth has sustained a number of collisions with various large objects from space. John Gribbin (In the Beginning, 1993, etc.) and his wife are a versatile British team of popular-science writers, and the story of asteroid collisions calls on their wide range of scientific knowledge. The discovery of high concentrations of the element iridium (rare on Earth, but common in meteors) in the geological strata marking the end of the Cretaceous Period led a team of chemists and geologists to the conclusion that a large meteor impact had occurred at that time, probably causing the death of the dinosaurs. This theory initially met with widespread skepticism, but the evidence for it has continued to accumulate. The authors summarize the Tunguska event, a probable meteor impact in Siberia in 1908, and another that took place in the same region in 1947. There have been a few spectacular near- misses--one fireball seen over Montana in 1972, another over the Pacific in 1994. Impact craters on the moon and other planets testify that over geological time spans these events are far from rare. And the collision of Comet Shoemaker-Levy with Jupiter made it abundantly clear how powerful such a collision would be. The volume of space around the Earth as well as beyond our solar system contains a large number of comets, meteors, and small asteroids. Large objects, the size of the dinosaur killer, seem to arrive with a periodicity on the order of 30 million years. The Gribbins also discuss the possibility of a periodic swarm of smaller objects every few thousand years, causing widespread damage and disrupting civilization. Finally, they discuss various plans being made to detect and possibly deflect an incoming object--concluding that such efforts are unlikely to be of value in the foreseeable future. A well-written and comprehensive discussion of a sobering but inevitably fascinating subject. -- Copyright ©1996, Kirkus Associates, LP. All rights reserved.

A crater discovered in Mexico's Yucatan Peninsula in 1978, and intensively investigated in 1990, may provide the "smoking gun" confirming that the extinction of the dinosaurs was caused by a meteorite that smashed into Earth 65 million years ago, wiping out 70% of all plant and animal species. The Gribbins, popular science writers, consider the evidence for this theory overwhelming. Collisions with comets, scientists now believe, have resulted in mass extinctions on Earth every 26 to 30 million years. Lesser cosmic impacts, the Gribbins hypothesize, shaped the evolution of human civilization by triggering ice ages. The Tunguska explosion of 1908, which produced a devastating fireball in Siberia that destroyed forests and caused worldwide tremors, was the result of an asteroid or meteor, they believe. More speculative is their proposal that a cataclysmic collision triggered the collapse of Roman Britain around A.D 500. Fragments of the Shoemaker-Levy comet rammed into Jupiter in 1994. To monitor the possibility of similar catastrophes on our planet, the Gribbins strongly endorse NASA's proposed Spaceguard Survey, a scheme to identify threatening asteroids and comets using a network of as-yet-unbuilt telescopes. Free of sensationalism, this is popular science writing at its most lucid and entertaining.
Copyright 1996 Reed Business Information, Inc.