What If the Moon Didn't Exist: Voyages to Earths That Might Have Been

Comins, an astronomy professor at the University of Maine, inverts the anthropic principle of cosmology--suggesting that the universe evolved in order to produce life as we know it--and envisions an array of biosystems that would likely have occurred if particular events had not taken place. The first of these, after describing how our moon was formed from the impact of an asteroid on the molten earth, posits the characteristics of life that might have evolved without the moon's influence, e.g., diminished tidal changes would have reduced the number of species. The first few of these speculations are intriguing; then the device becomes boring, relying on a kind of ``wow!'' response that readers of popular science will find hard to sustain. Many of these scenarios are necessarily vague. Posing a supernova explosion only 50 light years away, Comins notes that food-chain relationships would break down and nature would have to ``rebuild'' the ``hierarchies of life.'' BOMC and QPB alternates; Newbridge Book Club dual selection. (Nov.)