What If the Moon Didn’t Exist? is a book that asks just that– what would Earth be like if the ancient collision that led to our present-day moon never happened and the Earth had no moon? Comins, a professor of astronomy and physics at the University of Maine, also asks what if the moon was closer, what if the Earth was smaller, what if the Earth was tilted like Uranus, among other questions.

This book is a must-have for science fiction writers interested in writing about other planets. Comins follows through on his initial questions in a way that science fiction enthusiasts will appreciate. If the moon didn’t exist, the moon’s tidal pull wouldn’t exist. Due to the lack of that tidal pull, Earth’s day would be 8 hours long, not 24. Which would cause much stronger winds and storms. And the tides would be lower. Which would impede the transition of  life from water to land. And that life would have to adapt to the windy, stormy short days. Would that life develop hearing, with all that wind? Would plants opt for low-surface-area needles instead of broad leaves? Assuming humans developed, how would early man tell time without a lunar cycle? Would this influence man’s scientific development? Comins asks and suggests answers to all of these questions. It’s exciting food for thought, and it made me want to go dream up worlds of my own.

What If the Moon Didn’t Exist? is over twenty years old now. I expect some of the science in it may be outdated (none that I actually noticed, but given the advances in planetary science since 1993, it seems likely). However, the logic the book employs is sound, and I still found it very stimulating. And in researching this post, I discovered two more recent books my Comins: What If the Earth Had Two Moons? written in 2011 and The Hazards of Space Travel: A Tourist’s Guide written in 2007. They seem similar in tenor and I expect to like them too.