title: What If the Earth Had Two Moons?: And Nine Other Thought-Provoking Speculations on the Solar System
author:  Neil F. Comins 
description: Armchair astronomers and hard SF fans who love a good game of cosmological What If? will find this an entertaining follow-up to physicist Comins's <i>What</i><i>If the Moon Didn't Exist?</i> Here he presents 10 more intellectual puzzles that explore new worlds, and imagine what life there might be like. Each chapter opens with a vivid glimpse of a hypothetical new world, such as in the title scenario, where Earth's gravity captures a second moona scenario that ends in destruction. Equally disastrous would be an Earth with a thicker crustunable to form new volcanoes, hot magma would simply burn through the crust's surface, melting continents and the ocean floor. In another scenario, our solar system forms 15 billion years later than it did, prompting Comins to conjecture that aliens would have more time to traverse great distances to the planet and colonize it. This is a lucid, thoroughly accessible presentation of what might have been that is sure to make this volume as popular as its predecessor. 25 b&amp;w line drawings. <i>(Apr.)</i> <br />Copyright  Reed Business Information, a division of Reed Elsevier Inc. All rights reserved.
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  Dedicated with love to my wife,
  
    
  
  SUZANNE, who is still my girlfriend after all these years.
  
    
  
  To my son JAMES, who asked lots of “What if” questions;
  
    
  
  to my son JOSHUA, who also asks “Why”; and
  
    
  
  to our dear friends WALTER, SANDRA, and ELIAS LYND.
  
    
  
  I hope that the scenarios in this book give us
  
    
  
  glimpses into the environments of other planets in the universe
  
    
  
  and the conditions that may exist on those worlds.
  
    
  
   **Contents**
  
    
  
   _ **Introduction**_
  
   **1\. What If the Earth Had Two Moons? Dimaan, Lluna, and Kuu**
  
   **2\. What If the Earth Were a Moon? Mynoa and Tyran**
  
   **3\. What If the Moon Orbited Backwards? Anillo**
  
   **4\. What If the Earth’s Crust Were Thicker? Dichron**
  
   **5\. What If the Earth Formed Fifteen Billion Years from Now? Futura**
  
   **6\. What If There Were a Counter-Earth, a Planet in Earth’s Orbit on the
  Other Side of the Sun? Dopple I, II, and III**
  
   **7\. What If the Earth Had Formed Elsewhere in the G