"What if?" questions stimulate people to think in new ways, to refresh old ideas, and to make new discoveries. In What If the Earth Had Two Moons, Neil Comins l

An astonishing exploration of planet formation and the origins of life by one of the world’s most innovative planetary geologists. In 1959, the Soviet probe L

Demonstrates how ten hypothetical situations would affect our planet and life on it. Topics include: what if the moon didn't exist, what if earth were tilted li

An astronomer and author explores ten examples of what Earth would be like if conditions in the universe were slightly altered, in a fascinating journey into sc

What if Earth had several moons or massive rings like Saturn? What if the Sun were but one star in a double-star or triple-star system? What if Earth were the o