€œWhat if?€ questions have always stimulated people to think in new ways. What if the Earth Had Two Moons leads us on a fascinating 10 world journey exploring what the Earth would be like if conditions in the universe were slightly different. The answer: Earth would be different, often in ways that would surprise us. The title chapter, for example, gives us a second moon orbiting closer to Earth than the one we have now. The night sky is a lot brighter, but not forever. Eventually the moons collide, with one more-massive moon emerging after a period during which Earth has a Saturn-like ring. The scenarios also shed new light on the burgeoning search for life on planets orbiting other stars.

Appealing to adult and young adult alike, this book follows on the author€s previous bestseller, What if the Moon Didn€t Exist?, with completely new scenarios backed by the latest astronomical research.