A Scientific American, Nautilus, and New Scientist Best Book of the Year The untold story of how environmental change throughout the cosmos shaped five hundred years of human civilization. Our solar system is a dynamic arena where asteroids careen off course and solar winds hurl charged particles across billions of miles of space. Yet we seldom consider how these events, so immense in scale, influence our fragile blue planet: Earth. In Ripples on the Cosmic Ocean, Dagomar Degroot traces the surprising threads linking human endeavor to the rest of the solar system. He reveals how variability in planetary environments has shaped geopolitics, spurred scientific and cultural innovation, and encouraged new ideas about the emergence and fate of life. Martian dust storms altered the trajectory of the Cold War and inspired fantastical stories about alien civilizations. Comet impacts on Jupiter led to the first planetary defense strategy. And volcanic eruptions spewed sulfuric acid into Venus's atmosphere, exposing the existential risks of climate change at home. As we stand on the brink of a new era of space settlement, cosmic environments are becoming increasingly vulnerable to human activity. They may also hold the key to slowing the destruction of environments on Earth. Ripples on the Cosmic Ocean urges us to develop an interplanetary environmentalism across a vast mosaic of entangled worlds and to consider the profound connections that bind us to the cosmos and each other.