Imagine a world where the fate of nations is swayed by distant planets, where cosmic events ripple through the fabric of our daily lives, and where the survival of life itself hinges on our understanding of these celestial forces. This world is our own: planet Earth.Our solar system is a dynamic arena where asteroids veer off course and solar winds hurl charged particles across billions of miles of space. Yet, we seldom consider how these colossal events impact our fragile, blue planet. In Ripples on the Cosmic Ocean, Dagomar Degroot masterfully traces the surprising threads linking human endeavour to the rest of the solar system. He reveals how the variability in planetary environments has shaped geopolitics, spurred scientific and cultural innovation, and inspired new ideas about the emergence and ultimate fate of life. Martian dust storms altered the trajectory of the Cold War and inspired fantastical stories about alien civilisations. Comet impacts on Jupiter led to the first planetary defence strategy. And volcanic eruptions spewed sulfuric acid into Venus’ 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. Yet, they may also hold the key to slowing the destruction of environments on Earth. Ripples on the Cosmic Ocean challenges us to develop an interplanetary environmentalism across a vast mosaic of entangled worlds, urging us to consider the profound connections that bind us to the cosmos and to each other.