Origins and Importance of Water

Water is so uniquely favorable to life as we know it, it is hard to imagine life without it. Where did it come from, this planetary wrap of fluid, this liquidy bower? A standard story is that the heat of the young Earth drove hydrogen and oxygen out of chemical combination in minerals like mica, and these atoms then combined to form water. Four billion years ago the planet was mostly molten, heated by radioactivity and the violence of its formation—a vast spherical volcano—and the newly f...