I spent years preparing to dive into the deepest place on earth. Only a handful of people have traveled into the depths of the Mariana Trench, nearly 7 miles below the ocean surface. As a geologist ...

About 71% of the Earth’s surface is water-covered, and the oceans hold about 96.5% of all Earth’s water. Water also exists in the air as water vapor, in rivers and lakes, in icecaps and glaciers, in ...