9781422285589

11 Chapter One: Formation and Location

The western hemisphere of Earth, photographed from space. Photographs like this one lead to the Earth being nicknamed “the Big Blue Marble” because of its vast oceans.

A Unique Planet In many ways, the planet Earth is in a class of its own. For one thing, no other planet in our solar system has vast oceans of water that sustain life. Earth has so much ocean water that if you were to mold the planet’s surface it into a smooth sphere with no mountains or valleys, that sphere would be completely covered by seawater nearly 8,200 feet (2,500 meters) deep.