The Earth is also known as the blue planet because from space the Earth looks like a blue marble. Salt-water oceans cover about 71% of the earth and the rest is covered by land but even within the land there are lakes and rivers and lots and lots of water

Earth’s Neighbors. Earth has just one Moon. It is the only planet to have just one moon. Earth has lots of spacecraft watching it. There is still a lot we can learn about our home planet. Earth is the third planet from the Sun in our solar system. That

Discover interactions between the earth's four spheres and learn about the processes that shape the earth's surface. Find out how scientists study the earth's crust, mantle and core.