Earth measures more than 12,000 kilometers in diameter, but our direct knowledge of our planet extends only to it outer layer. With indirect observations, such as the study of earthquakes, scientists have been able to establish a model of the interior of the planet.
Earth and the Moon Earth Science, General Science
The History of Earth Earth Science, General Science
The Formation of Earth Earth Science, General Science
Our Knowledge of Geologic Time Earth Science, General Science
Earth Earth Science, General Science
© National Geographic Society 2009
• Terms of Service
• Privacy Policy
Site by Logicbox
& Idea Junction
