The third planet from the sun, Earth is the only place in the known universe confirmed to host life. With a radius of 3,959 miles, Earth is the fifth largest planet in our solar system ...

The Earth has a layered structure, including the core, mantle and crust. The crust and upper mantle are cracked into large pieces called tectonic plates. These plates move slowly, but can cause ...

A look at the evidence for the Earth being round or spherical. Aristotle’s reasoning is explained. The evidence includes a ship’s hull disappearing first over the horizon, the stars ...