Earth's outer layers can wander over its core, which causes so-called true polar wander. A model has figured out how Earth's bulge may cause the layers to snap back into place.

The mantle, or middle layer, makes up 84% of Earth's volume, and the innermost layer, the core, makes up the final 15%, according to the University of Illinois Urbana-Champaign.

T here's a lot more to Earth than meets the eye. Far from being just a roundish rock barreling through space, our planet is composed of several layers held together by intense forces of gravity.

Atlanta students learn how to protect planet during Earth Day event at Ralph Bunche Middle School. April 22, 2025 at 4:54 pm EDT. April 22, 2025 at 4:54 pm EDT.