Inside Planet Earth: Introduction to Different Ideas

About the inside of Planet Earth, an introduction to the different ideas.

Inside the Good Earth: What's Going On under Our Feet?

The earth on which man stands has been as much a mystery to him as the heavens, and reaching its core has proved more difficult than reaching the stars. What lies within the earth? Folklore and science, ancient and modern, have tried to answer that question. One idea about the interior of the earth has endured: that it is hollow.