There'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. Our ...

Earth's crust ranges from 5 to 70 kilometers in thickness and serves as the planet's outermost layer. This thin shell represents less than one percent of Earth's total mass, yet it's the only layer we ...

When I was a kid, I liked to dig holes in my backyard in Cincinnati, Ohio. My grandfather joked that if I kept digging, I would end up in China. In fact, if I had been able to dig straight through the ...