The Depth of the Earth: A Journey to the Center of Our Planet.
The Depth of the Earth: A Journey to the Center of Our Planet Beneath our feet lies a world that humanity has barely explored. Although we've mapped distant galaxies and landed spacecraft on other worlds, we have never traveled more than a tiny fraction into Earth's interior. The deepest hole ever drilled—the Kola Superdeep Borehole in Russia—reached about 12.3 kilometers (7.6 miles). Compared to Earth's radius of roughly 6,371 kilometers (3,959 miles), this is less than 0.2% of the journey to the center. So what lies below the surface? Scientists rely on seismic waves, laboratory experiments, and computer models to understand Earth's hidden layers. The Earth's Crust The crust is the thin outer shell where all life exists. It ranges from about 5 to 70 kilometers thick. Oceanic crust is thinner and denser, while continental crust is thicker and older. Despite supporting mountains, forests, cities, and oceans, the crust is surprisingly thin—like the skin of an ap...
