A SPHERICAL ORB out Earth is a spherical orb orbiting the Sun. The planet is namic system that has been developing for 4.5 billion years, and we have been present on the Earth for only the last few hundred thousand years. Over the history of humanity, we have used a variety of scientific techniques, thoughtful insights, and intuitive leaps to learn about what exists in the interior of Earth. Often, these intuitive leaps were remarkably incorrect, and sometimes, the results from the scientific work were completely unexpected Let's take a journey from the dark, liquid core of the planet outwards to the beautiful surface that we call home We'll explore what humans have learned about the Earth's interior and how this knowledge was gained. Along the way, we'll check in on the chemistry and composition of the rocks, and discover the dynamic changes that are occurring in these unimaginably strange places their We'll meet some of the geologists that have devoted thoughts and energies to the study of the Earth, and we'll ponder some of the great unknowns of geology on Earth and the other planets in our universe