Earth has a hot core that heats the surrounding mantle, which carries that heat up to the planet’s lithosphere. The heat is then lost to space, cooling the uppermost region of the mantle. This mantle convection drives tectonic processes on the surface, keeping a patchwork of mobile plates in motion. Venus, which is Earth’s twin in size, doesn’t have tectonic plates, so how the planet loses its heat and what processes shape its surface have been...
