Continental drift

Continental drift is the movement of Earth's continents relative to each other over geologic time. When initially proposed as a scientific theory in the early 20th century, the idea that continents could move was widely rejected. However, continental drift has subsequently been extensively validated and is incorporated into the science of plate tectonics, which studies the movement of the continents as they ride on plates of the Earth's lithosphere. The speculation that continents might have "drifted" was first put forward by Abraham Ortelius in 1596. A pioneer of the modern view of mobilism was Austrian geologist Otto Ampferer. The concept was independently and more fully developed by Alfred Wegener in 1912, and expanded into book form with his 1915 publication, Die Entstehung der Kontinente und Ozeane (The Origin of Continents and Oceans). However, at that time his hypothesis was rejected by many, largely because there was no known geological mechanism which could propel such massive movements. In 1931, English geologist Arthur Holmes proposed mantle convection for that mechanism, which is now known to be powered by radioactive decay and primordial heat and a much smaller amount of heat from tidal heating.