The man who said continents move was right, and was laughed at for decades.
In 1912 Alfred Wegener argued that the continents had once been joined in a single landmass and had drifted apart. Most geologists rejected it: nobody could say what force could push a continent. Half a century later, maps of the seafloor proved him right.
People had long noticed that South America and Africa look as if they would slot together. The mapmaker Abraham Ortelius suggested in 1596 that the Americas had been torn away from Europe and Africa. But it was the German scientist Alfred Wegener who built the idea into a full theory, presenting it on 6 January 1912 and expanding it in his 1915 book The Origin of Continents and Oceans. He proposed an ancient supercontinent, Pangaea, and coined the phrase 'continental drift'.
His evidence was broad. Fossils of the freshwater reptile Mesosaurus appear in both Brazil and South Africa; the land reptile Lystrosaurus turns up in rocks of the same age in Africa, India and Antarctica. Traces of ancient glaciers are scattered across southern continents, including India and Australia, in patterns that make sense only if those lands were once together near the South Pole.
The establishment was not persuaded. Wegener had no convincing mechanism: his suggestions, involving Earth's rotation, were far too weak. His estimate of drift speed, about 250 centimetres a year, was wildly high; the real figure for the Atlantic is about 2.5. He was also not a geologist. As late as the 1940s, David Attenborough was told by a lecturer that the idea was 'moonshine'. Wegener did not live to see it accepted. Arthur Holmes proposed in 1928, and again in 1931, that heat-driven currents in the mantle could carry the crust, but the idea stayed unfashionable.
The breakthrough came from the ocean floor. After the Second World War, surveys revealed mid-ocean ridges where new seafloor is created, and magnetic stripes in the rock recording that spreading. Marie Tharp's maps helped make the case. By the late 1960s continental drift had been absorbed into plate tectonics. Today GPS measures it directly: one receiver in Maui moved well over half a metre in 14 years.
Source: Wikipedia — Continental drift · Text summarised from Wikipedia (CC BY-SA 4.0)
