Continental drift

Continental drift is a well-supported scientific theory that explains how Earth's continents move slowly over very long periods of geologic time. This idea began in the early 1900s when scientists noticed that the shapes of continents like Africa and South America looked like they could fit together like puzzle pieces.

The theory was first suggested by a mapmaker named Abraham Ortelius in 1596, but it was developed much more fully by a scientist named Alfred Wegener in 1912. Wegener’s book, The Origin of Continents and Oceans, explained how continents might once have been joined together and then drifted apart. At the time, many other scientists did not accept his idea because they did not know what could make such huge movements happen.

Later, another scientist, Arthur Holmes, suggested that heat deep inside the Earth, called mantle convection, could be the driving force. Today we know this theory is part of a bigger science called plate tectonics, which helps us understand many things about our planet, from earthquakes to the formation of mountains.

History

Further information: Timeline of the development of tectonophysics (before 1954)

Abraham Ortelius, Alfred Russel Wallace, Eduard Suess, and others noticed that the shapes of continents on opposite sides of the Atlantic Ocean seemed to fit together. They wondered if the continents had once been connected.

In 1912, Alfred Wegener proposed the theory of continental drift. He suggested that all the continents were once part of a single landmass called Pangaea, which later broke apart and moved to their current positions. Wegener gathered evidence from fossils, rock formations, and glaciers to support his idea.

At first, many scientists did not accept Wegener’s theory because he could not explain how the continents moved. It wasn’t until the 1960s, with the development of the theory of plate tectonics, that Wegener’s ideas were fully accepted. Plate tectonics explains that the Earth’s crust is made of moving plates, and it is this movement that causes continents to drift over time.