Scientists now know that the Earth's continents are in constant motion, driven by the movement of tectonic plates. This process, known as continental drift, was first proposed by Alfred Wegener in the early 20th century, but was rejected by many scientists at the time.

One of the main reasons Wegener's theory was rejected was because there was no known mechanism to explain how the continents could move across the Earth's surface. However, in the 1960s, the theory of plate tectonics was developed, which finally provided a credible explanation for Wegener's ideas.

Plate tectonics explains that the Earth's crust is made up of a number of tectonic plates that are constantly moving over the Earth's mantle. The movement of these plates is driven by convection currents within the mantle, which is the layer of rock beneath the Earth's crust.

The theory of plate tectonics has revolutionized our understanding of the Earth and its history, and it has provided a wealth of evidence to support Wegener's theory of continental drift. For example, scientists have now found that the rocks on different continents fit together like jigsaw puzzle pieces, and that the distribution of fossils on different continents supports the idea that the continents were once connected.

Today, continental drift is a well-established fact, and it is essential to our understanding of the Earth's history and dynamics.