Before the advent of plate tectonics, however, some people already believed that the present-day continents were the fragmented pieces of preexisting larger landmasses ("supercontinents").
The continents are consistently moving away from each other, but this isn't any new news. The land we live on has been separating for more than 300 million years. Caused by the never-ending curring magma underneath the earth's crust, the continents continue to slowly drift away from each other.
The theory of plate tectonics has done for geology what Charles Darwin's theory of evolution did for biology. It provides geology with a comprehensive theory that explains "how the Earth works."
Hot rocks rise heated by the Earth's core. Near the surface, the crust spreads. It goes sideways and begins to lose heat then the cooler rock sinks back down. By this the Earth's crust is slowly dragged apart.