How were the seven continents formed?
This is a rather long story that basically spans most of Earth’s history. In order to understand where the continents came from we have to go back to about the beginning. As our solar system formed rocky and metallic asteroid began to collect in the part of the solar nebula to for Earth. As these bodies came together to form our planet, the heat of their impacts eventually cause Earth’s surface to melt. This created a magma ocean. As this magma ocean began to cool Earth developed a crust that was probably made mostly of rock that were similar in composition to basaltic lava. (At this stage in its history, Earth probably looked very much like the planet in Star Wars: Revenge of the Sith where Obiwan and Darth Vader had their climactic battle.) As this crust and the underlying mantle cooled we eventually say the formation of the lithosphere. (This is a layer of the Earth that contains all of the crust and about the upper 100 km of the mantle.) As this layer cooled it got denser. Eventual
