- Earth is the third planet from the sun and the densest major body in the solar system. 71% of Earth's surface is covered with water and it is the only planet where water can exist as a liquid on the surface. - Earth's atmosphere is 77% nitrogen, 21% oxygen, with traces of other gases. The interaction between Earth and the Moon is slowing Earth's rotation over time. - There are debates around whether there are six or seven continents, depending on whether Europe and Asia are considered separate or combined as Eurasia. The continents are Antarctica, Australia, Africa, North America, South America, Asia, and Europe.