Planet Earth

Earth, also called the world (and, less frequently, Gaia or Terra) is the third planet from the Sun, the largest of the Solar System’s four terrestrial planets. Earth’s biodiversity has expanded continually except when interrupted by mass extinctions. Earth’s population is divided among about two hundred sovereign states which interact through diplomacy, conflict, travel, and trade. Seventy-one percent of Earth’s surface is covered with water, with the remainder consisting of continents and islands that together have many lakes and other sources of water. Earth’s polar regions are mostly covered with ice.

Earth gravitationally interacts with other objects in space, especially the Sun and the Moon. During one orbit around the Sun, Earth rotates about its own axis times creating 366 solar days or one year.