Earth time and again known as the Earth, Terra, the World or Planet Earth is the third planet away from the Sun, and is the fifth biggest planet in the solar system. It is also the largest of its terrestrial system's global planets, making it the largest solid body in the solar system, and it is the only position in the universe recognized to humans to support life. It is as well the densest planet in the lunar system. The Earth was shaped around 4.57 billion years ago and its natural satellite, the Moon, was orbiting it soon thereafter, around 4.53 billion years ago.
The outer surface is divided into several tectonic plates that slowly travel across the surface over geologic time spans. The center of the planet remains active, with a thick layer of convicting yet solid layer and an iron core that generates a magnetic field. Its atmospheric conditions have been noticeably altered by the presence of life forms, which make an ecological balance that modifies the surface situation. Concerning 71% of the surface is covered in salt-water oceans, and the remaining contains continents and islands.