Earth

Earth whose Latin name is Tellus is the third planet in the solar system in terms of distance from the Sun, and the fifth largest. It is also the largest of its planetary system's terrestrial planets, making it the largest solid body in the solar system, and it is the only place in the universe known to support life. The Earth was formed around 4.57 billion years ago and its largest natural satellite, the Moon, was orbiting it shortly thereafter, around 4.533 billion years ago.

Since it formed, the Earth has changed through geological and biological processes that have hidden traces of the original conditions. The outer surface is divided into several tectonic plates that gradually migrate across the surface over geologic time spans. The interior of the planet remains active, with a thick layer of convecting yet solid Earth mantle and an iron core that generates a magnetic field. The atmospheric conditions have been significantly altered by the presence of life forms, which create an ecological balance that modifies the surface conditions. About 71% of the surface is covered in salt water oceans, and the remainder consists of continents and islands.