Well, Earth is the [planet](planet.md) we live on. It is the third planet from the [Sun](sun.md) of our Solar system which itself is part of the [Milky Way](milky_way.md) [galaxy](galaxy.md), [Universe](universe.md). So far it is the only known place to have [life](life.md).
Earth is the third planet from the [Sun](sun.md) and the fifth largest in the Solar System, it has an ellipsoid shape. It has formed from space dust nearly 5 billion years ago during the formation of our Solar System. Soon after its formation it was struck by a Mars-sized body, called Theia, which led to the formation of the [Moon](moon.md), Earth's only natural satellite. It's only by [curious](interesting.md) happenstance that the Moon is currently of the same size in the sky as the Sun, allowing perfect eclipses -- nonetheless the Moon is constantly getting further away from us and will be getting visually smaller. Earth has a hot core, an atmosphere and a magnetic field, its surface is mostly (71%) covered by water. Evidence suggests that [life](life.md) appeared on Earth some 3 and a half billion years ago. Scientists predict that the Earth will be devoured by the Sun that will expand its radius significantly some 7 and a half billion years from now.
