User:Tankey6/TWA/Earth





=Earth= The Earth is the third planet from the Sun. It is one of the four terrestrial planets in our Solar System. This means most of its mass is solid. The other three are Mercury, Mars, and Venus. The Earth is also called the Blue Planet, Planet Earth, and Terra.

The Earth is the only planet with life that we know of and is home to millions of species of plants and animals, including humans. Earth has many places that are suitable for humans to live; although, some areas of the planet can be dangerous for humans or uninhabitable.

The Earth has 4 layers: The Crust, the mantle, the outer core, and the inner core. On the crust, there are 4, 5, 6, or 7 continents depending on how people are taught. The continents that are recognized by the majority of people are Europe, Asia, Africa, Australia, North America, South America, and Antarctica. Some people may group Europe and Asia as Eurasia, and may group further into Afro-Eurasia/the Old World.

Science shows that Earth formed around 4.5 billion years ago. The organisms that live on Earth have completely changed Earth's air (atmosphere); this is called a biosphere. 71% of Earth's surface is covered in saltwater oceans. Earth is the only place in the Solar System where liquid water is known to exist at present. The other 29% is made of rocky land in the shape of continents and islands. Earth interacts with other objects in the Solar System, particularly the Sun and the Moon. The Earth orbits the Sun roughly once every 365.25 days. One spin is called a day and one orbit around the Sun is called a year. This is why there are 365 days in a year, but a leap day added to the calendar once every 4 years.