User:Mike Slice/TWA/Earth





=Earth= The Earth is the third planet from the Sun. It is one of the four terrestrial planets in the 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 home to millions of species of plants and animals, including humans.

Scientists estimate that the Earth formed around 4.5 billion years ago. The organisms that live on Earth have completely changed its air (atmosphere); this is called a biosphere. Earth is the only place in the Solar System where liquid water is known to exist at present. 71 per cent of Earth's surface is covered in salt water oceans. The other 29% is made of land in the form of continents and islands.

Earth interacts with other objects in the Solar System, particularly the Sun and the Moon. The Earth orbits or goes around 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 is added once every 4 years