User:Aredbee/TWA/Earth





=Earth= 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. Earth is also called the Blue Planet, Planet Earth, Terra, and the globe.

Earth is home to millions of species of plants and animals, including humans.

Earth is the only planet in the galaxy that is known to support life. It has many places that are suitable for humans to live; although, some areas of the planet can be dangerous or uninhabitable for humans. Plant and animal life, however, can be found everywhere on the earth.

Science shows that 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. 71% of Earth's surface is covered in saltwater oceans. At present, Earth is the only place in the Solar System where liquid water is known to exist. The other 29% of the surface consists of rocky land in the form of continents and islands. Earth interacts with other objects in the Solar System, particularly the Sun and the Moon. Earth completes a full orbit around the Sun–—called a year——roughly once every 365.25 days. This is why we measure a year as 365 days on the calendar, but must add a leap day every 4 years. Earth spins on its axis as it orbits the Sun; a full spin, or rotation, takes 24 hours, which is called a day. From a given reference point on the surface of Earth, a day begins as that point turns to face the Sun (sunrise) and ends as that point turns away from the Sun (sunset).