User:U2mik/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 home to millions of species of plants and animals, including humans.

Earth is the only planet in the galaxy known to support life. Earth has many places suitable for humans to live; however, some areas of the planet can be dangerous for humans or uninhabitable.

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. Seventy-one percent of Earth's surface is covered in saltwater oceans. Earth is the only place in the solar system where liquid water is known to presently exist. 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 four years to accommodate the extra .25 of the orbit made each year.