User:EveDK/TWA/Earth





=Earth=

Earth, also known as the Blue Planet, Planet Earth, and Terra, is the only planet currently known to host life. It is home to millions of species of plants and animals, including humans. The organisms that live on Earth have radically changed the composition of its atmosphere.

Earth is the only place in the Solar System where liquid water is currently known to exist, with 71% of its surface covered in salt water oceans. The other 29% is made of rocky land in the shape of continents and islands. Although different regions of the planet contain many dissimilar climates, from the arid Sahara Desert to the tropical Amazon Forest to the frozen continent of Antarctica, Earth is currently believed to be the planet best suited for human habitation.

According to current research, the Earth formed approximately 4.5 billion years ago. Earth is the third planet from the Sun. It is one of the four terrestrial planets in our Solar System: most of its mass is solid. (The other three terrestrial planets are Mercury, Venus, and Mars.)

Earth has notable gravitational relationships with the Sun and the Moon. The Earth orbits the Sun approximately once every 365.25 days (a day being a single rotation of the Earth about its axis), which makes one year (with a leap day added once every 4 years). The Moon orbits the Earth approximately every 27.3 days, which is the basis of the 28-day lunar month.