Earth

Earth is the third planet from the Sun and by its ideal distance of 149.8 million km (93.5 million miles) to the star, it is the only world in the near the star with life. Unlike any other planet in the Solar System, Earth has lots of water and posesses it in three forms (ice, liquid and vapour). It is also the largest terrestial planet and the fifth largest planet in the system. (''see List of largest planets in the Solar System). ''The Earth has one natural satelite, the Moon. The moon is about a quarter the size of the planet and is probably another body which was captured by the planet's gravity. A new theory says that the formation of the Moon started when a massive rocky body crashed into Earth about 4.52 billion years ago. The body was destroyed in impact and fragments from the Earth were flung out into orbit around it. Pieces from the destroyed body and Earth made a ring around the planet and shortly the pieces joined together by dust and rock to form the Moon. The Moon is the only body (now) explored by astronauts. It is 3 days (252,000 miles, 384,000 km) away from the Earth, but astronauts only take four hours to reach it. The satellite is the largest satelite of a terrestrial planet.

Geography
Earth is divided into 7 continents, (from largest first): Earth has seven highest peaks, with Mount Everest being the highest and the third highest in the Solar System.
 * Asia (Size: 43,820,000 km², percent of landmass: 29.5%, total population: 4,164,252,000)
 * Africa (Size: 30,370,000 km², percent of landmass: 20.4%, total population: 1,022,234,000)
 * North America (Size: 24,490,000 km², percent of landmass: 16.5%, total population: 542,056,000)
 * South America (Size: 17,840,000 km², percent of landmass: 12%, total population: 392,555,000)
 * Antarctica (Size: 13,720,000 km², percent of landmass: 9.2%, total population: 1,000)
 * Europe (Size: 10,180,000 km², percent of landmass: 6.8%, total population: 738,199,000)
 * Australia (Size: 9,008,500 km², percent of landmass: 5.9%, total population: 29,127,000)
 * Mount Everest (Continent: Asia, height: 29,029 feet (8,848 meters)
 * Aconcagua (Continent: South America, height: 22,830 feet (6,960 meters)
 * Mount McKinley (Continent: North America, height: 20,335 feet (6,198 meters)
 * Kilmanjaro (Continent: Africa, height: 19,341 feet (5,895 meters)
 * Mount Elbrus (Continent: Europe, height: 18,481 feet (5,633 meters)
 * Vinson Massif (Continent: Antarctica, height: 16,050 feet (4,892 meters)
 * Puncak Jaya (Continent: Australia, height: 16,024 feet (4,884 meters)

Structure
Earth is a large planet, composed of a thin, sillicate crust about 60 km (35 miles) deep, a hot, semi-molten mantle and a small core of iron which is molten on the outside, but solid inside. The core is hot, with a temperature of about 8,000°C and powers the gravity, atmosphere, and magnetic field.

Atmosphere
Earth's atmosphere is a thick layer of nitrogen, mixed with oxygen and water vapor. A special form of oxygen protects the surface from harmful solar radiation, permitting life on land. The nitrogen gives out the blue color of the sky. The clouds are composed of water vapor. Trees extract CO² and use photosynthesis to turn it into oxygen. Oxygen is also the air that humans need to survive.