The Earth

The Earth is one of eight planets in the solar system, and the third one of the Sun counting from inward to outward, about 150,000,000 km away from the Sun. The Moon is the only natural planet of the Earth and also the nearest celestial body from the Earth (the average distance from the Earth is 384,400km) The Earth rotates from west to east on its own axis and revolves around the Sun at the same time. Rotation and revolution of the Earth incurs the alternation of day and night and change of the seasons.

The Earth-basic parameters
Age: 4,600million years
Period of revolution: 365.256 days
Orbit of revolution: in an elliptical shape
Period of rotation: 23.9345 hours
Diameter of the Earth: 12,756km
Mass: about 600,000 hundred million tons
Superficial area of the Earth: 510 million km2
Principal constituents in the atmosphere: nitrogen (78.5%) and oxygen (21.5%)
Principal constitutents in the crust: oxygen (47%), silicon (28%) and aluminum (8%)
Satellite (natural): 1 (the Moon)
According to the distance from the Sun, successively from the far to the near, are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune.