Earth is the third planet from the eight planets in the Solar System. Estimated to reach 4.6 billion years old. The distance between the Earth to the sun is 149.6 million kilometers or 1 AU (UK: astronomical units). Earth has a layer of air (atmosphere) and the so-called magnetic field (magnetosphere) which protect the Earth's surface from the solar wind, ultraviolet light and radiation from outer space. This layer of air surrounds the earth to a height of around 700 kilometers. The air layer is divided into Troposphere, stratosphere, mesosphere, thermosphere and Exosphere.
Ozone layer, as high as 50 kilometers, are in the stratosphere and mesosphere and protect the earth from ultraviolet rays. Earth's surface temperature difference is between -70 ° C to 55 ° C depending on the local climate. The day is divided into 24 hours and a year on earth equal to 365.2425 days. Earth has a mass weight of 59 760 billion tonnes, with a surface area of 510 million square kilometers. The density of the Earth (about 5,500 kilograms per cubic meter) is used as the unit of weight ratio of other types of planets, with Earth's gravity is set as 1.
Earth has a diameter of 12,756 kilometers long. Earth's gravity was measured as 10 N kg-1 used as a unit the size of the gravity of other planets, with Earth's gravity is set as 1. Earth has one natural satellite of the Moon. 70.8% of the surface of the earth covered with water. Earth Air consists of 78% nitrogen, 21% oxygen and 1% water vapor, carbon dioxide and other gases.
