earth

Earth is the third planet from the eight planets in the Solar System. Estimated to reach 4.6 billion year age. The distance between the Earth to the Sun is 149.6 million kilometers or 1 AU (English: Astronomical Unit). At the Earth's rotation is 23 hours 56 minutes 4 seconds. While at the time of revolution is 365.25 days. Earth has a layer of air (atmosphere) and the so-called magnetic field (magnetosphere) that protect Earth's surface from the solar wind, ultraviolet light and radiation from space. This air layer surrounds the Earth to a height of about 700 kilometers. The air layer is divided into Troposphere, stratosphere, mesosphere, thermosphere and exosphere.

The ozone layer, as high as 50 kilometers, are in the stratosphere and mesosphere and protects the Earth from ultraviolet rays. The difference in the surface temperature of the Earth 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 weighing 59 760 billion tons, with a surface area of ​​510 million square kilometers. The density of the Earth (about 5,500 kilograms per cubic meter) is used as a unit of weight ratio of any other type of planet, the gravity of the Earth is set as 1.

The Earth has a diameter of 12,756 kilometers long. Earth's gravity is measured as 10 N kg-1 be a unit of measure of the gravity of other planets, the Earth's gravity is set as 1. Earth has one natural satellite is the moon. 70.8% of Earth's surface covered with water. Earth Air consists of 78% nitrogen, 21% oxygen and 1% water vapor, carbon dioxide and other gases.

Earth estimated to be made up in the Earth's core consists of iron-nickel-thick frozen 1370 kilometers with temperatures 4500 ° C, is also covered by a liquid outer core that is 2100 kilometers thick, and covered also by the 2800 kilometer-thick mantle of silica forming 83% content of the Earth and eventually completely covered by the Earth's crust about 85 kilometers thick.

Thinner crust on the ocean floor is about 5 kilometers. Earth's crust is divided to several parts and moving through the movement of tectonic plates (the theory of continental drift) that produce earthquakes.

The highest point on Earth's surface as high as Mount Everest is 8,848 meters and the deepest point is the Mariana trench in the Pacific with a depth of 10,924 meters. Lake Baikal is the deepest lake with a depth of 1637 meters, the largest lake is the Caspian Sea with an area of ​​394,299 km2.