EARTH

 

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.

Earth is estimated to consist of the earth's core consists of iron-nickel-thick frozen 1370 kilometers with a temperature of 4500 ° C, covered well by the liquid outer core that is 2100 kilometers thick, and covered also by 2800 kilometers thick silica coat formed 83% of the earth and finally once covered by a thick crust of approximately 85 kilometers.

The crust is thinner on the sea floor that is about 5 kilometers. The 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 the Earth's surface is as high as Mount Everest is 8,848 meters and the deepest point is the Mariana Trench in the Pacific ocean with a depth of 10,924 meters. Lake Baikal is the deepest lake with a depth of 1637 meters, while the largest lake is the Caspian Sea with an area of ​​394,299 km2.

Composition and structure

Earth is a terrestrial planet, meaning made of rocks, different than gas giants like Jupiter. This planet is the largest of the four terrestrial planets, in the second sense, the mass and size. Of the four terrestrial planets, Earth also has the highest density, the largest surface gravity, magnetic field the strongest and most rapid rotation. Earth is also the only terrestrial planet that has an active plate tectonics.

Form

Rotation round the earth in a north-south axis that results in day and night

The shape of planet Earth is very similar to the oblate spherical (oblate spheroid), a sphere is pressed flat on the orientation of the poles that cause buncitan at the equator. Buncitan This occurs because the Earth's rotation, causing the equatorial diameter 43 miles greater than the diameter from pole to pole. Average diameter of the sphere of the earth is 12,742 km, or roughly 40,000 km / π. Because the meter was originally defined as the distance between the equator 1/10.000.000 to the north pole through Paris, France.

Local topography varies slightly from the ideal form of a smooth sphere, although on a global scale, this variation is very small. Earth has a tolerance of about one in 584, or 0.17% compared to a perfect sphere (reference spheroid), which is more smooth when compared with the tolerance of a billiard ball, 0.22%. Largest local deviations in the Earth's surface is Mount Everest (8848 m above sea level) and the Mariana Trench (10,911 m below sea level). Because buncitan equator, the earth which is located farthest from the midpoint of the Earth is actually Mount Chimborazo in Ecuador.

Endogenous natural processes / personnel are endogenous earth energy that comes from within the earth. Workers are building the endogenous nature of this earth's surface. Exogenous natural power coming from extraterrestrial and destructive. So the power that makes a wide range of relief on the face of this earth as we know that the earth's surface which we live is made up of various formations such as mountains, valleys, hills, lakes, rivers, etc.. The existence of such formations, causing the earth's surface becomes uneven. Formations are known as relief of the earth.

The chemical composition

Oxide crust table F. W. Clarke Compound Formula Composition

Silica SiO2 59.71%

Alumina Al2O3 15.41%

lime CaO 4.90%

Magnesia MgO 4.36%

Sodium oxide Na2O 3.55%

Iron (II) oxide FeO 3.52%

Potassium oxide K2O 2.80%

Iron (III) oxide Fe2O3 2.63%

Water H2O 1.52%

Titanium dioxide TiO2 0.60%

Pentaoksida Phosphorus P2O5 0.22%

Total 99.22%

Earth's mass is approximately 5.98 × 1024 kg. Main content of iron (32.1%), oxygen (30.1%), silicon (15.1%), magnesium (13.9%), sulfur (2.9%), nickel (1.8%) , calcium (1.5%), and aluminum (1.4%), and 1.2%, the rest consisting of various rare elements. Because the mass separation process, the earth's core is believed to have a major content of iron (88.8%) and small amount of nickel (5.8%), sulfur (4.5%) and the rest is less than 1% of rare elements.

Geochemist F. W. Clarke calculated that approximately 47% of the earth's crust consists of oxygen. The most common rocks found in the earth's crust are nearly all oxides (oxides), chlorine, sulfur and fluorine are the exception and the amount in the rocks are usually less than 1%. The main oxides are silica, alumina, iron oxide, lime, magnesia, potash and soda. The main function is as acidic silica, which form the silicate. It is the nature of the various minerals of igneous rocks are most common. Based on the calculation of 1.672 analysis of various types of rocks, Clarke concluded that 99.22% of rock composed of 11 oxides (see table right). Other constituents occur only in small quantities.

Layers of earth

According to the composition (type of material), the Earth can be divided into layers as follows:

* The crust of the Earth

* Earth's mantle

* The core of Earth

Meanwhile, according to the mechanical properties (properties of the material) it, the earth can be divided into layers as follows:

* Litosfir

* Astenosfir

* Mesosfir

* Earth's outer core

Earth's outer core is one that lines the inside of the Earth's inner core of the earth. Earth's outer core has a thickness 2250 km and a depth of between 2900-4980 km. Earth's outer core consists of molten iron and nickel with a temperature of 3900 ° C.

* Earth's inner core

Earth's inner core is the deepest part of the earth or the earth's core can also be called. Earth's core has a diameter of 2600km and 1200km thick. Earth's core consists of solid iron and nickel with the temperature can reach 4800 ° C.