Surface of the earth
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The surface of the earth is the interface between the solid earth's crust (including the soil ) and the bodies of water on the one hand and the atmosphere on the other. It can be divided into hemispheres (hemispheres, from ancient Greek ἥμισυς hemisys "half" and σφαῖρα sphaira "sphere") according to various criteria , i.e. in halves of the earth's surface.
Terrain heights on the Earth's surface to the mean sea level relative. This level surface - the geoid - has approximately the shape of an ellipsoid and a surface of 510 million km², of which around 71% is covered by oceans.
Ways of looking at geosciences
- The Physical Geography deals with the majority of the earth's surface and its system contexts.
- The geomorphology (part of geography) explores the exact shape (relief) of the earth's surface and (together with the Geology ) its origin. 37.4% of the earth's land surface is between 1000 and 2000 m above sea level .
- The Geodesy is concerned with the measurement of the earth's surface and infrastructure located on it, and - together with the geophysics - with the Earth's gravity .
- The Soil Science examines the uppermost organic embossed layer below the earth's surface.
In large parts of the land areas, especially in plains and hilly landscapes in regions with a humid climate , soil formsthe top layer below the earth's surface. It arises from the weathering of solid rock and from loose rock through the enrichment of these mineral substances with organic matter ( humus ). Depending on the degree of weathering, the chemical and physical properties of the parent rock and the prevailing environmental conditions, different soil types and types are created . In mountainous areas, especially in the high mountains and under extreme climatic conditions, however, the earth's surface often consists of bare rock or loose rock that is hardly or notsubjected toany soil formation processes .
Breakdown by hemispheres
- Geodesy: the North - and the southern hemisphere , as they result from the width with respect to the Earth's equator , and that referred eastern and western hemisphere , according to the longitude with respect to the zero meridian and the 180th meridian. The only state on earth whose territory lies in all four earth hemispheres is Kiribati , an island state in the Pacific .
- Geomorphology: The water hemisphere and the land hemisphere . The former covers the entire Pacific area and is 89% covered by seas, the latter roughly the Atlantic area and Eurasia with about 50% mainland.
- In addition, the northern and southern hemisphere as well as the western and eastern hemisphere designate cultural and economic-political divisions, which are chosen relatively arbitrarily. Its use in this context established itself during the Cold War period in the middle of the 20th century. The southern hemisphere referred to the Third World , the eastern hemisphere to the area of Europe and Asia ( Second World ) influenced by communism or real socialism . Today, due to the changed geopolitical situation, this classification is hardly used in specialist literature.
- In the treaties of Tordesillas and Saragossa (1494, 1529), in the course of colonialism, the surface of the earth was divided according to longitude into a Spanish and a Portuguese sphere of influence.
- The division into Old World (Eurasia, Africa) and New World (both America) is still common, which is also relatively unspecific.
Breakdown by water and land
Geomorphology divides the earth's surface into areas that are covered by water : lakes , rivers and seas , and areas that are not covered by water: mainland and islands .
While the term "surface" for areas not covered by water is relatively simple to understand as the interface between the lithosphere and / or pedosphere and the atmosphere ( top edge of the terrain ), for water bodies it refers either to the visible water surface ( water level ) or the interface between the lithosphere (including the sediments or " subhydrischen floors ") and water body ( a body of water , engl. sediment-water interface ). On closer examination, however, alternatively, the "visible from the top" surface, including the is also in the land masses vegetation cover and superstructure ( topography ) , or only ground surface ( orography ) meant.
In large-area glaciated regions such as the Arctic and the Antarctic , where parts of the ice sheet extend far into the coastal waters as ice shelves , the question arises whether the surface of the ice body is part of the earth's surface or not.
Data
| Total area of the earth |
510,000,000 km² | 100% |
| Water surface | 360,570,000 km² | 70.7% |
| Land area | 149,430,000 km² | 29.3% |
Land area
The share of the land area is about 148.9 million km² (29%); the country is spread over continents and islands:
| continent | Land area | proportion of |
|---|---|---|
| Asia (excluding the polar islands) | 44.4 million km² | 31% |
| America (excluding polar regions) | 38.3 million km² | 27% |
| Africa | 29.3 million km² | 20% |
| Antarctica | 13.2 million km² | 9% |
| Europe (excluding Iceland , Novaya Zemlya , Atlantic Islands) | 9.9 million km² | 7% |
| Australia (with Tasmania ) | 7.7 million km² | 5% |
| total | 148.9 million km² | 100% |
In relation to the ice-free areas of the world (i.e. excluding the majority of Greenland and Antarctica), the land area is characterized by natural and man-made large habitats , which at the beginning of the 21st century comprise the following orders of magnitude:
|
Permanent human space (residential areas, infrastructure, intensively used areas) 2004 |
72,084,920 km 2 | 53% |
| Agricultural area in 2009 | 48,827,330 km 2 | 35.9% |
| Extensively or seasonally used natural space 2004 | 42,162,880 km 2 | 31% |
| total forest area (used and unused) 2010 | 40,204,320 km² | 29.6% |
| Unused, “wild” natural spaces 2004 | 21,761,480 km 2 | 16% |
Water surface
The share of the water surface is approx. 361.2 million km² (71%); the water is mainly distributed in oceans :
| ocean | % | middle deep |
|---|---|---|
| Pacific Ocean | 47% | 3870 m |
| Atlantic Ocean | 24% | 3380 m |
| Indian Ocean | 20% | 3600 m |
| Southern ocean | 5% | |
| Arctic Ocean | 4% |
Heights (hypsometry)
The mean height of the mainland areas is around 700 m (Europe 300 m, Asia 880 m, America 610 m, Africa 660 m, Oceania and Australia 300 m). The earth's surface reaches its highest point with Mount Everest at 8,848 meters above sea level. The deepest freely accessible point on the earth's surface is on the shores of the Dead Sea , the water surface of which is 423 meters below sea level. The deepest point of the surface of the continental crust is under the Denman Glacier of the Antarctic Ice Sheet , where it reaches a depth of about 3,500 m below sea level. The mean depth of the seas is about 3,500 m and the deepest point of the surface of the earth's crust or the lithosphere is in the Mariana Trench at about 11,000 meters below sea level.
Other heavenly bodies
Comparison of the surface of the earth with other planets of the solar system and the earth's moon:
| Heavenly bodies | Surface in km² |
|---|---|
| Jupiter * | 61,420,000,000 |
| Saturn * | 42,610,000,000 |
| Uranus * | 8,083,000,000 |
| Neptune * | 7,620,000,000 |
| earth | 510,100,000 |
| Venus | 460,200,000 |
| Mars | 144,600,000 |
| Mercury | 74,760,000 |
| moon | 37,960,000 |
(*) Please note that Jupiter, Saturn, Uranus and Neptune are gas planets without a solid surface. With them, the "surface" is calculated using the zero level , which is by definition the level at which the gas pressure is 1 bar .
Web links
Individual evidence
- ↑ Conradin Burga, Frank Klötzli and Georg Grabherr (eds.): Mountains of the earth - landscape, climate, flora. Ulmer, Stuttgart 2004, ISBN 3-8001-4165-5 , p. 21.
- ↑ All details are rough numbers. Source: ( Page no longer available , search in web archives )
- ↑ All information roughly; Sources see table
- ↑ a b c Study Last of the wild, version 2. At: SEDAC.ciesin.columbia.edu. “Socioeconomic Data and Applications Center” of the “Center for International Earth Science Information Network (CIESIN)” at Columbia University, New York. Accessed in September 2012. Percentages of the study applied to ice-free land area in km 2 .
- ↑ to World Bank - World Bank Data ; converted to ice-free land
- ↑ to World Bank - World Bank Data ; converted to ice-free land
- ↑ Mathieu Morlighem, Eric Rignot, Tobias binder and 34 other authors: Deep glacial troughs and ridges stabilizing unveiled beneath the margins of the Antarctic ice sheet . In: Nature Geoscience . December 12, 2019, doi : 10.1038 / s41561-019-0510-8 (English).