Earth sphere

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An earth sphere describes a phenomenon of the planet earth that has a spatial extent and usually wraps around the whole celestial body like a more or less continuous shell.

term

An increased use of the word earth sphere in scientific literature can be established from the middle of the 19th century. At that time, however, the word was still used as a synonym for "globe" or "planet earth". At the beginning of the twentieth century, today's word meaning emerged. In the German-speaking area, it was significantly shaped in 1903 by the German geographer Alfred Hettner . Since then, earth sphere has formed . the generic term, under which atmosphere, geosphere, lithosphere and many other sphere terms are collected.

shape

The atmosphere is like a bowl around the earth. In this it resembles many other earth spheres.

Many of the most famous earth spheres have the shape of closed shells. Like hollow spheres, they lie around the entire planet like shells. Such continuous, shell-like earth spheres are, for example, the atmosphere and the lithosphere . The air of the atmosphere on the one hand envelops the entire solid earth, whose outer shell is on the other hand formed everywhere by the lithosphere.

Other spheres of the earth also have a shell-like appearance, but their shells have gaps. Such patchy, shell-like earth spheres are, for example, the cryosphere and the granitosphere . The large ice sheets of the cryosphere are located on the one hand in Greenland and the Antarctic, but between the two areas there is a huge, non-iced corridor with only a few switched-on mountain glaciers. On the one hand, the granitoid rocks of the granitosphere form large-volume parts of the continental crust, but they are completely absent within the oceanic crust.

A few earth spheres have nowhere extensive areas. Instead, they are found in many small deposits all over the world. So their appearance is less like a shell than a pattern of spots. If the various occurrences are related and exchanged with one another, a web-like appearance can also be assumed. Such patchy or net-like earth spheres are, for example, the pyrosphere and the noosphere : the magmas of the pyrosphere on the one hand do not form a continuous global layer, but are split up into many individual occurrences. The noosphere, on the other hand, arises from the network-like, communicative exchange between people who create ideas and people who develop ideas.

Due to its shape, the inner core of the earth is an exception among the earth spheres. Because the inner core of the earth does not form a hollow sphere, but a full sphere with the center of the earth as its center.

location

Gas bubbles in ice: The atmosphere penetrates the cryosphere.
The deep earth spheres remote from the surface were identified by seismological analysis of earthquake waves.

Many earth spheres are completely or largely on the earth's surface - or at least just above or below it. Such earth-surface spheres are, for example, the decomposition sphere with its weathering blankets and the phytogeosphere , which includes all terrestrial plants.

Some earth spheres envelop the planet at a smaller or greater distance from the earth's surface, without being directly connected to it. Such high earth spheres remote from the surface of the earth are, for example, the exosphere as the uppermost layer of the atmosphere and the electrosphere , within which the atmosphere has a higher electrical conductivity.

In addition, there are a number of earth spheres that lie completely some distance below the earth's surface. Such deep earth spheres remote from the surface of the earth are for example the asthenosphere as a layer of slightly melted rocks below the lithosphere and the barysphere , which is mainly made up of iron and is located in the center of the planet.

In addition, many of the earth's spheres do not coexist finely separated. Instead, they permeate and permeate each other in many ways. Such penetrating earth spheres are, for example, the hydrosphere and the atmosphere, both of which - as soil water and soil air - pervade the soils of the pedosphere .

Development over time

Based on the Endmoränenzüge the Saale-icing (yellow) and the Weichselian icing (red) in North Germany can be understood, the width of the cryosphere that changes erdzeitlich.
Diurnal change of the ionosphere.
The area of ​​the Chionosphere - the snow cover worldwide - fluctuates with the seasons.

The shape and position of earth spheres can change over time. Nor have they existed since the beginning of the earth. Instead, they formed at specific times and will very likely go away at some point. Examples:

  • The expansion of the ionosphere is subject to daily fluctuations. It is formed in the high atmosphere by ionizing rays from the sun. Because of the lack of solar radiation, it degrades almost completely at night.
  • The expansion of the Chionosphere - the snow-covered areas of the earth - is subject to seasonal fluctuations. During the winter, their snow cover can spread widely. On the other hand, it shrinks in summer except for a few snow fields in high mountains and polar regions.
  • The expansion of the cryosphere is subject to fluctuations in time. During the cold periods , the sea ice can penetrate far towards the equator and large areas of the continents are buried under the inland ice. During the warm periods , the cryosphere retreats very far into the highest mountain and polar regions. During the period of the Cryogenium , almost the entire earth was covered with ice several times .
  • The ozonosphere was only formed a little over two billion years ago. Previously, certain microorganisms had evolved oxygenic photosynthesis. Large quantities of oxygen molecules now escaped from the oceans and made their way into the atmosphere. The oxygen molecules rose and were converted by sunlight into the ozone molecules of the ozonosphere.
  • The magnetosphere is formed by the earth's magnetic field, which is generated by the heat flow within the liquid iron alloy in the outer core of the earth . The Earth's magnetic field will pass in three billion to four billion years, when the Earth's outer core is almost completely hardened.

groups

The earth spheres can be divided into three groups. The first group consists of the natural earth spheres . The natural earth spheres exist without human intervention. Their existence is therefore fundamentally independent of human culture - although many of them are nowadays influenced in many ways by human activity. The exploration of the natural spheres of the earth is the responsibility of physiogeography ( natural geography ) and the other natural scientific geosciences . The natural earth spheres include, for example, the hydrosphere and the ecosphere.

The second group of earth spheres consists of the culture-related earth spheres . The culturally conditioned spheres of the earth arise and exist only through human intervention. So their existence depends on human culture . Research into the culturally conditioned spheres of the earth is the responsibility of anthropogeography ( cultural geography ) and cultural studies . The culture-related earth spheres include, for example, the anthroposphere and the noosphere.

The third group of earth spheres consists of the partially natural earth spheres . In partially natural earth spheres, both natural and culture-related spatial properties in their diverse mutual interpenetration and interaction are viewed collectively and collectively. The exploration of the partially natural earth spheres is the responsibility of general geography . The landscape sphere is one of the partially natural earth spheres .

criticism

The idea of ​​earth spheres - the concept of separating out shell-like spaces with certain properties - was pioneered for modern science by the British doctor Hugh Doherty. It was adopted in 1871 and simplified by the American philosopher Stephen Pearl Andrews. Four years later the concept was found in a publication by the respected Austrian geologist Eduard Suess :

"Just as one has learned to divide the sun into a number of concentric shells, one can probably also divide the earth into shells, each of which, however, has multiple connections with the next one."

- Eduard Suess : The emergence of the Alps. P. 158.

With the work of Eduard Suess, the idea of ​​earth spheres can be considered established since 1875. With this, frames of thought were introduced into the geosciences, which now made it possible to identify separate geoscientific disciplines in a specialization process. Because from now on the earth no longer needs to be researched in its entirety. From now on it was sufficient to specialize in matters only of the lithosphere, atmosphere, hydrosphere and so on. In the process, the sense of the interrelationships of the earth could be lost in its entirety - the "multiple connections" between the earth spheres, which Suess had explicitly mentioned , got out of sight. It was the German geographer Friedrich Ratzel who tried to counteract this in 1902 and made an early plea for a holistic view of the earth:

“The first must be the consideration of the whole, and only a long way after that does the division come into parts, because the appraisal of the parts depends on the conception of the whole. [...] The shell of water and air is nowhere to be precisely separated from the solid earth. […] This conception of the earth, which regards the solid, liquid and air-like, as well as all life that blossoms from and in them, as a whole that belongs together through history and uninterrupted interaction, we contrast as an organic conception of the earth with those who make up these parts of the globe breaks apart like those who have come together by chance and thinks that they can understand one without the other. Perhaps the expression hologean earth conception would be more undoubted; but we are averse to the introduction of newly formed foreign words. "

- Friedrich Ratzel : The earth and life. Second volume, pp. 3–4.

With his hologean conception of the earth, Ratzel criticized the tendency to separate individual earth spheres from the overall network and to consider them for themselves. In the century after him this criticism was occasionally renewed. This happened more and more after 1948, when the American mathematician Norbert Wiener introduced cybernetics into the scientific discussion. According to the system concept of cybernetics, the earth can be understood as a comprehensive system of system elements interacting in a variety of ways. Their interactions can easily break through the relatively rigorously conceived enclosures of an earth sphere. In this way the boundaries between the earth's spheres are blurred. The concept of the earth sphere was criticized with particular prominence by the British chemist James Ephraim Lovelock :

"[The concept of Gaia] is concerned with the working of the whole system [of earth], not with the separated parts of a planet divided arbitrarily into the biosphere, the atmosphere, the lithosphere, and the hydrosphere. These are not real divisions Of the Earth, they are spheres of influence inhabited by academic scientists. "

“[The Gaia concept] deals with the work processes of the whole system [of the earth], not with separated pieces of the planet, arbitrarily divided into the biosphere, the atmosphere, the lithosphere and the hydrosphere. They are not real [independent] sections of the earth, instead they are spheres of influence that are inhabited by academic scientists. "

- James Ephraim Lovelock : Healing Gaia. P. 11.

Holistic approaches

The system earth includes all things in all earth spheres, together with their diverse - also interdependent - interactions.

Twenty years after Ratzel's appeal for a hologean conception of the earth, the Russian geoscientist Vladimir Ivanovich Vernadski was lecturing at the Sorbonne in Paris on an ecosystem that was supposed to span the entire earth. He called it the biosphere . It can also be used as an ecosphere since 1958 . are designated.

Furthermore, in the late 1950s and early 1960s, several terms were proposed to denote the space in which things exist and interact with each other that are explored by the science called geography . These concepts are also aimed at holistic considerations. It was about the (geographical) geosphere ( chorosphere ) and the landscape sphere .

Finally, from 1986 onwards, James Ephraim Lovelock developed the Gaia hypothesis as an alternative and holistic geoscientific approach. The contents of this hypothesis were integrated into the then newly named research field of System Earth from 1983 . The latter term is currently widely accepted. According to the concept of the system earth, the individual earth spheres are shown separately today, but their fundamental connection and their diverse mutual interactions are emphasized. They are considered as diverse subsystems ( subsystems ) of the larger, overarching and coherent system earth. This currently seems to have restored the view of the earth spheres that had already been formulated at the very beginning by Eduard Suess in 1875.

See also

literature

  • H. Eichler: Ecosystem Earth . Leipzig 1993, pp. 35-40.

Individual evidence

  1. ↑ H. Reinsch: Knowledge of nature . Speyer 1856, p. 27.
  2. ↑ C. Flammarion: The Majority of Inhabited Worlds . Dresden 1864, pp. 40-41.
  3. ↑ A. Hettner: Basic concepts and principles of physical geography. In: Geographical Journal. 9 (1903), pp. 23, 132.
  4. ^ HJ Schlichting: Phantom in the ice. In: Spectrum of Science. 01 (2010), p. 40.
  5. ^ PF Hoffman, AJ Kaufman, GP Halverson, DP Schrag: A Neoproterozoic snowball Earth. In: Science . 281 (1998), pp. 1342-1346.
  6. ^ C. Goldblatt, TM Lenton, AJ Watson: Bistability of atmospheric oxygen and the Great Oxidation. In: Nature . 443 (2006), p. 683.
  7. ^ AJ Meadows: The Future of the Universe . London 2007, p. 34.
  8. ^ DJ Stevenson: Introduction to planetary interiors. In: Proceedings of the International School of Physics "Enrico Fermi". 147 (2002), p. 605.
  9. ↑ H. Doherty: Organic Philosophy or Man's True Place in Nature Volume I - Epicosmology . London 1864.
  10. ^ SP Andrews: The Primary Synopsis of Universology and Alwato . New York 1871, p. 105.
  11. ↑ E. Suess: The emergence of the Alps . Vienna 1875.
  12. ↑ E. Suess: The emergence of the Alps . Vienna 1875, p. 158.
  13. ↑ F. Ratzel: The earth and life. Second volume, Leipzig / Vienna 1902.
  14. ↑ K. Herz: Large-scale and small-scale landscape analysis in the mirror of a model. In: Petermanns Geographische Mitteilungen. Supplementary Volume 271 (1968), pp. 49-50.
  15. ^ WC Peters (ed.): Proceedings: Of the Conference on Mining and Ecology in the Arid Environment, March 22 to 27, 1970, Ramada Inn, Tucson, Arizona. Tucson, 1970, p. Vi.
  16. ↑ H. Eichler: Ecosystem Earth . Leipzig 1993, pp. 40-41.
  17. ^ JE Lovelock: Healing Gaia . New York 1991.
  18. ↑ VI Vernadsky: La Géochimie . Paris 1924.
  19. ^ E. Neef: Geography and Environmental Science. In: Petermann's geographical communications. 116 (1972), p. 82.
  20. ↑ LC Cole: The ecosphere. In: Scientific American 4 (1958), pp. 83-92.
  21. ^ H. Carol: On the discussion of landscape and geography. In: Geographica Helvetica. 11 (1956), pp. 113-114.
  22. ^ E. Winkler: On two newer geographical "basic concepts". In: Geographica Helvetica. 15 (1960), p. 48.
  23. ↑ Ефремов, Георгий (Юрий) Константинович: Ландшафтная сфера Земли. In: Известия Всесоюзного географ об-ва. 6: 525-528 (1959).
  24. ^ E. Winkler: On two newer geographical "basic concepts". In: Geographica Helvetica. 15 (1960), p. 48.
  25. ^ JE Lovelock, CE Giffin: Planetary atmospheres: compositional and other changes associated with the presence of life. In: Advances in the Astronautical Sciences. 25: 179-193 (1969).
  26. ^ JE Lovelock: Gaia as seen through the atmosphere. In: Atmospheric Environment . 6: 579-580 (1972).
  27. ↑ JR Lovelock: Gaia: A New Look at Life on Earth . Oxford 1979.
  28. ^ Earth System Science Committee: Earth System Science: A Program For Global Change . Washington DC 1986.
  29. ↑ P. Amtsfeld, J. Bauer, A. Gehrke, A. Hebel, F. Kietz, FP. Mager, M. Schmidt, I. Werb, J. Wetzel: SEYDLITZ Geographie 5/6 · Baden-Württemberg . Braunschweig 2008, pp. 118–119.
  30. ↑ RFJ Hüttl: A planet full of surprises: New insights into System Earth / Our Surprising Planet: New Insights into System Earth . Heidelberg 2011.
  31. ^ HJ de Blij, PO Muller: Physical Geography of the Global Environment . New York 1993, p. 13.
  32. ↑ P. Amtsfeld, J. Bauer, A. Gehrke, A. Hebel, F. Kietz, FP. Mager, M. Schmidt, I. Werb, J. Wetzel: SEYDLITZ Geographie 5/6 · Baden-Württemberg . Braunschweig 2008, p. 118.
  33. ↑ E. Suess: The emergence of the Alps . Vienna 1875, p. 158.