Types of Earth Surface Theories – The earth that we live in today has been formed millions or even billions of years ago. One theory regarding the formation of the earth states that the sun existed first with the nebula that surrounds it. The nebula, which consists of clouds, dust and cosmic gas, rotates and eventually unites under the influence of gravity which then forms planets, one of which is Earth. See a more complete explanation of the Earth’s Surface Theory, Sinaumed’s.
The earth we live in has had a long process of development to the state we see today. Various theories put forward by experts to describe the process of development of the shape of the earth’s surface. This time we will discuss what theories describe the development of the shape of the earth’s surface.
To be able to understand more about everything about the universe, the solar system, and the celestial world, Sinaumed’s can read the book Getting to Know the Universe, the Solar System, and the Celestial Bodies below.
The theory of the formation of the earth has gone through a long and long way to reach the point where it is now known as the theory of Plate Tectonics. If we look far back, we can see traces of quite interesting theoretical developments.
At the time of Ancient Greece, people believed that the earth was the center of the universe in the form of a plate that ended in the form of a waterfall, based on hell and overshadowed by heaven. There is even a myth that the world is above the tortoise shell.
Ferdinand Magellan’s success circumnavigating the earth from Spain to South America-Pacific back to Spain via the Cape of Good Hope in South Africa in 1519-1521 proved that the earth was indeed round, breaking various earth theories that had developed at that time.
Kinds of Earth Surface Theory
1. Contraction Theory
The theory put forward by Descartes (1596-1650), who said that the earth will shrink and shrink over time from cooling so that the surface has various reliefs such as mountains, plains and valleys.
This theory received support from James Dana (1847- Elie de Baumant (1852), both of whom argued that the earth experienced shrinkage due to a cooling process occurring in the interior of the earth which resulted in the surface of the earth contracting and forming mountains and valleys.
2. The Two Continents Theory (Laurasia-Gondwana Theory)
Initially the earth consisted of two continents namely Laurasia which is around the north pole and Gondwana around the south pole of the earth. The two continents moved slowly towards the earth’s equator which eventually split to form small continents.
Laurasia split into North America, Asia, Europe. Meanwhile, Gondwana was divided into South America, Australia and Africa. The Laurasia-Gondwana theory was first discovered in 1884 by Edward Zeuss.
3. Continental Drift Theory
Continental Drift Theory The theory of continental drift was put forward by Alfred Lothar Wegener in 1912 in his book The Origin of the Continents and Oceans. Wegener put forward a theory about the development of the shape of the earth’s surface related to continental drift. According to Wegener, at the beginning of the earth’s surface there was only a large continent called Pangea (in Greek it means the whole earth), and an ocean called Panthalasa.
The continent then shifted slowly towards the equator and west to reach its present position. The theory of continental drift is reinforced by the similarity of the coastlines between South America and Africa, as well as the similarity of rock layers and fossils in layers in the two regions.
The movement, according to Wegener, is caused by the earth’s rotation which produces a centrifugal force so that the movement tends towards the equator, while the force of attraction between the earth and the moon produces a westward motion. This westward movement occurs as it does during a tidal wave, which is due to the revolution of the moon moving from west to east.
However, around the 1960s there was criticism of the theory which questioned the possibility of very large and heavy continental masses could slide on the hard ocean.
4. Convection Theory
This convection theory was first coined by Arthur Holmes around 1927 and then developed by Harry H. Hess and Robert Diesz. This theory states that there are convection currents from within the earth’s mantle which consist of masses in the form of lava.
When these convection currents bring lava to the surface of the earth in the mid-oceanic ridge, it will cause the lava to freeze and form a new layer of earth’s crust so that it shifts and replaces the old earth’s crust.
This theory is supported by evidence that there are parts of the mid-oceanic ridge itself, such as the mid-Atlantic Ridge and the Pacific Atlantic Ridge. Besides that, based on a study on the age of the sea, it is also proven that the farther from the mid-ocean ridge, the older the rocks are.
5. Tectonic Plate Theory
The theory put forward by Tozo Wilson around 1965 states that the earth’s crust consists of several tectonic plates that are above the asthenosphere layer, and the plates that make up the earth’s crust are always moving due to the influence of convection currents from the asthenosphere layer.
The movement of these tectonic plates can be divided into three types based on their direction, namely Convergence in the form of mutually colliding movements between tectonic plates, both continental and oceanic plates. Several mountains such as the young Himalayas, Alps, Rockies and Andes are said to be reliefs formed as a result of this convergence process.
Divergences, namely the movement away from each other between tectonic plates and Horizontal Faults, namely movements in opposite directions that cause friction between tectonic plates. The San Andreas Fault which stretches for 1,200 km is one of the reliefs formed as a result of this transform process. The following is a more detailed explanation:
- The movement of the plates approaching each other (Convergent) will cause collisions where one of the plates will sink under the other. The subduction area forms a deep trough, which is usually the path of strong earthquakes. Behind the subduction path, a series of magmatic and volcanic activities will form as well as various depositional basins. One example occurs in Indonesia, the meeting between the Indo-Australian plate and the Eurasian plate produces a subduction line in the south of Java and the Sumatran Volcano line.
- The movement of the plates away from each other (divergent) will cause thinning and stretching of the Earth’s crust and eventually new material will be released from the mantle to form magmatic or volcanic paths. An example of the formation of volcanoes in the Mid-Ocean Rims in the Pacific Ocean and the African Continent.
- The movement of each other (Transform) is characterized by the presence of large horizontal faults such as the great San Andreas fault in America
6. The Big Bang Theory
The Big Bang theory is the most popular theory and recently discovered by scientists. In this theory it is argued that the solar system did not occur by itself, but through a process over billions of years.
This theory itself states that in this universe there is a giant cloud of fog rotating on its axis. You can find a discussion of this and other solar systems in the Exploration of the Solar System book.
This spin is so fast that it causes some to go off center. In this theory it is also stated that there is a large part that forms a giant disc. This giant disk exploded to form a nebula.
This nebula (smoke) cooled over 4.6 billion years. From this process eventually formed the Milky Way. However, small parts of the giant fog cooled and condensed until they finally became planets, one of which is the earth we live in now.
7. Gas Tidal Tori (Tidal)
The theory put forward by James Jeans and Harold Jeffrey in 1918, a large star that approaches the sun at a short distance, which in turn causes tides on the body of the sun, when the sun is in a gaseous state. The cause of the tides is the mass of the moon and the distance between the moon and the earth is 60 times the radius of the orbit on earth.
However, if a star whose mass is approaching its magnitude with the sun approaches, then it will form a kind of mountain wave on the sun’s body, which occurs due to the star’s attraction. The mountains will become incredibly high and then form a kind of very large flare, which is extended by the mass of the sun and pointed towards the big star. Gradually these columns will break apart and then they will become separate objects.
In this hot tongue there is a density of gases and eventually these columns will break, then separate into separate objects, namely planets. The big star that causes the pulling on the parts of the sun’s body, continues its journey in the universe, so that gradually it will lose its influence on the planet in the shape of earlier.
The planets will revolve around the sun but when they surround the large planets the cooling process will be slow while on the small planets it will run faster.
8. Planetsimal Theory
This theory was put forward by Forest Ray Morton, an American astronomer and Thomas C. Chamberlein, a geologist in 1916. In their theory they argued that the sun had existed from the beginning. Once upon a time, there was a star that was bigger than the size of the sun approaching the sun.
This results in a tidal pull on the sun so that some of the sun’s material is detached and scattered in its orbit. Over time, the material resembles a giant flame and moves away from the sun. However, the smaller materials are swept up by the larger materials and then unite and rotate in their orbits. In the end, planets were created from this material, one of which is the earth we live on.
9. The Nebula Theory
Fog Theory Or What is Often Called (Nebula) From the era before Christ, experts have been thinking about how the earth formed. And one of them is the theory of fog or what is called a nebula which was introduced by Immanuel Kant in 1755 and Piere de Laplace in 1796.
Where they are both famous for Kant Laplace’s fog theory. This theory says that in the universe there are gases that gather to form fog or nebulae. Where is the attractive force between the gases which then forms a very large collection of fog and rotates faster and faster. In this very fast rotation process, the fog material on the equator is thrown and separated and solidifies due to cooling.
The part that is thrown becomes the planets in the solar system. The nebula theory is divided into several stages. The sun and the planets are still in the form of gas, where the fog is still very thick and large. The fog is still rotating and twisting strongly and compaction occurs at the center of the circle and then forms the sun.
You can find a deeper discussion about the solar system and the earth in Danang’s book below with the title Earth and the Solar System.
Then at the same time other matter formed into a smaller mass than the sun and then became planets, and moved around the sun. Then the material got bigger and always made regular movements around the sun in a fixed orbit then formed the levels of the sun family.
At this time on the surface of the earth there are six main plates.
- The Eurasian Plate, its territory includes Europe, Asia, and its suburbs include Indonesia.
- The American Plate, its area includes North America, South America, and the western half of the Atlantic Ocean.
- The African Plate, its territory includes Africa, the eastern half of the Atlantic Ocean, and the western part of the Indian Ocean.
- Pacific Plate, its area includes all plates in the Pacific Ocean.
- The India-Australia Plate, its territory includes the Indian Ocean plate and the Indian subcontinent in western Australia.
- The Antarctic Plate, its territory includes the Antarctic continent and the Antarctic Ocean plate. The movement of tectonic plates can cause different formations on the earth’s surface. The diversity of these forms is influenced by the direction and strength of plate motion. There are 3 possible strengths for the movement of the 2 plates, namely equally strong, equally weak, and one is strong, while the other is weak. The boundaries of tectonic plates are marked by the existence of natural formations due to the activity of the plates themselves. Tectonic plate boundaries can be divided into three types, namely convergent boundaries, divergent boundaries, and horizontal fault boundaries.
The Period of the Formation of the Earth
According to the geological calendar, the development of the earth can be divided into four eras, namely Archeozoic, Paleozoic, Mesozoic, and Neozoic (Cenozoic). During the Archean Period, which took place around 2.5 billion years ago, the earth at that time was still like a hot ball so there was no life.
The next period is the Paleozoic Period which lasted around 500–245 million years ago. The earth’s temperature is still unstable, but the rainfall is quite high and there are single-celled creatures. The Paleozoic is divided into five periods, namely the Cambrian (animals, namely jellyfish and fish), Silurian (living things, namely mosses, vascular plants, and small terrestrial arthropods), Devonian (animals, namely several types of sharks and amphibians), Carbon (the emergence of reptiles), and the Permian (the development of amphibians and other animals on land and water).
During the Mesozoic Era It took place around 245–65 million years ago. The earth’s temperature has stabilized and giant animals (dinosaurs) have appeared. This period is divided into three periods, namely the Triassic (dominated by reptile species), Jurassic (one of the animals, namely the reptile species), and Cretaceous (appeared primates and flowering plants, the period of the mass extinction of dinosaurs).
This period ended when a meteor hit the earth causing nearly 75% of life on earth to become extinct, as well as ending the age of the dinosaurs.
During the Neozoic or Cenozoic era, which took place about 60 million years ago, the natural state of the earth became more stable. The Neozoic Era is divided into two, namely the Tertiary Age and the Quaternary Age. In the Tertiary Age, various types of mammals emerged, namely apes and monkeys. The Quaternary Period, lasted 600,000 years ago. Beginning to appear signs of ancient human life. The Quaternary Age is divided into two periods, namely the Pleistocene (Diluvium) and the Holocene (Alluvium).
That’s all the information about the Theory of the Development of the Shape of the Earth’s Surface, hopefully this is useful, Sinaumed’s.
Source: from various sources