The Formation of Our Earth
The history of Earth touches on the configuration of the planet Earth from its inception several billions years ago to the present day. The formation of the Earth, which is a component of the solar system, involved forces, which can only be expressed as chaotic, blistering and divined. Earth was formed at approximately 4.54 billion years ago through buildup of the solar nebula. Scientists have revealed that our Solar System at the beginning contained nothing but only a cloud of dust particles that were spinning through empty space. Thus, the Earth’s formation involved a mammoth amount of environmental transformation in a time span, along with a biological change.
The Beginning of Solar System
Solar system began through the process of solar nebula hypothesis. The Solar system emerged after a large spinning cloud, which constituted interstellar dust and gases or solar nebula began to crumple (“Understanding Geological Time” 1). The collapse of the nebula is believed to have been activated by a shockwave coming from the explosion of stars. The explosion created waves in space, which pressed the cloud to remove gas and dust. The pressure in space caused the cloud to collapse while the gravity merged the gas and dust. As the cloud collapsed, it began to spin, leading to rise in temperature and density at the center.
The gas and the dust particles remained hot at the core but kept on cooling at the edges. Collision of dust particles led to accumulation of small asteroids and proto-planets and Earth was one of the proto-planets. As the cloud fell in large quantity, the center continued to heat, leading to the formation of the Sun, which consequently propelled most of the gas as well as the dust in the new solar system. The accumulation in the innermost part within the solar system generated other planets and eventually the moon.
Age and Growth of Earth
Scientists have managed to estimate the probable age of the Earth through radioactive decay procedure. Ernest Rutherford, a British scientist invented the process and utilized it in the early 1900s to ascertain the age of rocks and discovered that the Earth’s surface began its formation at around 4.4 billion years ago (Moore 27). Even the modern dating techniques have concluded that the earth could be approximately 4.5 billion years old. Using the same procedures, individuals can date fossils, stone-age tools, as well as meteorites and consequently reform the history of the solar system.
All the planets that constitute the solar system emerged from dust and gas that gathered around the sun’s proto-planetary disk (Wood 41). The combination of several mechanical sticking as well as gravitational disturbances, led to formation of large objects in the beginning of the solar system. Several model simulations indicated that once a combination of larger planetary embryos surfaced, they amassed quickly at the cost of smaller objects through dynamical friction and consequent gravitational pull. However, the final stages of Earth’s growth were moderately slow.
Earth became livable after undergoing geological evolution. When the breaking of debris halted, the Earth’s surface solidified, but left the surface covered with depressions. The geological time scale depicts Earth’s age in terms of 12-hour clock as shown below.
Figure 1: Geological Time as a Clock (Source: “Understanding Geological Time” 2)
In the beginning of Earth’s formation, there were no oceans or real atmosphere as the earth’s surface was almost recognizable. The radioactive decay contributed to the formation of oceans as well as the atmosphere, as the process eliminates the craters. Radioactive elements were involved in heating the planet from the inner side and the outer side. Consequently, the Earth melted and separated itself into circular-shaped layers as indicated in the Figure 2 below.
Figure 2: Earth’s Structure (Source: Erickson and Kusky 27)
The Earth consists of circular-shaped layers of materials, starting from the core. The Earth’s core is denser than its surface and this feature resulted to heavier elements being pulled towards the center while the lighter elements moved towards the surface (Erickson and Kusky 26). The process of profiling the core to the mantle took around 100 million years, leading to a formation of a molten planet.
During the geological evolution, radioactivity declines progressively with time, leading to slow cooling of the earth. The liquid material then re-solidifies to outline the solid core while the rest material remained in liquid form to surround the outer core. The earth’s magnetic field formed when the earth rotates the liquid material. When the liquid rock breaks through the crust, it discharges gasses into the atmosphere and the two common gasses discharged during the process include water and carbon dioxide. Since carbon dioxide can mix with water, it dissolves into the oceans where it later forms carbonate rocks that include limestone. The oxygen that accumulated in the atmosphere enabled the earth to sustain animal life (“Understanding Geological Time” 1).
Initially, the continents existed as one thin layer made of continental crust material, which was found under the ocean (Frederick 69). The process that pressured plate tectonics began when the heat flow originating from the Earth’s core found its way to the Earth’s surface. The plates were pushed across the earth’s surface using convection currents that originated from the upper mantle. After a powerful catastrophic event hit the Earth, much of the continental materials were exposed to the surface forming the foundation of the continents and creating the ocean floor (48). Looking at the global map, one can recognize that some continents seem to fit together, as if they were carved from the same spot as shown in Figure 3 below.
Figure 3: The Best-fit of the Present-day Continents (Source: Monroe and Wicander 32)
Alfred Wegener, who was a German meteorologist, developed the substantiation of the continental drift. According to Wegener, all land masses used to be a single supercontinent, which was named Pangaea, but a gigantic tidal force split the supercontinent into the present-day continents and pushed them to their present positions (Monroe and Wicander 31). The boundaries that formed between plates became regions of extreme geological activity where volcanoes and earthquakes developed occasionally.
After separation of plates into continents, the isolated plates continued to split, leading to formation of small islands. Mountains and valleys also developed from tectonic collisions. The shaping of plates led to animal adaptations in different environments. The fossil record also demonstrated the concept of continental drift. For instance, the remains of Mesosaurus, a reptile that lived in freshwater lakes, are only found in Brazil and South Africa (Monroe and Wicander 34). It was almost impossible for Mesosaurus to swim across the ocean and manage to locate a region that was identical to its previous habitat.
Formation of the Moon
Moon is the Earth’s only natural satellite, which came into existence 30 million years following the formation of solar system. Several theories exist to explicate the source of the moon. The most acceptable theory is the giant-impact theory, which asserts that the moon was formed after a gigantic collision between the Earth and a strange planet-size rock. According to Moore, the debris resulting from the collision formed a disk that orbited the proto-planet while the debris later underwent a process of condensation and collision growth to generate a satellite such as the moon (66).
Both the moon and earth contain abundant oxygen isotopes that bear the same composition. This indicates that they both formed from the same material. The material that went into the orbit after collision developed into moon through accretion. However, the collision seemed to have generated high temperatures that vaporized the water and eliminated the possibility of undergoing another process of accretion. When the moon condensed after accumulation of material from Earth and the strange planet-like rock, it moved closer to the Earth (Moore 67). The Earth contains a larger iron core than the moon, thus, enabling the moon to remain closer to Earth.
The formation of Earth incorporated numerous geological processes, which were also supported by biological processes. The origin of Earth can be traced from the solar system, where the spinning of cloud, which constituted interstellar dust and gases or solar nebula, resulted to collapsing and accumulation of dust and gas. The warming at the center of crust and the collision of dust and gas particles led to formation of proto-planets and Earth was part of the process. The moon was also formed almost at the same period as the Earth through accretion process. However, in recent years, significant improvement has been made concerning the study of Earth’s evolution, but scientists are still undertaking research on early Earth.
“Understanding important stages of geological time.” Elements of Geology, n.d. Web. 23 Feb. 2016 http://www.geoneed.org/wp-content/uploads/downloads/2011/05/Module-A1-Information-Sheets.pdf
Erickson, Jon, and Timothy M. Kusky. Asteroids, Comets, and Meteorites: Cosmic Invaders of the Earth. New York, NY: Facts On File, 2014. Internet resource.
Frederick Max B. How the Earth was formed. Raleigh, NC: Lulu Publishing, 2014. Print.
Monroe, James S, and Reed Wicander. The Changing Earth: Exploring Geology and Evolution. Belmont, CA: Brooks/Cole, Cengage Learning, 2009. Print.
Moore, Ben, and Ben Moore. Elephants in Space: The Past, Present and Future of Life and the Universe. Cham: Springer, 2014. Internet resource.
Wood, Bernard. “The Formation and Differentiation of Earth.” Physics Today 64.12 (2011): 40-45. Academic Search Premier. Web. 23 Feb. 2016.