The process of formation of the Earth
The process of formation of the Earth-Earth is not a thing in the universe that presented itself was in perfect shape. Earth was formed through a long process and continue to grow and to form today. The scientists found that the process has been started since the establishment of the Earth billions of years ago. Planet Earth originated from a giant cloud in space that is always spinning. Giant clouds will form an attractive balls of dust grains and gas. Balls of dust and gas is the beginning of the formation of the Earth, the planets, as well as other months.
When the greater gravity, gas and dust will be compressed and increasingly congested. This causes the Earth is getting hotter and a glowing ball. The outside of the Earth gradually began to cool and harden. But the Earth has not been cold at all. The central part of the Earth is very hot. The process of formation of the Earth is almost the same as the Kant-Laplace opinion that suggests that the Earth is beginning to take shape during the billions of years ago when released from the sun in the form of incandescent gas, which gradually cools and form a crust rocks.
Although many theories or opinions of scientists about the formation of the Earth, but no one who profoundly knows exactly how and when the Earth was formed. Yes, a challenge for the scientific world that one day you can solve.
The process of development of the planet Earth from time to time can not be separated from the history of the formation of the solar system. This is because the Earth is one of the family members of the Sun, in addition to other planets, comets, asteroids, and meteors.According to the nebular hypothesis (theory of cold gas clouds) that was developed by a German philosopher, Immanuel Kant (1755) and the French astronomer, Pierre Simon, Marquis de Laplace (1796), indicated that the solar system originated fromgas mass (cold gas clouds) that glow and spin slowly.
The mass of the gas gradually cooled, shrink, and approximates the shape of a ball. Therefore, the gas mass rotating at speeds greater and higher, at the equator (equator) receive the greatest centrifugal force, the mass eventually ballooned. End of the bulging parts, some parts are removed (knocked out), and form the incandescent balls of different sizes from each other. Mains gas mass eventually became the Sun, while the small balls are separated from the parent mass cools eventually became the planets, including Earth. At the time regardless of the mass of the parent, the planets in the solar system is still an incandescent bulb with a very high temperature. Because the planet rotates, there are parts of his body apart and rotated while circulating around the planet. The next object is called the Moon (natural satellites).
According to the research results of experts on astronomy and geology, earth or apart from the body formed the Sun about 4.5 billion years ago. Estimates are based on the birth of Earth review of Paleontology (the study of fossils of ancient beings rest in the past) and stratigraphy (the study of the structure of the rock layers forming the face of the Earth).
Figure 2.13 Cycle Planet Formation
Illustration of Earth formation cycle is divided into:
(A) the Earth was spherical bulb;
(B) the Earth cools gradually formed the lithosphere;
(C) the formation of the Earth's atmosphere;
(D) the Earth formed.
At the time of birth some 4.5 billion years ago, Earth is still a very hot incandescent bulb. Eventually gradually our Earth cools. As a result of the cooling process, the outer layer of the Earth froze to form the Earth's crust is called the lithosphere. Besides freezing the Earth's crust, the mass of the Earth's cooling led to the evaporation of gas on a large scale into the sky. This evaporation process occurs in a million years that the accumulation of vapors and gases that very much.
At this point begins to form the Earth's atmosphere. Accumulated water vapor in the atmosphere over millions of years eventually dropped back as rain for the first time on Earth, with high intensity and in a very long time. Drops of rain were falling further fill the notches formed Earth spans seas and oceans.
A weather scientist from Germany named Alfred Wegener (1912), the well-known theory, the Theory of Flotation Continental (Continental Drift Theory) suggests that up to about 200 million years ago, on Earth there is only one continent and oceans are vast. This giant continent called Pangea, whereas the flanking region called Panthalasa ocean.
Little by little Pangea suffered cracks and broken. Around 180 million years ago, giant continent broke up into two fragments continent called Laurasia in the north and in the south called Gondwana. The two continents are separated by a narrow sea lane called Tethys Sea. The rest of the Tethys Sea at a point on the Earth's oil deposits around the seas in the Middle East.
Figure 2.14 Continental Drift Theory of Continental Drift theory of Alfred Wegener regarding the formation of the Earth's land mass.
Both Laurasia and Gondwana in the then divided again into smaller land and move irregularly with velocity ranging between 1-10 cm per year. In the history of planet Earth, Laurasia was the forerunner of continents that are currently located on the north equator (northern hemisphere), covering Eurasia, North America, and the surrounding small pulaupulau. The Gondwana is the origin of the continents in the southern hemisphere, including South America, Africa, Indian Sub Continent, Australia, and Antarctica.