The Earth In The Beginning ,Continental Drift Theory

The Earth In The Beginning

When the Earth was formed the entire planet was filled with the erupting volcanoes and smoke. The lava was scattered all over the surface of the Earth which looked like a red hot ocean. This lava rose  up in the air and circulated in the atmosphere. The hot gases that erupted from the lava were highly poisonous. Around one billion ears later, the poisonous air cleared out from the atmosphere and the water vapour present in the clouds fell on the Earth in the form of rain. Thus, oceans and other water bodies were formed. Gradually, the Earth began to cool down and the oceans of lava hardened to from its crust

Continental Drift Theory

 According to the continental drift theory, the world was made up of  one single continent known as Pangaea. The single continent slowly disintegrated and its parts drifted apart from each other forming into the seven continents. The theory of continental drift was suggested by a German meteorologist named Alfred Wegener in 1912. According to him the position of the continents to him are not fixed at a certain place and are gradually moving at a rate of about one yard every century.

The Earth In the Space

 The Earth is one of the eight planet that move around the Sun, It is the third planet from the Sun. Yuri Gagarin was the first person to see the Earth from the Russian rocket Vostok on April 12,1962. He said “ I can see the Earth. It is so beautiful. “During early days, Unnamed craft satellites used to orbit the earth spins as it moves through the space, once in every 24 hours, thus we experience day and night. Apart from this, it is slightly titled on its axis. This cause the seasons. The atmosphere of the earth has plenty of liquid water and oxygen, which is essential for life.

Earth’s Satellite

The Earth has only one natural satellite, the Moon. It spins on its axis in 27.3 days and takes the same time to complete one orbit around the Earth. As the moon orbits the Earth, It changes its shape. The changing shape of the bright part of the moon is known as different phases of the moon. Moon does not have its own light, but reflects thee light of the Sun. A part from the Moon, the earth also has many  artificial satellites. These artificial satellites have been especially stationed to orbit the earth and bring  useful information regarding our planet. They help in weather forecasting and replaying  television and telephone signals around the world. The space age began with the launch of Sputnik in 1957.

 

Inside the Earth

 The structure of the earth is very simple. The earth is divided into three layers; the crust, the mantle and the core. All the continents and the seas rest on the outer layers of  the earth known as the crust. Under the crust lies the  mantle, which slowly moves  the huge  parts of  the crust known as continental plates.  Right in the middle of the Earth is  the core.

   CRUST

 Crust is the outer layer  of the  Earth.  It is divided into two parts, the oceanic crust and the continental crust.  The oceanic crust is the crust below the oceans. Most of its part is made up of  tholeiitic  basalt, whereas continental crust is made up of  tholeiitic  basalt, whereas  continental crust is made up of igneous rocks.

Mantle

Mantle is that layer of  earth, which is located  above  the core. It is divided into inner mantle and outer mantle. The inner mantle is found between 300km -2890km below the surface of the earth. This part is made up  silicon and magnesium. The outer mantle is thinner than the inner mantle and is found between 10km-300km below the earth’s surface.

Core

Core is the  inner part of the earth. The core  is 3,550 km below the Earth’s surface. It is divided into inner core and outer core. The outer core is probably liquid and the inner core is solid. It is made up of iron and nickel. The  inner core is 5,150-6,370 km below the surface of the Earth whereas the outer core is 2,890-5,510 km below its surface. The core is the hottest part and emits some heat to the upper layer in the form of currents known as convection currents.

Composition Of  Earth

Most of the Earth consists of iron, oxygen , silicon and magnesium. The crust of Earth is made up of silicon and oxygen, together known as silicates. Small amounts of calcium and aluminium are also found in the Earth’s crust.

The Earth’s Atmosphere

The  Earth’s atmosphere consists is made up of three main gases: oxygen, nitrogen and argon. A part from these gases, other gases are also present in small quantities. It also contains dust, pollen and water . Atmosphere plays a vital role in protection us from the solar and cosmic radiations and bombardment by meteors and extreme temperature. It is the earth’s gravity that holds the atmosphere in its place.

Layers Of The Atmosphere

The Earth’s atmosphere consists of mainly five layers: Exosphere, Thermosphere , Mesosphere, Stratosphere and Troposphere. Exosphere: It hardly contains any gas. It is the uppermost layer.

 Thermosphere: Thermosphere is the layer of the atmosphere where we can see the space satellites orbiting the Earth’s surface.

 Mesosphere : Mesosphere is the layer of atmosphere above the troposphere and stratosphere and below the thermosphere.

 Stratosphere : Stratosphere is the layer of atmosphere above the troposphere. The tropical and mid-latitudes of stratosphere contains ozone  layer. This layer blocks all the harmful ultraviolet radiations. This layer provides ideal conditions for flying aeroplanes.

Troposphere : Troposphere is the lowest layer of atmosphere. All Phenomena of climate and weather take place in this layer.

Composition Of Air

The basic element  of air are nitrogen and  Oxygen, with small amount of argon. The three main gaseous elements account for about 99.9% of the total atmosphere. They exist in constant proportion: nitrogen comprises 78% of air by volume, oxygen comprises 21% of air by volume and argon comprises  0.9% of air. The remaining 0.1% of the atmosphere consists of water vapour, carbon dioxide, ozone, methane and various oxides of nitrogen, neon and helium.

Atmospheric Circulation

 The atmosphere circulation transfers heat to and from the equator by a series of convection cells. Earth has three circulation cell in each hemisphere. The initial cell called Hadley cell transfers warm air towards north over the tropics. The second cell is Ferrel cell. The temperature latitudes are regulated by ferrel cell. The third one is the polar cells which are found at both the poles.