Sun: The Ultimate Source of Energy
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| The Sun: Star |
Sun: The Ultimate Source of Energy
What is Sun?
The Sun is the only star in our solar system. It is at the centre of our solar system, around which all planets, drawf planets, asteroids revolve.The solar system and the sun was formed around 4.5 - 4.6 billion years ago. The sun is the main source of energy in our solar system (8 planets including the earth) it creates light photons which are basically like capsules of light and heat. Its diameter is 1.39 billion kms. It is so huge that one can fit 109 earth size planets inside it and its mass is 330000 times that of the earth. It mainly consists of Hydrogen and helium (73% and 25% respectively), with minor amounts of oxygen, carbon, neon and iron. It accounts for about 99.86% of the total mass of the solar system.
How was it formed?
The journey of the Sun started from the giant rotating nebular cloud (mixture of gases mostly Hydrogen and helium), in the past suddenly due to the shock wave from the near by supernova, the nebular cloud compressed at some places and formed the centre of star formation. In the initial phase the compression lead to the formation of denser centres in the nebular cloud. These centres became the kitchen for the formation of the sun(Star). Due to the contraction the cloud started to rotate faster and most of the mass concentrated towards the centre and the cloud stretched into a form of nebular disk.These denser parts in the nebular cloud attracted near by matters towards them due to gravitational pull of the masses. The attraction of nearby matter into the centres and their compression lead to increase in pressure and thus increase in temperature. As the temperature of the core started to rise above a critical temperature, the Hydrogen in the core underwent nuclear fusion, which is the process by which smaller atoms combine to form heavier elements . This lead to further increase in temperature, as a result of large amount of energy released during the process of fusion. This with the continues increase in temperature due to fusion increased the surface temperature of the sun and formed Helium as a result of this fusion. Thus the sun became centre of the solar system due to heavy weight accumulated during the initial stage of its formation. The left out part of the solar nebula continued to rotate around the newly found sun. This solar nebular slowly cooled and formed the various planets revolving around the sun.
How are terrestrial planet formation different from Juvion Planets?
The region near the sun was too hot for the gasses to condense due to high temperature near the sun. Also the solar winds caused due the sun carried gases away from the sun. Thus near the sun only elements with high boiling temperature condensed and formed the Terrestrial planets (Mercury, Venus Earth and Mars )constituting Lead (Pb), Iron (Fe), Magnesium (Mg), Silicon (Si) etc. The gases with lower boiling temperature condensed away from the sun. Also the gases swept away from the terrestrial planets by the solar winds condensed and formed the gas giants (Jupiter, Saturn, Uranus and Neptune).These are called gas giants or Jovian planets due to their large sizes and they are mostly formed of H, He and other gases.
How does it power our planet earth?
The heat and light produced during the nuclear fusion in the sun travels through the space entres our atmosphere. These energy capsules are called photons. They are absorbed by the green leafy plants by the process of photo-synthesis. These plants use water from soil, CO2 from atmosphere and in presence of sunlight they convert energy in the form of glucose (energy packets of the plant) store them and oxygen is released in thermosphere as a by-product.
These plants are subsequently eaten by herbivorous/omnivorous animals such as goats, cow, bear etc. which provide them energy thus plants are called primary producers. The food eaten by the animals are digested and by the breakdown of glucose give energy to their body. Thus animals are called primary consumers. The herbivorous plants are eaten by secondary consumers (carnivorus) animals. Thus the energy stored in the body of primary consumers is transferred to the bodies of secondary consumers such as Lions, Tigers etc. Only 10% of the energy stored in one level is transferred to the next level.
Energy in the form of fossil fuels?
The plants when they are buried for millions of years they transform into coal( fossil fuel) and when they are ignited they produce energy which has been stored in them while they performed photosynthesis millions of years ago. Similarly the microscopic algae organisms living on the surface of oceans and lakes millions of years ago they capture the sun energy by photosynthesis by the same process as it happens in the plants. When these organisms die they drop to the bottom of the sea floor and get buried under the layers of sediments. This process continues for millions of years. During this process due to increase in pressure due to over burden sediments and the temperature due to the geothermal gradient these micro organism become hydro-carbon oil and gas. These precious fossil fuels are extracted to the surface of the earth, refined and processed.. Are then used to run the automobiles , industries. Thus powering the economies.
How does it power the atmosphere and the hydrosphere?
The heat generated by the sun falls on the surface of the earth and heats up the earth, the different rates of heating of the sea surface and land causes land and sea breeze to flow.
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| Setting Sun at sea beach |
Land Breeze: Simillarly during the night after the sun has set now the land starts to cool faster than the sea . Thus now the sea is relatively hotter than the land . Thus the air above the sea surface heats up and rises. This gap is filled by the wind blowing from land to the sea . Thus is called the sea breeze.
The sun heats up different parts of the earth at different rates thus it causes winds to blow and sets up atmospheric circulation. The sun rays falls almost directly over the area near the equator, thus these areas receives higher energy as compared to the poles where the sun rays fall on the surface of the earth at an angle. Thus the same amount of energy is distributed over a larger region and thus energy per unit area is reduced. As a result these areas are colder as compared to the equatorial regions. Thus the air above the equator gets heated up and rises this gap is filled by the wind flowing from the higher latitudes. This forms the basis of atmospheric circulation.
Similarly, the differential heating also takes part in the ocean bodies and causes thermo-haline circulation, which is basically a conveyer belt system within the ocean which redistributes the ocean water.
Thus we can easily come to the conclusion that the sun is the basic source of energy for all the forms of energy on earth.
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