Tuesday 19 February 2013

The Sun And Its Importance To Planet Earth

By Haywood Hunter


There exist billions of stars in the sky. Among them, the Sun is the closest to the earth. The sun lies in the middle of the solar system. It makes one rotation every 27 days. Formed about 4.5 billion years ago, it is assumed to be in its midlife. It is expected to continue shining for about five billion more years.

Photosphere is the name given to the surface of the sun. The temperature at the core of the sun is 15.7 million K, a lot hotter than the photosphere's 5,778 K. This energy is produced via a nuclear reaction called nuclear fusion. During this process, two hydrogen nuclei bond to make one helium nucleus. This process involves release of energy.

The distance from the Earth to the sun is 149.6 million kilometers. The diameter of the sun is 1.392 million kilometers. It has an equatorial circumference of 4.379 million kilometers. These measurements represent 109 times the corresponding measurements of the earth. The sun has a surface area of 6.0877 trillion kilometer squared, about 11,990 times that of the earth. It has a volume 1.3 million times that of earth.

The heat from the sun reaches the earth through radiation. This energy is known as solar energy. Note that the planet absorbs only a small portion of this energy, the rest is reflected back to space. The absorbed heat is responsible for life on earth. It is also the source of the earth's climate, wind trends and water cycle.

Through photosynthesis, plants utilize solar energy to make their own food. All other living organisms on earth depend on this food to survive. Energy stored in fossils, as well, result from effects of the sun. This includes coal and petroleum.

The sun is earth's basic source of energy. This energy reaches us in two main forms, light and heat. Solar energy is also applied in promoting plant growth in green houses, solar lighting and powering electronic devices. There cannot be life on earth without the sun.




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