What is the Sun?

 What is the Sun?

           Sun is one of the billions of stars that we see in the sky. It forms the nucleus of the solar system. All planets revolve around the Sun in elliptical orbits. It looks bright and big because of its proximity to the Earth than the other stars. It is at a distance of 150 million kilometres from the Earth. Its diameter is 13,92,000 kilometres, compared to the Earth's diameter of 12,756 kilometres. Its volume is approximately 1.3 million times more than that of the Earth. Even though it is gaseous, it weighs more than 300,000 times as much as the earth. It takes 8 minutes 20 seconds for its rays to reach the Earth.

            Like other heavenly bodies, the Sun is also not static. It, along with its family of nine planets, revolves around the Milky Way and takes about 225 million years to complete one revolution. It also rotates at its own axis. The temperature at its centre is approximately 15 million degree centigrade. The solar surface is composed of three gaseous layers. The innermost layer is called 'photosphere and has a temperature of 6000°C. The solar spots are seen in this layer.

            The next layer is 'chromosphere which is approximately 14,000 kilometres thick. This is composed of hydrogen, helium and other gases. The temperature of this layer is about 5000°C. The outer layer of the Sun is called 'corona'. 

            The Sun not only gives light to the Earth, but also gives life to its inhabitants. The Sun is the biggest source of heat and energy. Without it, life on Earth would not be possible.