Dr. Nimmy John V
Most probably Sun would have been our first drawing, a circle with spikes, we would have given bright colors like red, orange and yellow. The whole life on earth depends on our first drawing, “The Sun”. The sun we see is not just a sphere with bright color, it undergoes furious explosion inside itself to form a massive fire ball composed of gases. This massive gaseous fire ball, started burning 4.5 billion years ago and it’s still burning. The temperature of sun at its center is 15 million degree celsius and at the surface 5500 degree celsius. The sun has an inner layer and an outer layer. The inner layer includes core, radiation zone and convection zone and the outer layer include photosphere, chromosphere and corona. Sun act as a gigantic nuclear reactor which undergoes some special types of chemical reactions in a controlled manner.
What is happening inside the sun to produce enormus heat and light? which fuel is burning the sun? Sun is composed of different elements such as hydrogen, helium, carbon, sulphur, neon etc. Astronauts explain that, the gravitational force inside the sun create immense pressure and temperature, this gravity pulls the materials to its center and hence adopt a spherical shape. 91% of sun is composed of hydrogen gas, which is the fuel that produce heat and light. Hydrogen gas at 15 million degree celsius, converts to plasma state; the fourth state of matter. Negatively charged electrons are completely isolated from positively charged nucleus in its plasma state and undergoes a special type of chemical reaction, termed nuclear reaction. The element hydrogen has different isotopes; Isotopes are elements having same atomic number but different mass number. Isotopes of hydrogen, deuterium (1H2) and tritium (1H3) are squeezed and fused together at very high temperature and pressure to produce helium (2He4) and neutron. In this reaction hydrogen atom is changed to helium, which means that the nucleus of the atom is been transformed, this type of reactions is called nuclear fusion reaction. Tremendous amount of energy is being released as heat and light during this process. The heat produced at the core of the sun takes millions of years to reach its surface. The heat and light will be radiated through the corona layer and thus reach the earth surface, which attributes to almost all mechanism that drives the life on earth.
