Sun is a huge ball of mass with glowing gases around it. it is the heart of the solar system that keeps our solar system combined. the planets are revolving around the sun due to the gravitational pull of the sun. The sun illuminates light and heat in a larger amount. The light travels a long distance to earth i.e 151.51 million km far. The heat produced in the sun is of much higher intensity than we feel on earth. But have you ever realized how the sun realizes such a higher amount of heat?
The answer to the question lies in the concept of nuclear fusion. Sun is a huge mass with hydrogen protons at the core. The core undergoes nuclear fusion reaction to produce energy. The sun is the ultimate source of energy in our solar system. The nuclear fusion that occurs in the sun is proton-proton fusion. But how now the question may arise how could a proton fuse with another proton without getting repelled. The columb force states that the same charges repel each other and both the protons are positively charged. But there lies a fact that the nuclei of the hydrogen atom are the smallest nuclei among all the elements. the short-ranged nuclear attraction is much much stronger than the columb force of repulsion. Thus the protons fuse and while fusing they eliminate a larger amount of energy in the form of heat and light. the hydrogen atom is converted to helium with two protons. but what would happen if all the protons get combined and turn into helium? Will the sun start cooling? The answer to this question is preferably no because the cycle of nuclear fusion is continuous within the sun. Most of the time the formed helium ion breaks into protons again but sometimes one of the protons transforms into a neutron via the weak nuclear force. Along with the transformation into a neutron, a positron and neutrino are formed. This resulting proton-neutron pair that forms sometimes is known as deuterium. Deuterium is a heavy isotope of hydrogen. A third proton collides with the formed deuterium. This collision results in the formation of a helium-3 nucleus and a gamma-ray. These gamma rays work their way out from the core of the Sun and are released as sunlight. Two helium-3 nuclei collide, creating a helium-4 nucleus plus two extra neutrons. Technically, beryllium-6 nuclei form first but is unstable and thus disintegrates into the helium-4 nucleus.
The energy produced in the sun has to travel many layers in the photosphere before it comes out as sunlight. It is to note that 99% of the energy produced in the sun is produced in the core. The rest of the Sun is heated by energy transferred outward from the core. The proton-proton chains occur frequently at – 9.2 x 1037 times per second. Among all the mass undergoes fusion, only 0.7%of it is turned into energy. It may seem to be less amount of energy but this is equal to 4.26 million metric tonnes of the matter being converted to energy per second. From the einsteins mass-energy equivalence it equal to 4.26 million metric tonnes of the matter is equal to about 3.8 x 1026 joules of energy released per second.