The Sun is a star at the centre of our Solar System and is one of the most important source of energy found on earth. A star is born when atoms of light elements are squeezed under enough pressure for their nuclei by fusion process and their life are the result of balance of forces: the force of gravity constantly works to try the star to collapse. The star's core is very hot which creates pressure within the gas. This pressure hinders the force of gravity, putting the star into hydrostatic equilibrium. Different stars take different paths for their life cycle depending on their mass. Though stars shine for many thousands, and even millions of years, stars do not last forever, they also die!. The changes that occur in a star over time and the final stage of its life depends on a star's size. Star, Neutron star, white dwarf also has a limiting value.