Question

The hydrostatic equilibrium is often referred to as "battle between pressure and gravity". Explain how does this help us understand the strcture of stars.

Answer 1

A star has core and outer surface photosphere in case of our Sun. The core of a star attract the outer surface due to high gravity. Gravity acts towards the centre of a body. In this way outer surface should be collapse inside the star but this is not the case in living star. There is another force and that is radiation pressure generated by energy produced ny nuclear fusion in core of a star. This pressure acts outwards and balance gravitational force. Hence there is a kind of battle between pressure and gravity.