Why do stars appear to be collapsing ?

Stars appear to be collapsing due to the effects of gravity. Gravity is a fundamental force of nature that causes all objects with mass to be attracted to each other. In the case of stars, the enormous mass of the star creates a powerful gravitational field that causes it to collapse inward.

As a star burns through its nuclear fuel, the heat and pressure generated by the fusion reactions counteract the inward pull of gravity, keeping the star in a stable equilibrium. However, when the star exhausts its nuclear fuel, it can no longer generate enough energy to counteract the force of gravity. At this point, the star will begin to collapse inward.

As the star collapses, its core becomes denser and hotter. Eventually, the core becomes hot enough to ignite a new round of fusion reactions, which release a burst of energy that causes the outer layers of the star to expand outward in a violent explosion called a supernova. The final fate of the star depends on its mass; smaller stars will eventually become white dwarfs, while larger stars may become neutron stars or black holes.

So, while stars may appear to be collapsing, it is actually a natural process that occurs as the star reaches the end of its life cycle.