GENERAL KNOWLEDGE

Detailed explanation-1: -When the young star runs out of hydrogen, its core will once again begin to collapse. The extreme forces on the core causes it to heat up. Soon, the core is hot enough that it can begin to fuse helium into carbon and oxygen. Once again, nuclear fusion pushes back against gravity to prevent the star from collapsing.

Detailed explanation-2: -Since iron does not act as a fuel, the burning stops. The sudden stoppage of energy generation causes the core to collapse and the outer layers of the star to fall onto the core.

Detailed explanation-3: -Once a star has exhausted its supply of hydrogen in its core, leaving nothing but helium, the outward force created by fusion starts to decrease and the star can no longer maintain equilibrium. The force of gravity becomes greater than the force from internal pressure and the star begins to collapse.

Detailed explanation-4: -All stars eventually run out of their hydrogen gas fuel and die. The way a star dies depends on how much matter it contains – its mass. As the hydrogen runs out, a star with a similar mass to our Sun will expand and become a red giant.