Here's a breakdown:

* Inward Force: Gravity pulls all the star's mass towards its center. This is a constant force trying to collapse the star.

* Outward Force: The internal pressure is generated by nuclear fusion reactions happening within the star's core. These reactions release tremendous energy that pushes outward, resisting the inward pull of gravity.

Stellar equilibrium is a dynamic balance:

* Stable Stars: Most stars spend the majority of their lives in a state of stable equilibrium. The forces are perfectly balanced, meaning the star neither collapses nor explodes.

* Unstable Stars: When the balance is disrupted, stars can either collapse into denser objects (like white dwarfs, neutron stars, or black holes) or explode as supernovae.

Key takeaway: Stellar equilibrium is the delicate balance between the crushing force of gravity and the outward pressure generated by nuclear fusion that allows stars to exist and shine.