What balance marks the end of a star's birth process and the beginning of its long, stable life?

Answer

Hydrostatic equilibrium

Hydrostatic equilibrium is reached when the powerful outward thermal pressure generated by core nuclear fusion perfectly counteracts the relentless inward pull of gravity, stabilizing the star.

What balance marks the end of a star's birth process and the beginning of its long, stable life?

#Videos

The Life Cycle of Stars - YouTube

astronomystarsstellar evolutionformationstar formation