The demise of an ordinary star, on the other hand, occurs every year. By understanding how these garden- variety stars live and die, scientists are developing a clearer picture of our Sun's fate. Sun-like stars, like humans, are born, live their lives, and die. A sun- like star's life lasts about 10 billion years. The Sun's engine produces the heat that makes the Earth habitable.
Energy generated by the core also keeps gravity at bay.
All stars wage a continuous battle against gravity, specifically, the crushing weight of their outer layers. During most of a star's lifetime, pressure and gravity hold an uneasy truce. It is analogous to two people arm wrestling to a draw. The weight of the outer stellar layers pushes against a star's inner layers. This pressure exerts an outward force, like the pressure of gas in a hot air balloon, to combat the inward force of gravity.