Verified answer

All the time - gravity is constantly making it collapse under its own weight.

At the same time the heat generated by thermonuclear reactions taking place within its core makes it expand.

The net result is that the Sun is going to be roughly stable for the next 5 billion years. Then its core will collapse and the outer layers expand.

Sun will become a red giant after 5 billion years.loose the external gas to space and will become a white dwarf.

after 500 milliard year