Stellar fusion

Stellar fusion is the process by which stars produce energy by combining lighter atomic nuclei, primarily hydrogen, into heavier elements like helium. Under extremely high temperatures and pressures in a star's core, these nuclei move rapidly and collide with enough force to fuse together. This fusion releases a tremendous amount of energy in the form of light and heat, which balances the star’s gravity and prevents it from collapsing. Essentially, fusion is the engine that powers stars, allowing them to shine over millions to billions of years.