Understanding the Sun's Lifespan

The sun is expected to have an estimated lifespan of around 10 billion years, currently being approximately 4.6 billion years old. This implies that it has about 5 billion years left before it exhausts its hydrogen fuel. The sun primarily fuses hydrogen into helium, which releases energy, keeping it stable throughout its life. As the hydrogen in the core is used up, the sun will eventually transition into a red giant stage, dramatically expanding and altering its appearance before its eventual death.