Our sun isn't massive enough to trigger a stellar explosion, called a supernova, when it dies, and it will never become a black hole either. All the outer material will dissipate, leaving behind a planetary nebula.

Once all the helium disappears, the forces of gravity will take over, and the sun will shrink into a white dwarf. That element will then fuse into heavier elements, like oxygen and carbon, in reactions that don't emit as much energy. Then, the hydrogen in that outer core will deplete, leaving an abundance of helium. That's when the sun will become a red giant, which it will remain for about a billion years. Our star will grow to be larger than we can imagine - so large that it will envelope the inner planets, including Earth. Gravitational forces will take over, compressing the core and allowing the rest of the sun to expand. With no hydrogen left to fuse in the core, a shell of fusion hydrogen will form around the helium-filled core, astrophysicist Jillian Scudder wrote in an article for The Conversation (opens in new tab). Once all the hydrogen gets used up, the sun will grow out of this stable phase. Our star is currently in the most stable phase of its life cycle and has been since the formation of our solar system, about 4.5 billion years ago. The battle between gravity and the energy from fusion reactions fuels our sun and billions of other stars in our galaxy and beyond.īut in about 5 billion years, the sun will run out of hydrogen. Those naked hydrogen atoms then fuse together into helium atoms, and that reaction releases enough energy to counter the intense pressure of gravity collapsing the cloud of gas.

Sun turning into a black hole