What happens when the sun dies?

THERE’S PERHAPS nothing more ancient and unchanging than the sun, a yellow dwarf star that has illuminated Earth for over 4 billion years.

But our star, too, shall pass. And scientists are actually pretty certain about what will happen when it does. 

The sun powers itself by fusing, or combining, extremely hot hydrogen atoms inside its core. That creates helium and a lot of energy. But just as a music box will wind itself out, the hydrogen in the sun’s core will run dry. When that happens, in around 5 billion years, the sun will have to find a new power…