Did you know that the sun will eventually burn out and die?

When that happens, sadly, the earth will die to. Like all stars, the sun is basically a giant nuclear reactor that burns hydrogen to create energy. But like any reactor, the sun needs fuel to keep going. It's been going strong for around four-point-five billion years, and will probably keep burning for about five billion more. By that time, it's fuel will run out.

When the fuel runs out, gravity will cause the sun's core to contract. When it contracts the core will get hotter, which will heat up the sun's upper layers and make them expand. The sun will then become what's called a red giant, and its radius will reach just past the orbit of Venus.

To put it bluntly, we'll be burned to a crisp. After a few billion years the core will begin to cool and expand. The sun's upper layers will expand and lose material, and eventually the core will cool enough to become a white dwarf star, and finally a black dwarf.

We're pretty much doomed, but not for billions of years.