ELI5: How does the sun produce energy?

Imagine the sun as a giant, super-heavy ball way, way out in space. This ball is made mostly of a gas called hydrogen.

Now, because the sun is so heavy, everything inside it is squished together really tightly. This squishing creates a lot of heat. Think about rubbing your hands together really fast - they get warm, right? It's like that, but way more intense inside the sun.

Because of this extreme heat and pressure, something cool happens. The tiny bits that make up hydrogen, called protons, start bumping into each other really hard.

When these protons smash together with enough force, they stick together and change into something different: helium. This is called nuclear fusion.

• It's like taking four LEGO bricks and smashing them together to make one bigger, slightly different LEGO brick.

• Remember Einstein's famous equation, E=mc^2? It basically says that mass and energy are the same thing, just in different forms.

So, the sun makes energy by:

• Squeezing hydrogen atoms together really hard.
• Smashing them together to make helium.
• Turning a tiny bit of the hydrogen into energy during the process.