What are red giants?

A red giant is like a balloon that grows really big when it gets old.

Imagine you have a balloon and you blow air into it, it gets bigger and bigger. A red giant is like that balloon, but instead of air, it's made of stars that are getting older and puffing out.

Stars start small, like little fireflies in the sky. They burn fuel called hydrogen, which keeps them shining. But as they get older, they run out of hydrogen and start burning a different kind of fuel, helium. This makes them expand, turning into big, red, glowing balls, that’s what we call red giants.

Sometimes, after being a red giant, a star will shrink down to something tiny, like a pebble in the sky, and that's called a white dwarf. But until then, it’s like a happy, big balloon, glowing brightly in space!