Large balls of gas that create and emit their own radiation are called stars.

Here's why:

* Gas: Stars are primarily composed of hydrogen and helium, which are gases.

* Large: Stars are massive celestial objects, much larger than planets.

* Create and emit their own radiation: Stars generate energy through nuclear fusion, a process where hydrogen atoms fuse to form helium, releasing immense amounts of energy in the form of light and heat.

Let me know if you have any other questions!