Well, Cody, Jupiter is the largest planet in our solar system. So Jupiter is really big compared to Earth and all the other planets. But Jupiter is still small compared to the sun. It's about a thousand times less massive than the sun. Jupiter isn't massive enough to be a star.
Stars have to have enough mass to get hot enough inside to spark thermonuclear fusion reactions.
Cody, thanks for your question. Our show is made possible by the National Science Foundation. You'll hear about everything on the Earth . . . On Kids' Earth and Sky.