My very basic understanding of chemistry is you need an oxygen rich environment for something to be flammable. Hydrogen is flammable on earth because it combines with the oxygen in our atmosphere to cause a chemical reaction. Or something like that - I wasn’t very good at chemistry. I think earth is the only planet with a lot of oxygen because of the plant life that produces it. Or are you taking about nuclear explosion? Jupiter apparently is a failed star. It’s made up of the same elements as the sun but wasn’t quite big enough to produce the pressure and temperature needed to produce nuclear fusion and turn into a star.