If Jupiter is made mostly of hydrogen, could we destroy the planet if we put it on fire? Why doesn’t it spontaneously burn up when lightning strikes?

Q: A man is in a dark room that contains only hydrogen gas. He tries to light an ordinary match. What happens?

To nothing. A match will not burn without oxygen.

Jupiter is much like a room filled with hydrogen gas. If you exposed it to “fire”, there is nothing for the hydrogen to react with.

When the remnants of the Shoemaker-Levy 9 debris hit Jupiter in 1994, some very interesting things about Jupiter were observed. Like, a fire giant.

Essentially, these cometary fragments pierced Jupiter’s atmosphere, which astronomers expected would lift material from beneath the upper layer. What they would then observe to better understand the interior of Jupiter.

And they saw things, like ammonia and sulfur. But there is no sulfur dioxide. Which would indicate that presence of oxygen that had reacted with the sulfur.

Furthermore, it suggests that there simply isn’t much oxygen on Jupiter. There is surely a small amount of water vapor. And that could come from many sources. And if some oxygen were to react with hydrogen, we would expect water vapor as a result. But we don’t see much water vapor on Jupiter either.