Fire exists on Earth only.

 Fire exists naturally only on Earth because it needs three things—fuel, oxygen, and heat—all of which are uniquely present in the right balance here. In the vacuum of space or on other planets with different atmospheres, such as Mars with its carbon dioxide-rich air, fire cannot ignite or sustain itself. Even the Sun, though it burns intensely, is not fire in the traditional sense; it is a massive ball of plasma powered by nuclear fusion, not combustion. Without Earth’s specific conditions, natural fire simply cannot exist.