Does metal rust in outer space?

Sort of. Rusting in outer space doesn’t happen in quite the same way it does on Earth due to differences in the amount of available water. On Earth, iron rusts when it interacts with water molecules causing oxidation of some of the metal atoms to metal oxides. Recalling this information, it is clear that some source of oxygen atoms must be present for metal to rust! There is very little oxygen or water floating around in outer space, so the reaction doesn’t proceed as quickly or via the same mechanism. Actually, in outer space, the very small amounts of oxygen (O2) or water (H2O) that are around are believed to undergo photochemical reactions with metals to produce metal oxides, like rust (Fe2O3). Scientists can get a sense of how rapidly metals rust in outer space by looking at iron-containing meteorites that reach the Earth.


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