When we hear people talk about “pollution,” we generally assume they’re talking about pollution on Earth. Slogans like “There is no Planet B,” “Go Green,” or “Save the Earth,” are meant to warn people that we only have one habitable planet, and we have to cut back on our waste and pollution and use renewable energy sources to keep it habitable. However, pollution exists off-world, too, and it’s a bigger deal for our Earth than you might think.