Why Mars Has Other Colors Up CloseThe dust in the atmosphere causes Mars to appear very rusty from space. When viewed from the surface, other colors are apparent, in part because landers and other instruments don't have to peer through the whole atmosphere to see them, and partly because rust exists in colors other than red, plus there are other minerals on the planet. While red is a common rust color, some iron oxides are brown, black, yellow and even green! So, if you see green on Mars, it doesn't mean there are plants growing on the planet. Rather, some of the Martian rocks are green, just like some rocks are green on Earth.
Where Does the Rust Come From?So, you may be wondering where all this rust comes from, since Mars has more iron oxide in its atmosphere than any other planet. Scientists are not completely sure, but many believe the iron was pushed up from the volcanoes that used to erupt. Solar radiation caused atmospheric water vapor to react with the iron to form iron oxides or rust. Iron oxides also may have come from iron-based meteorites, which can react with oxygen under the influence of solar ultraviolet radiation to form iron oxides.
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