The story of the red planet, it turns out, may be due for a revision. At one time, experts thought that Mars was covered with fields of rocks with iron trapped inside. Somehow or other, and over a long period, those rocks reacted to water in the air. That reaction formed rust, in much the same way it does when iron and water meet on Earth. Then, over billions of years, those rocks slowly eroded. As they broke down into dust, heavy winds spread the scarlet silty substance all around, until Mars’ entire surface was coated with it.
But a new study in Nature Communications instead says that water covered much — perhaps all — of its surface. That liquid quickly reacted to the iron in the planet’s many rocks. As the water receded, then disappeared, those rocks turned into dust, which then covered the entire planet.
"One of the most exciting aspects of this research was how it contradicted the prevailing theory about Mars' red coloration," says Adomas Valantinas, an author of the paper who participated in the study while at the University of Bern in Switzerland. He is now a research fellow at Brown University in the U.S.
