The Rusting Planet

Identification of Mars as “the Red Planet” is common knowledge even for non-astronomers, and its color is known to stand out to the sky gazer’s naked eye. But despite the association, Mars may not have always been red, researchers announce.

Research by scientists presenting at the European Planetary Science Congress disputes the previous idea that the red was essentially rust leftover from when liquid water ran on mars, forming iron oxide on the surface. However, NASA Mars rovers Spirit and Opportunity found evidence of certain minerals on Mars’s surface that would have been destroyed by water—suggesting perhaps that the surface water idea just doesn’t float.

The scientists proposed an alternative mechanism to explain the red color: plain, old-fashioned erosion acting on magnetite. (Magnetite is an iron oxide that exists on Mars.) To test the idea, they used a machine to tumble grains of quartz sand grains. The tumbling produced an erosive effect that led to ten percent of the sand becoming dust in just seven months. As more and more of the grains eroded, the dust increasingly stained the sand red.

The chemistry behind the coloring effect lies in the disrupted chemical bonds as sand grains are eroded. Oxygen is transferred from the quartz to the magnetite, forming hematite and reddening the dusty environment.

Jonathan Merrison of the Aarhus Mars Simulation Laboratory commented that the hypothesis may better explain Mars’s color if surface water wasn’t common as once thought. As for how the process may alter the timeline of Mars’s coloration, Merrison added, “Before this work, I think most people in the field kind of thought the Martian surface was billions of years old and had always been red. This work seems to imply that it could be quite recent—millions of years instead of billions of years.”

Merrison’s “quite recent” is still far too old for young-earth creationists, but it does provide an avenue for further research—into the length of time such a process would take to stain the entire planet (though such research might still be predicated on uniformitarian assumptions).