A recent study has claimed that Mars is red in color due to ferrihydrite, an iron oxide mineral that’s left over from liquid water. This finding suggests that the Red Planet could’ve had a cold and wet, but habitable past. The ferrihydrite study was done in controlled lab environments recreated using Mars orbital and ground-level data from previous NASA and ESA (European Space Agency) missions. The research team is also relying on the Perseverance rover returning sample to Earth to verify the findings.
Thanks to NASA and foreign space agency missions, we can conclusively say that Mars had a great amount of liquid water at some point in its ancient history. Over billions of years, presence of water had carved out what look like rivers and lakes (and even oceans and its beaches) on Mars’ surface. A recently published study is adding more detail to the picture by suggesting that the red iron oxide dust that makes up Mars’ signature color stems from ferrihydrite, which only forms in the presence of cool water. The researchers in this study believe that Mars might thus have had an environment capable of sustaining liquid water (and potentially life).
The research team isn’t the first to propose the ferrihydrite theory, but it’s the first to test the idea using a combination of prior Mars observational data and laboratory methods to create Martian dust in the lab. Tapping into data from a multitude of Mars missions—such as NASA’s Mars Reconnaissance Orbiter, ESA’s (the European Space Agency) Mars Express and Trace Gas Orbiter, and NASA rovers like Curiosity, Sojourner, and Opportunity—especially spectral information of Mars’ surface, the team was able to make comparisons to lab experiments that tested how light interacted with ferrihydrite particles (and other minerals) under simulated Martian conditions.
Lead author Adam Valantinas, a postdoctoral fellow at Brown University, Rhode Island, said that, “What we know from this study is the evidence points to ferrihydrite forming and for that to happen there must have been conditions where oxygen from air or other sources and water can react with iron. Those conditions were very different from today’s dry, cold environment.”
However, this proposed idea can only be definitely tested once sample from Mars are returned to Earth. Jack Mustard, a senior author on the paper stated, “What’s even more important though is the return of the samples from Mars that are being collected right now by the Perseverance rover. When we get those back, we can actually check and see if this is right.”