Mars’ reddish hue may be linked to a mineral called ferrihydrite, suggesting the planet had a habitable environment capable of sustaining liquid water in its ancient past, according to a new study.
A recent study has revealed that the distinctive red color of Mars is primarily due to a mineral known as ferrihydrite, which forms in the presence of cool water. This finding challenges previous assumptions that hematite was the main contributor to the planet’s iconic hue.
Ferrihydrite is unique in that it forms at lower temperatures than other minerals found on Mars, indicating that the planet may have once had conditions suitable for liquid water before transitioning to its current dry state billions of years ago. NASA highlighted this potential in a news release this week, noting that the agency partially funded the study.
The research, published in the journal Nature Communications, involved an analysis of data collected from various Mars missions, including those conducted by several rovers. The team compared this data to laboratory experiments designed to simulate Martian conditions, where they tested how light interacts with ferrihydrite particles and other minerals.
Adam Valantinas, the study’s lead author and a postdoctoral fellow at Brown University, explained the historical context of the research. “The fundamental question of why Mars is red has been considered for hundreds, if not thousands, of years,” he stated. Valantinas, who began this research as a Ph.D. student at the University of Bern in Switzerland, emphasized the significance of their findings. “From our analysis, we believe ferrihydrite is present in the dust and likely in the rock formations as well,” he added.
While ferrihydrite’s role in Mars’ coloration has been suggested before, this study provides a more robust framework for testing the hypothesis using both observational data and innovative laboratory techniques that replicate Martian dust.
Jack Mustard, the senior author of the study and a professor at Brown University, described the research as a “door-opening opportunity.” He noted the importance of the ongoing sample collection by the Perseverance rover, stating, “When we get those back, we can actually check and see if this is right.” Mustard’s comments underline the potential for future discoveries regarding Mars’ geological history.
The study suggests that Mars may have once had a cool, wet climate that could have supported life. Although the planet’s current atmosphere is too cold to sustain life, evidence indicates that it once had an abundance of water, as reflected in the presence of ferrihydrite in its dust.
Geronimo Villanueva, Associate Director for Strategic Science at NASA’s Goddard Space Flight Center and a co-author of the study, remarked on the implications of the findings. “These new discoveries point to a potentially habitable past for Mars and highlight the value of coordinated research between NASA and its international partners when exploring fundamental questions about our solar system and the future of space exploration,” he said.
Valantinas further elaborated on the research objectives, stating, “What we want to understand is the ancient Martian climate and the chemical processes on Mars—not only ancient but also present.” He also addressed the habitability question, asking, “Was there ever life?” To answer this, researchers need to understand the conditions that existed during the formation of ferrihydrite.
According to Valantinas, the formation of ferrihydrite requires specific conditions where oxygen from the atmosphere or other sources interacts with iron in the presence of water. These conditions were markedly different from today’s dry and cold environment. As Martian winds spread the dust across the planet, they contributed to Mars’ iconic red appearance.
As research continues, the findings from this study may reshape our understanding of Mars’ geological history and its potential to have supported life in the past, paving the way for future exploration and discovery.
According to NASA, the implications of this research extend beyond just understanding Mars’ color; they may also provide insights into the planet’s capacity to host life in its ancient past.