The redness of Mars has made the planet one of the most recognizable in the solar system with its hue serving as a topic of debate in planetary science. A recent study by Brown researchers found the red color is due to ferrihydrite, a mineral in Mars’s dust, raising questions about previous life on Mars.
The study, which was led by Adomas Valantinas — a postdoctoral fellow in the Department of Earth, Environmental and Planetary Sciences — and John Mustard, a professor in DEEPS, used X-ray diffraction to confirm the ferrihydrate’s structure.
While many planetary scientists thought that ferrihydrite should crystallize on Mars’s surface, the researchers found that “ferrihydrite is thermodynamically stable and does not crystallize in Martian conditions,” according to Valantinas.
The persistence of ferrihydrite may suggest that Mars’s environment previously contained liquid water, presenting larger questions about life outside of Earth.
“One of the biggest questions that I was interested in … was (life) beyond Earth,” Valantinas said. To gauge the future potential for life on Mars, “we need to understand the conditions and the conditions that were present in the ancient Martian past.”
Through rock formation analysis, the researchers hope to continue their studies to understand when Mars turned red.
In this study, Valantinas used reflective spectroscopy, remote sensing observation and spectrometers from Mars’s orbit and rover data to reinforce his findings.
Inspired by the work of other scientists in the field, Valantinas started to explore this topic during the final year of his PhD.
“I was reading a lot of literature about what has been done in the past and what the community knows about the dust properties” of Mars, Valantinas said. “Not only physical properties, but also mineral composition.”
After completing his PhD at the University of Bern, Valantinas continued the research with Mustard at Brown.
“We did some additional measurements at the University of Grenoble in France with a few French colleagues, and then we even sent a few samples to the University of Winnipeg in Canada,” he said.
Mahmoud Hallak ’25, who is concentrating in physics on the astrophysics track, described the prominence of Mars’ color in astronomy.
“If you were to observe it with the naked eye and through a telescope, you can separate Mars from the other stars in the night skies,” Hallak said. “Mars is just a deep, deep orange that you can’t miss.”
Mustard expressed concern for the future of research funding in the field, citing uncertainties with funding in the current political climate.
“I’ve always felt that science was a bipartisan issue,” Mustard said, noting that he has noticed a shift in attitude against scientific research.
“There is a perception in parts of the ongoing administration that science should not be trusted,” he added. “That is really hard to hear as … the depth of our discussions and debates that go into our findings are really important.”
