Scientists Make a Big Breakthrough on How Mars Got Its Red Color, Findings Indicate It Had Life-Forming Elements

Mars's red color has always fascinated aficionados. The planet was named after a Roman god because people thought a blood-stained hue surrounded it, stated Live Science. For decades, experts believed the red color was due to the planet's arid condition, but new research has proven otherwise. These findings have been discussed in a study published in Nature Communications. 

Past studies have confirmed that the red of Mars is a consequence of rusted iron minerals. These minerals have possibly been spread across the planet's dust for billions of years through winds. Researchers used to think that this rust was facilitated in dry conditions. The new study, however, claims that the red found in Mars's environment was similar to ferrihydrite. The mineral is a form of iron oxide that carries water. This implies that the element interacted with the planet's environment when it had water.

The study found its results after examining data garnered from three spacecraft orbiting Mars — the European Space Agency's (ESA) Mars Express orbiter and Trace Gas Orbiter (TGO) and NASA's Mars Reconnaissance Orbiter and three NASA rovers. From the data, the researchers got a good idea regarding the composition of minerals and the size of dust particles inside the planet.

Thereafter, researchers utilized an advanced grinder machine and created a replica of dust they observed in the Mars environment. The analysis of the dust particles indicated to the team that it had similar features to ferrihydrite. "We found that ferrihydrite mixed with basalt, a volcanic rock, best fits the minerals seen by spacecraft at Mars," said Valantinas, stated CNN. "The major implication is that because ferrihydrite could only have formed when water was still present on the surface, Mars rusted earlier than we previously thought. Moreover, the ferrihydrite remains stable under present-day conditions on Mars."

Researchers have yet to figure out how ferrihydrite originated on the Red Planet. "Our findings have opened up new questions about the Martian past," first author Adomas Valantinas, a planetary scientist at Brown University, shared, Live Science stated. "We still don't know the original source location of the ferrihydrite before it was distributed globally through dust storms, the exact chemical composition of Mars' atmosphere when the ferrihydrite formed, or the precise timing of Mars' oxidation."

The results illuminated the experts regarding past conditions on Mars and challenged several past assertions, stated CNN. "Since this water-containing rust blankets most of the Martian surface, it suggests that liquid water in Mars’ ancient past may have been more widespread than previously thought," Valantinas said. "This suggests that Mars once had an environment where liquid water was present, which is an essential prerequisite for life. Our study reveals that ferrihydrite formation on Mars required the presence of both oxygen — whether from the atmosphere or other sources — and water capable of reacting with iron."

The findings further assert that the environment on Mars did not directly turn from moist to dry. There were several other conditions in play. "Ferrihydrite requires liquid water and forms rapidly under cold, wet, oxidizing conditions, typically at circumneutral pH. Hematite, in contrast, can form in warm and dry conditions through slow chemical weathering processes," Valantinas said, stated Live Science. "The finding suggests Mars experienced periods of aqueous alteration — cold, wet conditions with active chemistry — before transitioning to its current desert state. This provides new constraints on the timeline of Mars's habitability and indicates potential environments where microbial life could have thrived."

Researchers want to examine the samples brought by ESA's Rosalind Franklin rover and the NASA-ESA Mars to further understand the planet's history. "Some of the samples already collected by NASA's Perseverance rover and awaiting return to Earth include dust,"  Colin Wilson, project scientist for ESA's TGO and Mars Express, added. "Once we get these precious samples into the lab, we'll be able to measure exactly how much ferrihydrite the dust contains, and what this means for our understanding of the history of water — and the possibility for life — on Mars."