A new study may have revealed the true source behind how the Red Planet got its hue.
It’s been long thought that Mars shines red due to the rusted iron minerals within the dust that covers the planet — but a study published Tuesday in the journal Nature Communications suggests otherwise.
“The fundamental question of why Mars is red has been considered for hundreds if not for thousands of years,” lead author Adam Valantinas, a postdoctoral fellow at Brown University who started the work as a Ph.D. student at the University of Bern, Switzerland, said.
Because of its close proximity to Earth, Mars is one of the most well-studied planets in the solar system
But now, the “understanding of why Mars is red has been transformed,” Valantinas said.
The research combined spacecraft data from the European Space Agency (ESA) and National Aeronautics and Space Administration (NASA) with advanced laboratory experiments.
Findings suggested that the Red Planet got its color from ferrihydrite, a form of iron oxide that needs water to form, rather than hematite — which is what’s been long thought as the reason behind the red hue.
“We were trying to create a replica martian dust in the laboratory using different types of iron oxide. We found that ferrihydrite mixed with basalt, a volcanic rock, best fits the minerals seen by spacecraft at Mars,” Valantinas explained.
By recreating the dust, scientists were able to compare the properties of the synthetic dust to the samples from Mars.
The conclusion suggests that Mars may have rusted earlier in history than previously thought, during a time when water was still present on the surface. Because ferrihydrite forms rapidly in cool water, its presence would have formed on wetter land.
The presence of ferrihydrite implies that rather than the dry land we think of when we think of Mars, the planet had a period of cold and wet conditions.
Previous research did not detect water in the planet’s iron oxides, leading researchers to believe that the red dust formed in dry conditions, therefore it was likely due to hematite.
“Mars is still the Red Planet. It’s just that our understanding of why Mars is red has been transformed,” Valantinas added.
Future missions and tests can further solidify the findings and deepen our understanding of the history of Mars.
Samples have been collected NASA’s Perseverance rover and when it returns to Earth, they will be examined to see exactly how much ferrihydrite it contains.
