(ORDO NEWS) — Researchers from Washington University in St. Louis (USA) have destroyed all hopes of scientists that atmospheric oxygen once existed on Mars.
Just because NASA rovers detected manganese oxides on Mars in 2014 does not mean that oxygen was actually present in the planet’s atmosphere.
Scientists have found that under Martian-like conditions, manganese oxides can easily form without any presence of atmospheric oxygen.
However, the fact that the material was formed without oxygen does not mean that there were no oxygen molecules in the atmosphere.
Using simulations, scientists concluded that manganese oxidation would not have been possible in the carbon dioxide-rich atmosphere present on ancient Mars.
“The relationship between manganese oxides and oxygen suffers from a number of fundamental geochemical problems,” said study author Professor Jeffrey Catalano.
Kaushik Mitra, a PhD researcher from Stony Brook University, participated in the study with Catalano.
The study showed that Mars is saturated with halogen elements such as chlorine and bromine.
“Halogens occur on Mars in non-Earth forms and in much greater abundance, and we hypothesized that they would be important to the fate of manganese,” Catalano said.
So Catalano and his colleagues conducted laboratory experiments using chlorate and bromate to oxidize manganese in water samples that mimicked the liquids that were present on the surface of Mars in the ancient past.
The researchers found that the production of manganese oxide does not require the presence of oxygen and that total oxygen is completely incapable of forming these elements.
“Oxidation doesn’t require oxygen by definition,” Mitra said.
“We have previously proposed viable oxidizers on Mars other than oxygen or via ultraviolet photo-oxidation, which help explain why the Red Planet is red.
In the case of manganese, we simply did not have a viable alternative to oxygen that could explain manganese oxides so far.”
However, scientists emphasized that just because there was no atmospheric oxygen in the past does not mean that there was no life on the Red Planet.
“Even on Earth, there are a few life forms that don’t require oxygen to survive,” Mitra said.
“I don’t think of it as a ‘barrier’ to habitability – just that there probably weren’t oxygen-based life forms.”
Many organisms can survive in halogen-rich environments like those found on ancient Mars.
“We need more experiments done in different geochemical settings that are more suited to specific planets like Mars, Venus and ocean worlds like Europa and Enceladus in order to have a correct and complete understanding of the geochemical and geological environment on these planetary objects,” Mitra said.
“Each planet is unique in itself, and we cannot extrapolate observations made on one planet to accurately understand another planet.”
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