Under Mars-like conditions, manganese oxides can be formed without oxygen: Scientists | Tech News

Under Mars-like conditions, manganese oxides can be formed without oxygen: Scientists

When NASA's Mars rovers found manganese oxides on Mars in 2014, the discovery sparked some scientists to suggest that the red planet might have once had more oxygen.

By:ANI
| Updated on: Dec 27 2022, 22:51 IST
Top NASA tech that solved Mars myths and mysteries like never before
NASA's Mars rovers
1/10 Humans have been studying Mars for hundred of years. In 1609, Galileo was the first person to peer through a telescope and get a more intimate image of what many could only have dreamed of. (Pixabay)
NASA's Mars rovers
2/10 An up close and personal view of the red planet emerged as time progressed and so did the capabilities of telescopes. In fact, from the late 1800s to the mid 1900s, many astronomers believed that Mars was home to majestic seas and lush areas of vegetation. The Dark markings on Mars surface were once believed to be caused by vegetation growing and dying. (Pixabay)
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3/10 Some even believed that intelligent life existed on Mars just because of what they saw through their simple telescopes. But that is exactly was science is about-you make educated guesses based on what you know, then change your ideas based on what you learn. (NASA)
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4/10 Now, thanks to new sophisticated equipment and robotic visits to Mars, it turns out they were caused by Martian wind. It was not until the 1960s, when NASA's Mariner missions flew by and snapped pictures of Mars that many of the myths about the red planet were dispelled. (NASA)
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5/10 That does not make Mars any less interesting. The possibility that life actually existed once on Mars is still a distinct possibility. Or it may even be existing on Mars today! No, not in the form of little green men, but on a microbial level. (NASA)
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6/10 Now, taking pictures is great and all. But nothing is better than getting to know the real thing. So, to get a better feel of Mars, Scientists and engineers built some nifty technologies, from spacecrafts to reach Mars and rovers (vehicles) to actually trundle and explore the planet. (NASA/JPL)
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7/10 Among the earliest tech deployed for Mars was Phoenix. It was launched on August 4, 2007 and so began its 9-month long, 681 Million km journey to the legendary red planet. Now, landing on a planet is not as easy as simply dropping a spacecraft onto it. There is actually a lot of steps to the process. (NASA)
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8/10 On May 25, 2008, Phoenix entered Mars atmosphere. It used its heat shield to slow down the high speed entry of 5600 meters per second or around 12500 miles per hour. It released a supersonic PARACHUTE, then detached from its parachute and used its rocket engines to land safely on the planet's surface. Phoenix' landing spot was further north and closer to the ice covered poles than any spacecraft has ever been before. (NASA)
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9/10 Phoenix had two primary goals: One was to study the history of water in the Martian arctic and the other was to search for evidence of a habitual zone and assess the biological potential of the ice soil boundary. And to do that the spacecraft was packed full of gizmos and gadgets to perform all sets of experiments and tests. One of these gizmos was a robotic arm with a shovel attached. It was used to dig up samples of the martian soil for experiments! (NASA)
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10/10 Another top tech on the Mars surface was the Surface Stereo Imager, which is really just a fancy name for the camera. Three surface stereo imagers were Phoenix' eye. Engineers built the device with two optical lenses that would allow for a three dimensional view, just like our eyes. And the SSI sent back some amazing images of the martian landscape. (Source: NASA/Justin Tully) (NASA)
NASA's Mars rovers
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NASA's Mars rovers found manganese oxides in Gale's rocks. (NASA)

When NASA's Mars rovers found manganese oxides in rocks in the Gale and Endeavor craters on Mars in 2014, the discovery led some scientists to suggest that the red planet might have once had more oxygen in its atmosphere billions of years ago.

The minerals probably required abundant water and strongly oxidizing conditions to form, the scientists said. Using lessons learned from Earth's geologic record, scientists concluded that the presence of manganese oxides indicated that Mars had experienced periodic increases in atmospheric oxygen in its past -- before declining to today's low levels.

But a new experimental study from Washington University in St. Louis upends this view.

Scientists discovered that under Mars-like conditions, manganese oxides can be readily formed without atmospheric oxygen. Using kinetic modeling, the scientists also showed that manganese oxidation is not possible in the carbon dioxide-rich atmosphere expected on ancient Mars.

"The link between manganese oxides and oxygen suffers from an array of fundamental geochemical problems," said Jeffrey Catalano, a professor of earth and planetary sciences in Arts & Sciences and corresponding author of the study published Dec. 22 in Nature Geoscience. Catalano is a faculty fellow of the McDonnell Center for the Space Sciences.

The first author of the study is Kaushik Mitra, now a postdoctoral research associate at Stony Brook University, who completed this work as part of his graduate research at Washington University.

Mars is a planet rich in the halogen elements chlorine and bromine compared to Earth. "Halogens occur on Mars in forms different from on the Earth, and in much larger amounts, and we guessed that they would be important to the fate of manganese," Catalano said.

Catalano and Mitra conducted laboratory experiments using chlorate and bromate -- dominant forms of these elements on Mars -- to oxidize manganese in water samples that they made to replicate fluids on the Mars surface in the ancient past.

"We were inspired by reactions seen during chlorination of drinking water," Catalano said. "Understanding other planets sometimes requires us to apply knowledge gained from seemingly unrelated fields of science and engineering."

The scientists found that halogens converted manganese dissolved in water into manganese oxide minerals thousands to millions of times faster than by oxygen. Further, under the weakly acidic conditions that scientists believe were found on the surface of early Mars, bromate produces manganese oxide minerals more quickly than any other available oxidant. Under many of these conditions, oxygen is altogether incapable of forming manganese oxides.

"Oxidation does not necessitate the involvement of oxygen by definition," Mitra said. "Earlier, we proposed viable oxidants on Mars, other than oxygen or via UV photooxidation, that help explain why the red planet is red. In the case of manganese, we just did not have a viable alternative to oxygen that could explain manganese oxides until now."

The new results alter foundational interpretations of the habitability of early Mars, which is an important driver of ongoing research by NASA and the European Space Agency.

But just because there was likely no atmospheric oxygen in the past, there's no particular reason to believe that there was no life, the scientists said.

"There are several life forms even on Earth that do not require oxygen to survive," Mitra said. "I don't think of it as a 'setback' to habitability -- only that there was probably no oxygen-based lifeforms."

Extremophile organisms that can survive in a halogen-rich environment -- like the salt-loving single-celled organisms and bacteria that thrive in the Great Salt Lake and the Dead Sea on Earth -- might also do well on Mars.

"We need more experiments conducted in diverse geochemical conditions that are more relevant to specific planets like Mars, Venus, and 'ocean worlds' like Europa and Enceladus in order to have the correct and full understanding of the geochemical and geological environments on these planetary bodies," Mitra said. "Every planet is unique in its own right, and we cannot extrapolate the observations made on one planet to exactly understand a different planet."

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First Published Date: 27 Dec, 01:35 IST
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