Mars, or the “Red Planet,” has intrigued scientists for centuries with its reddish hue. Recently, a new study has attributed the red color to a mineral with a high iron content, which could tell us about the planet’s past. The research presents another piece of information regarding Mars’ environmental history, with the possibility that the planet was once inhabited. Let us explore the discovery of this study and how it may imply the ancient climate and habitability of Mars.
Scientists may have solved mystery of Mars’ red color
Mars’ surface is covered by iron oxide minerals in the dust. One of those minerals is ferrihydrite, an iron oxide, which is most responsible for reddening Mars, according to a new study. The red color of ferrihydrite, caused by the iron present in it, is considered to be among the primary reasons for Mars’s characteristic look. This specific iron oxide is significant as it precipitates under certain conditions, and this provides data regarding the past of water on the planet.
While ferrihydrite once was mentioned as a hypothesis for the red color of Mars, this research goes even further and presents more evidence. Postdoctoral fellow Adam Valantinas at Brown University is the lead author and states that this research utilizes very advanced laboratory methods and observational Mars mission data. Through making synthetic Martian dust in the lab and simulating the Martian environment, the researchers have learned better how ferrihydrite responds to light and other minerals.
An important aspect regarding the research is that ferrihydrite will form only under specific conditions in the environment—i.e., with the presence of cold water. The discovery refutes previous assumptions that the redness of Mars resulted from minerals such as hematite, which prefer much more arid conditions. Ferrihydrite demands lower temperatures and liquid water for survival. This discovery gives the promise that Mars in the distant past was possibly able to sustain a liquid water climate, which is what is needed if life is going to be there.
Understanding Mars’ climate change and the loss of liquid water
A much warmer and more humid Martian climate existed earlier—conditions under which liquid water and perhaps even life might be supported. However, over eons of billions of years, the planet revolutionized. As Mars’ atmosphere was stripped off by solar winds, possibly because the planet has a weak magnetic field, it cooled and dried. This climatic shift is one of the most important reasons Mars no longer has liquid water on its surface today. From a more watery, perhaps inhabited, to the barren, arid surface that we see today, this cycle of change has become an indispensable part of the history of the planet’s environment.
To validate their hypothesis, the scientists used data gathered through several space missions to Mars undertaken by NASA and the European Space Agency (ESA). These missions had given the scientists precious knowledge of the metal composition of the Martian surface, and it made it easy for them to investigate the existence and activity of ferrihydrite and other minerals. Through the comparison between observation data and laboratory experiments in test tubes, the team was able to mimic Martian conditions and learn more about how ferrihydrite could have been the reason behind Mars’s red appearance.
How NASA’s Perseverance rover is key to understanding Mars’ past?
NASA’s Perseverance rover plays a key part in verifying the findings of the study. Perseverance was launched in July 2020 and arrived on Mars in February 2021 and carries onboard high-tech scientific hardware to gather Martian rock and dirt samples. The samples will be proof of whether or not ferrihydrite exists on Mars and, if it does, whether the conditions that led to its formation ever actually existed there. Through examining these samples, scientists can determine if the hypothesis in this research is valid and where it places itself in the broader Mars environmental and geological record. This research offers new evidence that Mars’s red color is not merely a geological quirk but a diagnostic sign that reveals the history of the planet.
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