Scientists have unravelled the mystery behind Mars’ missing atmosphere, shedding light on the fate of the planet’s once-thick air that could have sustained life. According to a study by researchers at the Massachusetts Institute of Technology (MIT), Mars’ atmosphere might have been absorbed by the planet’s iron-rich clay billions of years ago.
When Mars lost its atmosphere, it transitioned from a potentially habitable world to a cold desert. The disappearance of the Martian atmosphere has intrigued scientists for years, but now, the answer could be ‘hiding in plain sight,’ within the planet’s crust, the researchers suggest.
The MIT team believes that a significant portion of Mars’ missing atmosphere was converted into methane and incorporated into the planet’s clay surface around 3.5 billion years ago. This finding holds promise for potential future missions between Mars and Earth, as the methane stored in Martian clay could potentially be utilised as a fuel source.
Dr Oliver Jagoutz, a professor at MIT’s Department of Earth, Atmospheric and Planetary Sciences, expressed optimism about the possibility of using the methane on Mars in the future, stating, “This methane could still be present and maybe even used as an energy source on Mars in the future.”
The research indicates that Mars was once equipped with the necessary conditions for life to flourish, including a thick atmosphere, liquid water, and a strong magnetic field. Scientists theorise that over billions of years, the interaction between rocks on Mars and water containing carbon dioxide led to the storage of carbon in the clay surface, in the form of methane, explaining the disappearance of CO2 from the planet’s early atmosphere.
The process involved water trickling down through rocks on the Martian surface, initiating a slow chemical reaction that extracted carbon dioxide from the atmosphere and converted it into methane. This transformation was facilitated by minerals rich in iron, such as olivine, which are abundant on Mars.
Dr Joshua Murray, a recent graduate from MIT’s EAPS, emphasised the prevalence of CO2 on Mars during that era, with carbon dioxide present in various locations and water saturated with CO2. The subsequent reactions led to the creation of methane, with hydrogen from water combining with carbon dioxide to form the fuel source.
The researchers estimated that the smectite clays on Mars could potentially hold up to 1.7 bar of carbon dioxide, accounting for approximately 80% of the early Martian atmosphere. This suggests that the missing atmosphere of Mars could have been sequestered within the clay-rich crust of the planet, providing a plausible explanation for its absence.
The findings, published in the journal Science Advances, offer a compelling insight into the fate of Mars’ atmosphere and the potential for utilising methane as a valuable resource on the red planet. The researchers’ innovative approach highlights how Mars’ missing atmosphere may have been hidden in plain sight within its geological makeup, offering new avenues for exploration and understanding of the planet’s evolution.