A solitary robot is currently exploring a meteor crater on Mars, collecting soil samples with its drill and robotic arm. NASA's Curiosity rover has been active on the Red Planet for nearly 12 years, continuing to make discoveries that challenge scientists' understanding of both Mars and Earth.
Recently, Curiosity identified sedimentary organic material with unusual properties, leaving researchers puzzled. The characteristics of these carbon-based materials, particularly their carbon isotope ratios, have surprised scientists. On Earth, such properties would typically indicate the presence of microorganisms, although they could also arise from non-biological chemical processes.
This finding on Mars has provided a crucial piece of evidence regarding the origins of life in the solar system. Co-author and chemistry professor Matthew Johnson noted that this discovery supports a decade-old theory regarding photolysis in the Martian atmosphere. Photolysis refers to the process where UV rays from the Sun supply energy to molecules, enabling chemical transformations. According to the research, approximately 20% of carbon dioxide molecules in the Martian atmosphere have been broken down into oxygen and carbon monoxide.
“Such complex carbon-based molecules are essential for life, the building blocks of life, one might say. This is akin to the age-old debate of which came first, the chicken or the egg. We demonstrate that the organic material found on Mars formed through atmospheric photochemical reactions, meaning life was not necessary for its creation. It remains to be seen whether this organic material contributed to the emergence of life on the Red Planet,” stated Professor Johnson from the University of Copenhagen's Department of Chemistry.
Moreover, since Earth, Mars, and Venus once possessed similar CO2-rich atmospheres, the implications of this photolysis could significantly enhance our understanding of how life began on Earth.