Formaldehyde Deposition on Mars and the Search for Life

About 3.8 to 3.6 billion years ago, Mars was a warm and wet planet, with favorable conditions for the formation of formaldehyde (H2CO) in its atmosphere. This compound is an important precursor for the formation of organic molecules, such as sugars and amino acids, which are essential for life as we know it ². Researchers from the Institute of Science Tokyo, Tohoku University, and University of Washington developed a model to understand how formaldehyde deposited on the Martian surface. They discovered that the distribution of this compound was strongly correlated with the presence of water vapor in the atmosphere ¹.

Mars Atmospheric Modeling

The scientists used a photocomputational model coupled with a global climate model to simulate the atmospheric conditions of Mars during the late Noachian and early Hesperian periods. They considered an atmosphere with 2 bar of CO2 and 6% of H2, with an obliquity of 40°. The extreme ultraviolet radiation from the Sun, which was about 10 times stronger at that time, played a crucial role in the production of formaldehyde ².

The results indicate that formaldehyde deposition was higher in wet regions and around large bodies of water, such as the northern ocean of Mars. Additionally, areas with elevated topography, such as the Tharsis and Elysium Montes, also showed high deposition due to orographic precipitation ¹.

These findings suggest that basins adjacent to persistently wet regions could have accumulated formaldehyde and promoted the synthesis of organic matter. These areas are, therefore, potential landing sites for future missions seeking to investigate the ancient chemical evolution of Mars and the possibility of the origin of life ¹.