BERN / MÜNCHEN (November 25, 2024) - A recent discovery of water frost on the peaks of Mars' Tharsis volcanoes has sparked excitement within the scientific community. These volcanoes, including Olympus Mons, the tallest mountain in the solar system at 26 kilometers, are situated at low latitudes near the Martian equator. The formation of frost in these regions, typically characterized by intense sunlight, was unexpected.
This finding was made possible by the ExoMars program of the European Space Agency (ESA), which has been exploring Mars since 2018 using the Trace Gas Orbiter (TGO). The orbiter is equipped with the Color and Stereo Surface Imaging System (CaSSIS), developed by an international team led by Professor Nicolas Thomas from the University of Bern. CaSSIS provides high-resolution color images of the Martian surface, enabling a team led by Dr. Adomas Valantinas to detect the frost.
Valantinas, who was a PhD candidate at the University of Bern until October 2023 and is now a visiting researcher at Brown University, noted that the thin Martian atmosphere inadequately cools surface temperatures. However, ascending winds transport moisture-laden air from the lowlands, leading to condensation and frost formation.
The discovery has been validated through independent observations from the high-resolution stereo camera (HRSC) aboard the ESA's Mars Express orbiter and the Nadir and Occultation for Mars Discovery (NOMAD) spectrometer on the TGO. These instruments demonstrate the value of combining various orbital measurement tools to enhance the understanding of interactions between the Martian atmosphere and surface.
Although frost deposits are only briefly visible around sunrise before evaporating in sunlight, they cover a significant area. The amount of frost corresponds to approximately 150,000 tons of water exchanged daily between the surface and atmosphere during the cold season, equivalent to the volume of about 60 Olympic swimming pools.
The results of this study, published in the journal Nature Geoscience, emphasize the importance of long-term observation of planetary processes. They provide valuable insights into the Martian water cycle, crucial for future exploration of the planet. Understanding where water can be found on Mars and how it moves may not only shed light on the planet's habitability but also provide essential resources for future Mars missions.