Rime discovered on the highest volcanoes on Mars

A few hours before sunrise, a very thin – but extensive – layer of frozen water can be found on the tops of record-breaking volcanoes on Mars. Researchers came to this surprising conclusion after studying more than 30,000 photos of the red planet.

This can be read in the magazine Nature Geoscience. For the research, the scientists examined photos of the so-called Tharsis region, near the equator of Mars. This region is home to numerous gigantic volcanoes, including record-breaking tall ones like Olympus Mons. The latter volcano is as wide as France and, with a height of almost 22 kilometers, will not only go down as the highest volcano on Mars, but also as the highest volcano in our entire solar system!

And new research now reveals that the peaks of Olympus Mons and other volcanoes in the Tharsis region are sometimes covered by a very thin layer of water ice. And that is surprising, explains researcher Adomas Valantinas. “We did not consider it likely that frost could form near Mars’ equator, as daytime temperatures – due to incoming sunlight and the fact that Mars has a thin atmosphere – are relatively high both on the surface and on the tops of the mountains. ”

Temporary and thin
And yet frost has now been spotted on the high volcanoes. Or more precisely: in the bowl-shaped craters at the top of the volcanoes. The thin layer of ice is present only a few hours before sunrise; Once sunlight reaches the tops of the volcanoes, it evaporates. The ice layer is also super thin; only about as thick as a human hair.

The ice layer may be thin; it is quite extensive and therefore holds quite a lot of water. Estimated to be enough to fill 60 Olympic swimming pools, the researchers say. And during the colder seasons on Mars, that large amount of water can be found alternately in the atmosphere (in the form of water vapor) and on the surface (in the form of a layer of ice on the tops of the volcanoes).

The discovery
The discovery of the ice layer has a long lead-up. Researchers found first indications of its existence in high-resolution images taken by it Colour and Stereo Surface Imaging System on board ESAs Trace Gas Orbiter. To confirm the existence of the ice layer, observations from ESA’s Martian sorbiter were used, among other things. Mars Express. Ultimately, researchers analyzed more than 30,000 images to discover and confirm the existence of the ice layers.

The result is impressive, because it is the first time that frost has been discovered near the equator of Mars. The discovery naturally raises the question of how the thin ice layer can form here. The researchers do have ideas about that. They suspect that the unique way in which the air circulates above the high volcanoes creates a kind of microclimate in which frost can still form – against all expectations.

In the future, the scientists hope to gain more clarity about exactly how the thin ice layer is created. Ultimately, this should also provide a better picture of where exactly water can be found on Mars, how it moves and what processes are taking place in that thin, but still fairly complex atmosphere of Mars. Such information is of great value for future manned missions to Mars (which benefit from the presence of water on the red planet) and the search for Martian life (or traces thereof).