Taking into consideration the ambitious plan to colonize Mars sometime in the future, it’s surprising how little we know about it and what it would actually be like to live on this planet. According to a new study, it appears that it snows there every night. So, is the red planet set on becoming a winter wonderland? Well, not exactly.
The rusty red soil is exposed to snow explosions known as “ice micro bursts” which only occur in the shadows, instead of the widespread snow cover on Earth. Picture something along the lines of snow ambushes rather than a snow idyll. Furthermore, this phenomenon occurs only under the condition that the clouds are quite low – around 1-2 kilometers (0.61-1.24 miles) above the surface. Otherwise, the snow particles will be destroyed before they get to the rusty soil. This is due to the fact that air pressure rises quickly as you go downwards, which also increases the local temperature and leads to evaporation-ready temperatures for the snow.
According to the authors of the study, it was believed that “snow precipitation occurs only by the slow sedimentation of individual particles”. But, this research has disproved this belief and demonstrated that the sudden snow explosion mechanism must have influenced the water cycle of Mars, past, and present.
Due to the incredibly thin atmosphere, Mars has a pretty low thermal insulation. During night time, on the surface, the mercury on Mars can drop to temperatures as low as -73°C (-100°F) on the equator and -125°C (-195°F) at the poles.
In order to figure out the effect of water ice clouds on Martian meteorology, study coauthor Aymeric Spiga, a planetary scientist at the French National Center for Scientific Research together with a team of researchers set up a high-resolution computer model. As such, their atmospheric models showed that these ice water clouds suddenly experience a rapid crystallization event.
Furthermore, thanks to the rapid and localized redistribution of heat, the air currents become strong and tempestuous and aim to push around the water ice crystals to radically fall out. Although some hit the surface, if it’s left to heat up too long as it’s falling, it turns into gas. These short-lived streaks of snowfall that don’t reach their destination are known as “virgas”.
Thus, the unstable and mercurial atmospheric conditions on Mars don’t allow regular snowfall. Since the Red Planet is also known as a world of extremes, only robots can experience for real. However, most of these robots actually can’t see these storms personally as snowstorms occur above them. According to Spiga, “snow precipitation has been spotted solely by the Mars Phoenix lander at night, using LIDAR laser sounding.”
These observations could become crucial ingredients in future complex global models used to understand Mars. Eventually, scientists would use these models to rewind time and look into the watery past of the planet. Several years ago they didn’t think water ice clouds affected Mars climate, but now they realized their big impact which made things richer and more complex than they suspected.
And by the way, Mars isn’t the only terrestrial planet that experiences snow because Io – Jupiter’s volcanic moon encounters a global sulfuric snow storm once it moves into the gas giant’s shadow.