Ned Stark’s infamous meme strikes again, but this time it’s not about Earth or even a fictional universe on Earth. Mars is basking in summer right now, but remember what Stark said (before losing his mind): “Winter is coming.”
Most Martian snow is actually the same frozen carbon dioxide that we recognize as dry ice. While there is also water ice on the Red Planet, there is so much CO2 in its solid state that it makes up most of the polar ice caps, and up to 7 feet of snow made up of the same substance can be expected every winter. Winter on Mars can actually tell us more about how the planet experiences seasonal changes, such as the growth of its ice caps when it becomes a freezer and its retreat later.
So what can the Martian ice caps reveal about what happens to the planet during a deep freeze and throughout the summer? An international team of researchers, led by Haifeng Xiao from the Institute of Geodesy and Geoinformation at the Technical University of Berlin, recently published a study on its unusual snow and ice using the arXiv preprint server.
“For snow to form from clouds, carbon dioxide needs something to condense – for example, a small particle of silicate or dust,” Xiao told SYFY WIRE. “During the sublimation phase of the seasonal polar caps in spring, atmospheric warming associated with dust storm activity can accelerate the thinning process.”
To get an idea of the amount of CO2 snow and ice found on Mars at different times of the year – remember that a Martian orbit and therefore a year is twice that of Earth – Xiao a used data from the Mars Orbiter laser altimeter (MOLA) aboard the Mars Global Surveyor (MGS). MOLA measures the height of ice caps, as well as their volume, to determine the amount of ice that accumulates and sublimates (goes directly from a solid to a vapor). Incorporating this data into a digital terrain model (DEM) gave the team a measure of the average snow surface.
There are other weather phenomena that can influence snowfall and CO2 vaporization on Mars. Dust in Martian snowfall lowers albedo, or the ability to reflect sunlight, and just like Winterfell, there is more snow left in the north in spring and summer because there are more particles of dust for this snow to form. As a result, sunlight bounces off the snow and ice on the surface and returns to space. While other studies had resulted in measurement errors, Xiao found that using both MOLA data and a DTM resulted in greater accuracy.
“To overcome the previous issues, we used the height corrections from the co-recording of underlying DTM-specific MOLA profile segments as a new approach, and a new post-correction procedure was also used for this. end, ”he said.
Unsurprisingly, the deepest snow and ice can be expected at the poles, especially the south pole; the poles are the most sensitive to climate change. Sublimation leads to strange formations like araneiform spiders. Xiao’s team will use their combined MOLA and DTM approach to study the polar regions in more detail while continuing to research how polar ice caps and CO2 snow and ice in general continue to evolve on Mars. Their research could serve as a basis to report any suspicious element during future observations with even more powerful instruments.
Over the course of a year on Mars, or 687 Earth days, atmospheric pressure will drop, as the accumulation of snow and ice removes about 30% of what is left of the planet’s almost non-existent atmosphere. The long-dead Viking landers actually helped prove it. The pressure in the atmosphere will rise and fall throughout the year in the final resting places of landers, and these fluctuations are consistent with the growth and shrinkage of ice caps.
Xiao’s colleague, planetologist Jingyan Hao, believes the cycle of condensation and sublimation could tell us more about the evolution of the Martian climate.
“If we can better understand how features such as araneiforms form and change, with seasonal polar ice caps varying under changing conditions, we will better understand the past and present climates and environments of Mars and how they evolved,” says -she.
Don’t expect Perseverance to start building a snowman anytime soon.