Forget everything you think you know about Mars. In a study published in Nature Geoscience, scientists confirm that there is snow on the Red Planet. It’s not what you might think, however. Mars experiences explosions of snow known as “ice microbursts” that only occur in the shadows and are very unlike snowfall on Earth. This finding is challenging previous notions about the planet’s history and the likelihood of future generations colonizing it.
On Mars, the clouds have to be very low to the surface (about 1 to 2 kilometers, or 0.61 to 1.24 miles), or else the snow will be annihilated before it even reaches the rusty soil. This is because the air pressure increases rapidly as it descends downwards. In turn, the local temperature is increased and snow reaches evaporation-ready temperatures.
As IFLScience reports, scientists previously believed snow precipitation occurred only by “the slow sedimentation of individual particles.” The authors now know this isn’t the case. Their research shows that the sudden snow explosion mechanisms must have affected “Mars’ water cycle, past and present.”
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Because the red planet’s atmosphere is incredibly thin, its thermal insulation is pretty low. At night, the mercury can drop as low as -73°C (-100°F) on the equator surface, and -125°C (-195°F) at the poles. When sunlight glances Mars, water at the equator is given just enough energy to evaporate. This results in the formation of low-pressure clouds — a phenomenon NASA is already tracking.
Because the temperature of the Red Planet drops considerably at night, the rapid and localized redistribution of heat results in air currents becoming unstable. Water ice crystals then fall out in rapid succession. Some crystals may reach the surface, but others sublimate into a gas. The streaks of snowfall that fail to reach the surface are known as “virgas.”
For now, only robots are able to experience Mars’ unique snowfall. But if humans ever do colonize Mars — a feat Elon Musk and Stephen Hawking are ambitious to see accomplished in their lifetimes, maybe we’ll get to experience the planet’s unique weather patterns firsthand.