Early settlers on the red planet might get a white Christmas after all. Because we now know that it actually snows on Mars.
You might be surprised to consider this news, especially if you’ve seen pictures of Mars that seem to show snow-covered ice caps at the poles of the planet. But don’t be deceived – you can’t just melt that ice and drink it because it’s actually composed of frozen carbon dioxide, not water.
But it now seems that there are in fact flash snow storms on Mars made up of regular old H2O, which is some important information for scientists who are trying to figure out how the water cycle works on the planet which is still our best bet for space colonization within Earth’s immediate neighbourhood.
These aren’t the type of snowstorms that (non-Australian) Earthlings are accustomed to, however. They are brief micro bursts of snowfall that seem to only occur in the shadows.
Here’s how it works: in the hotter regions near the equator of Mars, there’s enough heat from the sun to drive the evaporation of water, which leads to atmospheric clouds of water vapour. And when these clouds are cooled by the absence of sunlight at a later time, they can very quickly crystallize into snow and fall from the sky.
So why haven’t our various Mars probes picked up on this until now? It turns out they actually might have been present for snow microbursts without us even noticing, as in many cases the microbursts melt before they are even able to hit the ground. So there could well have been snowstorms directly above one of the probes without us being aware of it.
Thanks to the ephemeral nature of Martian snowstorms, it looks as though future colonists dreaming of skiing fresh powder on the slopes of Olympus Mons — the Solar System’s tallest mountain — might want to bring their own snow machines.
Come to think of it though, the fact that we are just finding out now about snow on Mars underscores how much we still have to learn about our prospective future colony. On the one hand, it’s amazing that we know as much as we do; on the other hand, if we’re only just finding out these sorts of basic facts right now, we clearly have a lot to learn about the place before we can start living there.