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If you have ever been in a desert area here on Earth, you have seen the tiny dust devils that seem to kick up out of no where. Dust devils on Mars are quite a bit more sinister than they are here. They are more like dust tornadoes, towering several kilometers in the air and hundreds of meters, if not a km, across.
During the Martian summer, the temperature can range from -90 C at night to 20 C during the day. The 110 degree difference facilitates the conditions necessary for the dust devils on Mars to form. The co-mingling of warm and cold air is the same basic condition needed for a tornado to form here on Earth. The main difference is that the atmospheric pressure on Mars is much lower, allowing the storms to develop more freely and grow larger.
Let’s take a look at what scientists think the conditions inside one of these storms would be like: As you walk across the surface a storm would form quickly, without much warning. Suddenly, you find yourself unable to see more than a few cm in front of you. The winds reach 30m/s in no time and are carrying huge amounts of iron oxide dust with them. You are terrified because that dust is like sandpaper and it is wearing away at your spacesuit, threatening to rip a hole in it at any moment. To make matters worse, the friction of the dust in the air creates electricity. Small discharges of static electricity play havoc with your suit and any device you might have to help you find shelter. Within minutes your are hopelessly lost and most likely dead from direct exposure to the Martian environment.
Now, imagine being trapped in the larger storms that can cover the entire planet.
Since there is no erosion on the Martian surface, rovers have been able to photograph lines on the surface that scientists attribute to past dust devils. Follow this link to see a NASA video that captured a dust devil on Mars.
The dust devils on Mars will be a major challenge that astronauts will face when they arrive on the planet. I say when, because human exploration of Mars has been a goal of NASA’s for decades. Challenges that seemed insurmountable 30 years ago are being eliminated and new ones tackled. Man may arrive in Martian orbit within the next 30 years. Wouldn’t that be something to see?
We’ve had several articles on Universe Today about dust devils on Mars. Here’s one where Spirit spotted a dust devil move across the Martian landscape. And another discussing how dust devils will be very difficult on astronauts.
Finally, if you’d like to learn more about Mars in general, we have done several podcast episodes about the Red Planet at Astronomy Cast. Episode 52: Mars, and Episode 91: The Search for Water on Mars.