In March, I wrote about a dust devil on Mars spotted by the Mars Reconnaissance Orbiter. It was 800 meters high, which I said was "huge."
Yeah. A week later, MRO spotted another dust devil ... that was 20 kilometers high!
[Click to vortexenate.]
Dust devils form when air blows over warmer air rising off of the plains. If conditions are right, a vortex forms, becomes vertical, and you get a dust devil. It happens all the time on both Earth and Mars, and is common in the spring. It's spring in the Martian northern hemisphere now, so there you go.
The folks at MRO put together a cool video to show what this monster would have looked like from the ground, and how it moved. Mind you, this is based on the image: Shadows and sun angle give the height, and the shape of the shadow tells you the shape of the funnel. [You may have to refresh the page if you don't see the video directly below.]
What a sight! I've seen dozens of dust devils, including some that were clearly hundreds of meters high, and they're mesmerizing and eerie. This picture is a reminder that as different as Mars is from Earth, there are also some striking similarities. And that just because Mars is smaller and has a thinner atmosphere, not everything it does is on a smaller scale than here.