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| NASA/JPL/University of Arizona |
The full image was taken on February 16th, 2012, at a time of the Martian year when it's near its aphelion, or farthest point from the Sun. Earth reaches its aphelion in the beginning of July.
Whirlwinds seem to be fairly common on Mars, with quite a few photos having been taken from various science instruments. The rover Spirit was able to capture multiple images in sequence on a number of occasions (.gifs enclosed).
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| Dust devil on Mars, captured by Spirit rover in 2005. |
As on Earth, these miniature tornadoes form when sunlight warms the ground, creating a slight updraft that can, with the help of an easy breeze, mix with the cooler air above it to form a swirling column of air and dust.
Given that they are thought to be largely dependent on heat from the Sun (to power winds), researchers were reportedly surprised to see such regular activity at Mars' aphelion.
This is more evidence that Mars has many surprises left for us. It will be a great day when humans become truly interplanetary and explore our little red brother. I have hope that it will happen within my lifetime because are seeing a new generation of super-wealthy entrepreneurs that grew up on science fiction. I'm looking at you, Elon Musk and Richard Branson.
