James Wray, assistant professor in the School of Earth and Atmospheric Sciences, is an expert on Mars. He comments on NASA's latest image of the Red Planet, which shows a giant dust devil that stretches nearly 12 miles above the surface.
Geologically, much of the action on Mars ended a few billion years ago. The largest volcanic eruptions, meteoroid impacts and liquid water flows all fizzled out long ago. But the winds on Mars continue to blow and, even though the Martian atmosphere is over 100 times thinner than Earth's, these winds can still lift dust particles high into the air.
This image captures one of the largest dust devils ever recorded. Its long shadow cast upon the Martian surface suggests that it stretches approximately 12 miles up into the Martian atmosphere, much higher than commercial airplanes fly! This is comparable to large tornadoes on Earth and would be a stunning sight to behold for any future astronauts standing on this region of Mars.
This new image is yet another example of "giant-sized geology" on Mars. Mars has the largest volcano in the solar system (several times the height of Mt. Everest), a canyon almost as wide as the United States and possibly the largest impact crater in the solar system, spanning its entire northern hemisphere. Now we know that Mars can build dust devils approximately 100 times their maximum height on Earth because of its much thinner atmosphere.
It's yet another example of how we can better understand Earth processes by seeing how they differ on other worlds, where the physical parameters (gravity, atmospheric density and composition) are very different.
To see a video of the simulated dust devil, courtesy of NASA/JPL-Caltech, click here.
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