From the August 2011 issue

How is it possible that Mars can have dust devils and global dust storms with such a thin atmosphere?

Jon Wallen, Renton, Washington
By | Published: August 29, 2011 | Last updated on May 18, 2023
A dust devil moves across Gusev Crater on the Red Planet. Faster wind speeds on Mars help keep the dust suspended in the thin martian atmosphere. NASA/JPL/Texas A&M

Mars requires a wind speed about 10 times faster than on Earth to lift dust. Once the dust is off the surface, it needs to remain suspended in the air to form a cloud. Because Mars is less massive and thus has a lower surface gravity than Earth, dust falls to the surface more slowly.