Why does Mars have a dusty atmosphere?
The Martian atmosphere is rather thin, but fine (dust) particles still remain in suspension for a very long time, not to mention the famous Martian dust storms. So, how come dust particles do not settle faster on Mars? It is true that similarly sized dust will settle from the thinner Martian atmosphere sooner than it would on Earth. For example, the dust suspended by the 2001 global dust storms on Mars only remained in the Martian atmosphere for 0.6 years, while the dust from Mt. Pinatubo took about 2 years to settle. However, we shouldnt forget that even the 2001 global dust storms on Mars moved only the equivalent of a very thin dust layer about 3m thick if deposited with uniform thickness between 58 degrees N and S of the equator. The difference in the concentration of dust in Earth’s atmosphere and that of Mars stems from a key factor: On Earth, dust that leaves atmospheric suspension usually gets aggregated into larger particles through the action of soil moisture or gets suspende
