Eli5: Why does dust only form thin layers?


You never see a big mound of it or a finger-width layer even if the surface is left untouched for years whereas other “powdery” substances (like snow) can form layers of all sizes. Why is that?

In: Earth Science

First snow isnt really airborne and does stick to itself pretty well. Dust simply gets blown off when there is a strong enough wind.

Second it might simply be a matter of not having enough dust around. If you’ve ever been to a really dusty environment like a steel plant you would have seen layers of dust in some crevices were nobody ever looks.

In order for it to get thicker you would need people to never clean and move slowly so as not to disturb it. By just having people come and go and bring dirt from outside on their clothes and for them to never shower, you’ll get your thick layers. But most people don’t live like that.

Like someone said, dust is usually disturbed before it does pile up. Years ago I was underneath a steel plant’s blast furnace – this wild deep foundation pit where everything was made out of bricks – and found dust layers that were over an inch deep on some surfaces. I remember finding some dust graffiti that dated itself, somewhere around 10 years old at that time since someone had stood where I did.