Calling space scientists and aficionados--Martian weather

Factual Questions
1

We always hear of sandstorms on Mars, and I remember that when Viking arrived in orbit in 1975 that the entire planet was shrouded in windborne dust and sand.

But how can that be? The atmosphere is only 1% as thick as
Earth’s. How can winds raise sand and dust? And while we’re on it, how could our last two lost spacecraft “burn up in the atmosphere”, as has been speculated?

2

Despite having such a wispy atmosphere, Mars still is able to have high velocity winds. These winds are able to pick up very fine dust, and blow it easily around, and yet the winds are not even strong enough to push over a person standing on the surface.

Thinking of a sandstorm on earth is a bit different. The air density is sufficient to pick up larger bits of sand in our deserts, plains, etc, but the air density on Mars can not do this. It is only strong enough to pick up very VERY fine particles.

3

Also, I think that the atmosphere density isn’t that slight… and even thin as it is, it’s still suffecient to burn up fragile man-made devices.

Now, once my company finishes terra-forming it, things will be much better. I’ll be selling land grants, about the size of Rhode Island.

4

most ‘stuff’ burns up in earths upper atmosphere where the air density is much lower also.

5

javaman:

Several things:

  1. Yes, Mars’s atmosphere is much thinner than Earth’s. But the differences in temperature between latitudes are greater, which allows the winds to rev up to much greater velocities than on Earth, which gives them considerable dust-raising potential.

  2. Much of the mass of dust particles on the Martian surface is very, very fine: about as fine as particles of smoke here on Earth! So it wouldn’t take much wind to get it going.[sup]1[/sup]

  3. Martian surface gravity is only 38% of Earth’s, so again, the dust is easily blown around.

  4. At the speed of an incoming spacecraft, the friction caused by a 1%/Earth atmospheric density is still plenty enough to burn up said aircraft.
    [sup]1[/sup]The dust on Mars is so fine, in fact, that while future colonists may be able to stand the cold, the low atmospheric pressure, and the lack of oxygen, silicosis may turn out to be the downfall of a human Martian civilization.