It is common knowledge that there are dust devils and dust storms on Mars. But can we demonstrate that the atmospheric pressure on Mars, which is 0.6% of the pressure we experience on Earth, provides enough atmospheric mass to be able to suspend solid particles in the air for long periods of time, resisting the forces of gravity and natural buoyancy?
It is easy to assume the atmosphere of Mars is responsible for the dust devils and dust storms, but I'm concerned it may not be possible for such a thin atmosphere to produce these forces and effects, and I believe it may be necessary to pursue other possible causes for the dust devils and dust storms, such as static or other electromagnetic events.
NASA has shown that Martian dust is incredibly reactive to any type of electrical or magnetic forces, such as perhaps the solar wind or other forms of magnetic influence from the sun, Earth, or even Jupiter.
Martian dust is primarily iron oxide after all, therefore strong electromagnetic interaction should be expected.
Here is a good anecdote, citing observations of Mars from the Viking spacecraft:
"... the wind speeds picked up considerably—indeed, within only an hour of the storm's arrival they had increased to 17 m/s (61 km/h), with gusts up to 26 m/s (94 km/h). Nevertheless, no actual transport of material was observed at either site, only a gradual brightening and loss of contrast of the surface material as dust settled onto it."
The main question is, can we demonstrate whether or not the ultra-thin CO2 atmosphere of Mars actually has the physical ability to pull dust into the air, without the aid of other forces, under normal or even high wind velocities?
I read through some of the literature provided by Russell McMahon in his excellent response to this question. (Thank you!)
I'd like to provide some feedback, but I won't be able to fit all of this into a comment, so I'll put it up here in the question.
I started off reading the Space.com article Russell mentioned, and right off the bat I started seeing suspicious language:
"The new images from the Mars Reconnaissance Orbiter show wind-blown sand dunes moving across the Martian surface, sometimes up to several yards at a time, scientists said."
"'Mars either has more gusts of wind than we knew about before, or the winds are capable of transporting more sand,' explained planetary scientist Nathan Bridges of the Johns Hopkins University's Applied Physics Laboratory in Laurel, Md., who led the new study on the shifty sand dunes on Mars. 'We used to think of the sand on Mars as relatively immobile, so these new observations are changing our whole perspective.'"
I say this is suspicious language, because it sounds like circular or otherwise flawed logic:
- We know the atmospheric pressure, and the chemical composition of both the atmosphere and the Martian surface.
- We've observed and measured wind speeds, and determined that the wind should not be able to move sand dunes, presumably based on equations such as the classic drag equation etc.
- We then observe that sand dunes do move quite rapidly, despite the lack of sufficient wind composition.
- Therefore, the Martian wind must be able to move sand really easily, despite our earlier observations that the Martian wind really can't move much of anything at all.
- Therefore, maybe the particles bounce off the ground after they get carried into the wind, causing chain reactions over hundreds of millions of years etc. etc.
The problem with this logic, is where they say, "Martian sand dunes are moving rapidly, therefore the Martian wind must be able to rapidly move sand dunes, even though the Martian wind shouldn't be able to move sand dunes at all based on our understanding of wind drag."
For all we know, the Martian winds have little or nothing to do with sand moving around the planet.
Our previous observations and measurements of the atmospheric conditions on Mars support the idea that the wind cannot be much of a factor, even over cosmic time periods.
After all, we see dust storms begin within a period of hours/days, cover the planet for up to a month, then subside again over a period of hours/days and return to normal clear weather patterns - clearly this doesn't take hundreds of millions of years to build up a chain reaction of dust in the wind.
All the talk of dust particles bouncing on the ground and starting chain reactions sounds like faulty speculation, since it is based on the idea that there is not enough gravity to keep the dust on the ground, but somehow plenty of gravity when the dust eventually slams back into the ground with enough force to send several more dust particles back into the air. This sounds like a perpetual motion machine, i.e. a violation of the law of energy conservation.
As a scientific community, I feel like we need to acknowledge the fact that other forces must be in play, electromagnetic forces in particular. Any wind-based explanation we come up with just seems to sound like nonsense, and the dust storms and dust devils look eerily similar to various formations of electrified plasma filaments that can be reproduced in labs.
What do you think, Russell?
And what do you think, StackExchange?