On Earth, wind blown dust storms generate powerful electric fields of up to 200 kV/m, with the ground becoming positively charged and the dust particles negatively charged.
The mechanism behind this is poorly understood but various scientists have assumed that a similar process takes place on Mars and that it leads to bizarre phenomenon.
One idea is that the excess electrons in dust break down methane in the atmosphere. Methane is a potential biological marker so estimating how much is produced is important.
The significance of this is that any methane we see in the martian atmosphere today must have survived both this and the ravages of sunlight.
Another idea is that the excess electrons catalyse the production of hydrogen peroxide in the atmosphere which then falls as a unique and rather nasty form of Martian snow.
But both these ideas are probably wrong, say Jasper Kok and Nilton Reno at the University of Michigan today. They’ve put together the most advanced model to date of how windblown dust on Mars becomes electrified and worked out how it affects the atmospheric chemistry.
“We find that the production of hydrogen peroxide and the dissociation of methane by electric fields are much less significant than previously thought,” they say.
Another thing that electrification leads to is lightning and there has been precious little evidence of that on Mars, which perhaps backs this team’s claims.
So it looks as if electric fields play a much smaller role in the Martian atmosphere than they do on Earth
Shame really, hydrogen peroxide snow sounds cool.
Ref: arxiv.org/abs/0901.3672: The Electrification of Wind-Blown Sand on Mars and its Implications for Atmospheric Chemistry