Fluid transport on Earth and aeolian transport on Mars |
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| Authors: | Carl Sagan RA Bagnold |
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| Institution: | Laboratory for Planetary Studies, Cornell University, Ithaca, New York 14853, USA;Rickwoods, Mark Beech, Edenbridge, Kent, England, UK |
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| Abstract: | Experimental data on cohesion-free particle transport in fluid beds are applied, via a universal scaling relation, to atmospheric transport of fine grains on Mars. It may be that cohesion due to impact vitrification, vacuum sintering, and adsorbed thin films of water are absent on Mars—in which case the curve of threshold velocity versus grain size may show no turnup to small particle size, and one micron diameter grains may be injected directly by saltation into the Martian atmosphere more readily than 100 micron diameter grains. Curves for threshold and terminal velocities are presented for the full range of Martian pressures and temperatures. Suspension of fine grains is significantly easier at low temperatures and high pressures; late afternoon brightenings of many areas of Mars, and the generation of dust storms in such deep basins as Hellas, may be due to this effect. |
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