Solar winds are blowing away the Moon's topsoil - NASA
Plasma storms 'sandblast' decatonnes of lunar dirt into space
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Solar winds and plasma storms are "sandblasting" the Moon, according to top NASA boffins, causing large amounts of lunar surface material to be blown off into space.
The new discoveries come to us from simulations conducted by NASA's Dynamic Response of the Environment At the Moon (DREAM) team. In particular the DREAMers modelled the effects of a large Coronal Mass Ejection (CME) - essentially a massive gale-force gust or storm in the solar wind, involving say a gigatonne of plasma being blasted out into space. Such a mighty puff of sun-wind striking the Moon can have serious effects, the lunar surface not being protected by any atmosphere worthy of name nor any magnetic field either as we have here on Earth.
“We found that when this massive cloud of plasma strikes the Moon, it acts like a sandblaster and easily removes volatile material from the surface,” said William Farrell, DREAM team lead at NASA Goddard, in a statement issued yesterday. “The model predicts 100 to 200 tons of lunar material - the equivalent of 10 dump truck loads - could be stripped off the lunar surface during the typical 2-day passage of a CME.”
The space sandblaster process is technically known as "sputtering", the word used to decribe the ejection of surface atoms when struck by plasma ions. Seemingly the ions in a CME are extra sputtersome as they have a higher proportion of comparatively heavy and more powerfully charged helium nuclei among them (as compared to your more lightweight hydrogen ones) than is seen in the regular solar wind.
The NASA DREAM crew are particularly keen to flag up their research as this is a time of major budget crunch at the US space agency and they are plainly worried that the Lunar Atmosphere And Dust Environment Explorer (LADEE) - a lunar orbiter mission scheduled to launch in 2013 - might be in line for the chop so as to let America afford such efforts as the Webb Space Telescope and the Shuttle- and Apollo-retread Space Launch System manned mega-rocket.
The DREAM team plainly consider that this would be a mistake, the more so as the sandblaster simulations perhaps mean that the LADEE - zooming along in the clouds of lunar topsoil sent boiling up into moon orbit by CMEs - would be nearly as good as having a lander.
“This huge CME sputtering effect will make LADEE almost like a surface mineralogy explorer, not because LADEE is on the surface, but because during solar storms surface atoms are blasted up to LADEE,” argues Farrell.
The NASA boffins also suspect that CME-driven sputtering could have major effects on the thin atmosphere of Mars, the red planet being largely unprotected magnetically. ®
