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2 May 2016
NASA scientists have come up with a new model (click here) to explain the mysterious swirls that appear to be painted on the Moon’s surface.
These “lunar swirls” can be tens of kilometres across and appear where ancient bits of magnetic field are embedded in the lunar crust – although not every time....
...The third theory says that, since electrons and ions in the solar wind are electrically charged, they respond to magnetic forces and that the magnetic field on the Moon could shield the surface from weathering by the solar wind.
The new research looked closely at the third of these theories, relying on new observations by the Lunar Reconnaissance Orbiter (LRO). But scientists found some problems when it came to modelling the theory.
“The problem with the magnetic shield idea is that the embedded magnetic fields on the Moon are very weak – about 300 times weaker than Earth’s magnetic field,” said Bill Farrell of NASA Goddard.
“It’s hard to see how they would have the strength to deflect the solar wind ions.”
But what the new models did show was that the magnetic field could create a strong electric field when the solar wind attempts to flow through.
And this powerful electric potential could deflect and slow particles in the solar wind, reducing weathering on the surface of the Moon, leaving brighter regions where it was protected.
The new models are published separately as a series of three papers, one in Icarus on March 1, 2016 by lead author Andrew Poppe of the University of California, Berkeley; one in the Journal of Geophysical Research: Space Physics on June 18, 2015 by lead author Shahab Fatemi of University of California, Berkeley; and one in the Journal of Geophysical Research: Planets on November 25, 2015 by lead author Michael Zimmerman of The Johns Hopkins University.
But the research has not ruled out the other two theories....
