2023-08-30 11:16:40
Lunar Surface Areas Under Study – PSI
MADRID, 30 Ago. (EUROPA PRESS) –
A new study of lunar eddies shows evidence of a highly mobile regolith on the Moon. The regolith is the layer of unconsolidated materials that rest on solid rock.
Lunar eddies are one of the enigmatic formations that occur on the surface of the Moon associated with local magnetic anomalies. They are characterized by a high albedo, an immature geological appearance, and often present a sinuous shape from which they take their name.
The processes involved in its formation have been examined and debated since its discovery.. The most popular idea is to ‘shield’ the surface from solar wind radiation by the associated magnetic anomaly. This explains the swirling pattern, since the shielded material would be brighter than the irradiated materials outside of the magnetic field. However, the spectral properties do not always match what is expected of ‘shielded’ materials.
Another hypothesis is that electrostatically levitating dust is preferentially segregated and trapped by the magnetic field. Electrostatically levitated lunar dust is the smallest portion of lunar dust, which on the Moon is intrinsically composed of minerals brighter than larger ones, which are more difficult to move electrostatically.
The darker dust includes tiny inclusions (tiny bits of material within a grain made of a different material than the grain itself) of nanometer-scale iron, thought to be magnetically separated and deposited in the dark areas of the eddies. One way to produce this iron on a nanometer scale is through radiation from the solar wind.
Then what is? One way to answer this question is to examine the texture of the surface. Texture is the roughness and porosity of the soil grain to grain (or in this case dust to dust) and the structures within grains (such as inclusions). A group of scientists from PSI (Planetary Science Institute) examined the surface texture in a region of Mare Ingenii using photometric analysis tools.
Photometric analysis is based on how material scatters light and how those scattering properties change as lighting (angle of sunlight relative to the surface) and viewing (position of your spacecraft) geometries change. What they found is that the intergrain roughness was similar throughout the eddy region, but that the soil in the dark lines has grains with a more complicated structure.
Furthermore, they also show that the composition between the light and dark areas is different, following the expectations of dust collection and segregation.
“The evidence, including the recent correlation of topographic minima with the bright areas of eddies, tells the story that more than one process is involved in their formation,” he said. it’s a statement lead author, Deborah Domingue. “We definitely see evidence that bright areas are less irradiated, but this doesn’t explain all of the eddies’ properties. Something else is at work, and the textures suggest that dust collection and segregation are part of the story.”
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