Knowra Space weathering Space weathering Space weathering is the gradual alteration of airless bodies’ surfaces by solar wind, micrometeorite impacts, and radiation. It darkens and reddens many silicate surfaces and changes their reflectance spectra.
Solar wind : A stream of charged particles flowing outward from the Sun. Its ions implant into grains and sputter atoms from exposed surfaces.
Lunar soil : The loose layer of fragmented rock and dust covering the Moon’s surface. It preserves mature examples of impact glass, implanted ions, and nanophase iron.
Apollo program : A NASA human spaceflight program that landed astronauts on the Moon between 1969 and 1972. Returned lunar soils provided the first abundant samples for studying space-weathered grains.
Chemical weathering : The breakdown or transformation of minerals through reactions with water, gases, or other chemicals. Unlike space weathering, it commonly depends on liquid water or reactive atmospheric constituents.
Micrometeoroid : A small meteoroid, typically dust-sized, traveling through space. Its impacts melt or vaporize surface material, forming glass and vapor deposits.
Lunar swirls : Bright, sinuous surface patterns on the Moon with distinctive magnetic and spectral properties. Their contrast with surrounding terrain has been linked to locally reduced solar-wind exposure.
Lunar meteorite : A meteorite ejected from the Moon by an impact and later recovered on Earth. These samples complement Apollo collections with material from additional lunar locations.
Solar radiation pressure : The force exerted on a surface by momentum carried in sunlight. It is another solar influence on small bodies, but moves material rather than chemically altering grains.
Sputtering : The ejection of atoms from a solid surface after energetic particle impacts. Solar-wind ions remove atoms from exposed grains through this process.
Regolith : A layer of loose, unconsolidated material covering solid planetary or asteroidal rock. Weathering modifies grains within regolith rather than altering only coherent bedrock.
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