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  When is a leaf like a meteoriteMar 20, 2019 9:56 PM PDT | url
 
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That oldish leaf mostly sunk into the snow in my yard on a melty day last week reminded me of a late February BBC article about a UK meteorite-hunting expedition to Antarctica.
 
About 2/3rds of the world's collected meteorites have been picked up in Antarctica, where the dark, scorched rocks stand out in sharp relief against the snow, and are naturally brought to the surface in areas where the glaciers in which they land move over ridges.
 
But iron meteorites, about 5% of the meteorites found elsewhere in the world, make up only 0.5% of the meteorites found in Antarctica—and the expedition's science team theorizes that this is simply because, being metal and thus more readily conductive of heat from any sunlight that strikes them, any iron meteorites that come to the surface are much more likely than rocky meteorites to melt their way back beneath the surface, where they may remain hidden within a mere 30cm of the surface (the team is devising a metal-detecting sweep to find them).
 
So anyway, while that dead old leaf probably isn't metal and thus not as efficient a conductor as an iron meteorite, it does seem to have heated up a bit in the sunlight—darker stuff being dark because it absorbs incoming photons rather than reflecting them, heating up in the process—and begun the process of melting downward through the snow...probably somewhat slower than an iron meteorite would. : P
 
...So I can only assume that all the iron meteorites in my yard were already hidden.
 
 
 
 
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