金沙国际唯一指定官网

Doomsday spring

作者:苏羌    发布时间:2019-03-07 06:10:16    

By Jeff Hecht PROPHETS of doom have another disaster to tout. If a large comet or asteroid smashes into Earth, a searing “ultraviolet spring” would follow the devastating “impact winter”. An asteroid ripping through the atmosphere would ionise nitrogen and oxygen. The nitric oxide that forms then destroys the stratospheric ozone that shields us from damaging ultraviolet light. Dust thrown up into the atmosphere would protect the surface for a while, but once it had settled, survivors would face elevated ultraviolet levels that could suppress photosynthesis and damage DNA,

 

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