News tagged with northern hemisphere

Atmospheric carbon levels nearing historic threshold

(Phys.org) —For the first time in human history, concentrations of the greenhouse gas carbon dioxide (CO2) could rise above 400 parts per million (ppm) for sustained lengths of time throughout much of the Northern Hemisphere ...

dateApr 24, 2013 in Environment
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How a sunset comet came to be

(Phys.org) —For a comet, visiting the sun is risky business. Fierce solar heat vaporizes gases long frozen in the fragile nucleus, breaking up some comets and completely destroying others.

dateMar 18, 2013 in Space Exploration
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