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Author Topic: If gamma rays are so penetrating, why can our atmosphere stop them?  (Read 2805 times)

Offline mcjhn

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if our atmosphere is so good at stopping gamma rays why do we need thick lead/concrete walls in nuclear reactors?

is it because 3km of gas is equivalent to a thick lead/concrete wall?

or not many gamma rays to start with compared to a nuclear reactor?

or something else?

thanks!

mark



 

Offline JP

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is it because 3km of gas is equivalent to a thick lead/concrete wall?

or not many gamma rays to start with compared to a nuclear reactor?

Certainly, the atmosphere has as much stopping power to gamma rays as a very thick piece of lead.  Source: NASA (http://imagine.gsfc.nasa.gov/docs/ask_astro/answers/970718.html)

(It's much thicker than 3 km, by the way--roughly 100 km thick). 
 

Offline CreativeEnergy

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Of course, if you had a gamma-ray burst (GRB) resulting from the core collapse of an extremely massive star in close proximity to the Earth with one of its bipolar jets aimed directly at the Earth, then it would be an entirely different story. The surface of the Earth would quite literally be sterilized.

But other than that, JP is correct. ;)
 

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