As you've probably gathered from even a little reading, there isn't such a thing as "amount of radiation."

Much depends on the energy levels, kind of sheilding, kind of particle, time of exposure. For instance, you could stand near a pile of depleted uranium in total comfort. If you were daring, you could even EAT a handful. Most of the energy is released via Alpha particles that have too little oomph to penentrate your skin. But if you got any DU in your bloodstream, the stuff has a nasty habit of collecting in a few places so it can irradiate some of your internal organs at close range.

Cosmic rays get mentioned a lot because their energies are very high; they can slam through light shielding and in metals give rise to secondary radiation (as I understand it...feel free to correct me, fellows!) The sun is better behaved, except during flares where the kinds of particles released changes and the amount increases radically.

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"You keep using that word. I do not think it means what you think it means."