Why are Hiroshima and Nagasaki safe to live while Marie Curie’s notebook won’t be safe to handle for at least another millennium?
In: Physics
Because radiation is very poorly understand by most people. Not all radiation is created equal. Not all radioactive materials are the same.
In the case of a nuclear bomb, most of the danger comes from the intermediate fallout products created in the explosion. These are dangerous, but the reason they are dangerous is that most of them experience radioactive decay relatively quickly. So if you happen to be close enough to the bomb when it goes off, you will receive a massive dose of radiation. Of course, the people who are affected by this the strongest also tend to become vaporized by the bomb itself, so the number of people who are close enough to be radiated without being close enough to be instantly killed is relatively low.
More dangerous are the fallout products that have a similar radioactive half-life, but that are biologically important elements. Iodine is one such element, and I-131 is created in nuclear explosions. If you happen to be low on iodine when you inhale fallout products, your body my uptake the iodine and incorporate it into your body, constantly dosing you until the iodine is eventually flushed from your body. This is why governments usually give out iodine pills after nuclear incidents – they’re trying to saturate your body’s iodine levels so that you won’t absorb the radioactive iodine.
But the flip side of this is that most of the ionizing fallout products decay into inert materials relatively quickly. Nuclear explosions produce relatively small amounts of really long-lived fallout products, so the radiation from the bombs in 1945 has pretty much all decayed into inert materials. If you’re worried about exposure to radiation, Denver is actually more dangerous than either Hiroshima or Nagasaki.
Marie Curie’s notebooks, on the other hand, are mostly contaminated with radium. The isotopes in her notebook have a half-life of about 1600 years, so they’re essentially as radioactive now as they were when Curie contaminated them.
If you’re just going to see her notebook, there’s very little risk. You get more radiation exposure from a long plane flight than you do her notebook. However, if any of the radium flakes out and gets into your lungs, you’ll be getting constant doses of radiation until the radium is flushed from your body. So there is a level of risk if you’ll be sharing air with the notebook, or if you’ll be exposed to it for a long time.
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