Why are Hiroshima and Nagasaki safe to live while Marie Curie’s notebook won’t be safe to handle for at least another millennium?

Question

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

Answer 1

For the most part, the cities were just exposed to intense radiation, which doesn’t necessarily turn things radioactive, at least not in a way that has a long half life. Curie ground up pitchblende to extract the radium in it, and so radium dust was everywhere. Her notebooks were thoroughly contaminated with it over the years, and that radium remains radioactive.

So if we’d taken the radioactive material from the bombs, ground it up and sprayed it all over the towns, they’d probably still be radioactive.