But there’s another way we can and should think about the risk: not from the perspective of individuals, but from the perspective of the entire population. A tiny extra risk to a few people is one thing. But here we have a potential tiny extra risk to millions or even billions of people. Think of buying a lottery ticket — just like the millions of other people who buy a ticket, your chances of winning are miniscule. Yet among these millions of lottery players, a few people will certainly win; we just can’t predict who they will be. Likewise, will there be some extra cancers among the very large numbers of people exposed to extremely small radiation risks? It’s likely, but we really don’t know for sure.