Kudos to you on the Mencken quote. Another apt one: "Immorality is the morality of those who are having a better time."
Ra-di-a-tion. Yes, indeed. You hear the most outrageous lies about it. Half-baked goggle-box do-gooders telling everybody it's bad for you. Pernicious nonsense. Everybody could stand a hundred chest X-rays a year. They ought to have them, too.
Variables don't; constants aren't.