Then I told my mom about it. She said “Duh. You just now know?” 😀
For comeback, I told her (again, credit to Mudpie for telling me) that banana is used as a unit in measuring radioactivity. Like all foods (and living things, including you), banana radiates. It just happens that banana contains the radioactive isotope Potassium-40 (19 protons and 21 neutrons, 1 neutron more than stable Potassium) which makes it radiate a little bit more than other things. Fortunately for us the half life of Potassium-40 is over a billion years, so the amount of radiation a banana produces is less than 1/365 times the increase in cancer risk caused by 40 tablespoons of peanut butter.
In short, bananas may cause false alarm on nuclear radiation sensors at US ports, but it’s perfectly safe to eat one or two of them per day. 🙂 Or, if you’d like a stronger radiation dose, smoke one cigarette per year.