Researchers trying to determine the age of deceased individuals are finding success with a new method: looking in people's mouths. Nuclear bomb testing in the 1950s, it turns out, turned everyone's teeth into radioactive clocks.
Above ground nuclear tests in the middle of the Century introduced significant amounts of radioactive carbon into the atmosphere—and into all living things. And while our skin cells are constantly regenerating, the enamel in our teeth is only made once, bearing signs of the atmosphere in which they were created. Forbes explains the science: