The cold war with its nuclear threats left its mark on the American psyche. Mention radioactivity, and panic strikes. Yet, hard radiation abounds in nature. Some of it is harmful to our health, but we've long since learned that living is a dangerous occupation, and natural radioactivity is far from the worst hazard.
Did I mention that you are radioactive? It comes with living. Cosmic
rays from space strike nitrogen in the atmosphere, changing a minute amount of it into
a radioactive form of carbon: carbon 14. Plants use all kinds of carbon in their
manufacture of food, and we eat plants, including the carbon 14 they incorporated into
their being. Since this has been going on practically forever, obviously this is not an
atomic catastrophe. Since carbon 14 slowly turns back into nitrogen, the amount left in
a once living organism can tell us how long it's been since that animal or plant
was alive. Much of the dating of the Chihuahuan Desert's biological events of the
last 50,000 years is courtesy of this ubiquitous carbon 14.
Listen to the Audio (mp3 format) as recorded by KTEP, Public Radio for the Southwest.
Contributor: Arthur H. Harris, Laboratory for Environmental Biology, Centennial Museum, University of Texas at El Paso.
Desert Diary is a joint production of the Centennial Museum and KTEP National Public Radio at the University of Texas at El Paso.