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Atomic Tune-Up: How the Body Rejuvenates Itself

On <em>Star Trek,</em> Dr. Leonard McCoy, played by actor DeForest Kelley, never wanted to be beamed anywhere because he worried it would scatter his atoms across the universe.
Hulton Archive/Getty Images
On Star Trek, Dr. Leonard McCoy, played by actor DeForest Kelley, never wanted to be beamed anywhere because he worried it would scatter his atoms across the universe.

For most people, a makeover means losing weight and getting new clothes, hair and makeup.

But what they may not know is that the body does its own extreme makeover regularly. In fact, 98 percent of the atoms in the body are replaced yearly.

Researchers in the 1950s made the discovery by feeding their subjects radioactive atoms. Using radiation detectors, the researchers watched the atoms move all over the body. They found that the new atoms replaced old ones and ended up in all tissues of the human body.

But these atomic makeovers prompt a more philosophical question: Are people really themselves if their atoms are always new, or are they new people each year? David Kestenbaum tackled that philosophical question — and discussed atomic makeovers — with the experts.

Copyright 2023 NPR. To see more, visit https://www.npr.org.

David Kestenbaum is a correspondent for NPR, covering science, energy issues and, most recently, the global economy for NPR's multimedia project Planet Money. David has been a science correspondent for NPR since 1999. He came to journalism the usual way — by getting a Ph.D. in physics first.

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SOMOS CONNECTICUT is an initiative from Connecticut Public, the state’s local NPR and PBS station, to elevate Latino stories and expand programming that uplifts and informs our Latino communities. Visit CTPublic.org/latino for more stories and resources. For updates, sign up for the SOMOS CONNECTICUT newsletter at ctpublic.org/newsletters.

SOMOS CONNECTICUT es una iniciativa de Connecticut Public, la emisora local de NPR y PBS del estado, que busca elevar nuestras historias latinas y expandir programación que alza y informa nuestras comunidades latinas locales. Visita CTPublic.org/latino para más reportajes y recursos. Para noticias, suscríbase a nuestro boletín informativo en ctpublic.org/newsletters.

The independent journalism and non-commercial programming you rely on every day is in danger.

If you’re reading this, you believe in trusted journalism and in learning without paywalls. You value access to educational content kids love and enriching cultural programming.

Now all of that is at risk.

Federal funding for public media is under threat and if it goes, the impact to our communities will be devastating.

Together, we can defend it. It’s time to protect what matters.

Your voice has protected public media before. Now, it’s needed again. Learn how you can protect the news and programming you depend on.