Today, we go to a spot that may be one of the most philosophical places in the universe: the thymus, an organ that knows what is you, and what is not you. Its mood may be existential, but its role is practical — the thymus is the biological training ground where the body learns to protect itself from outside invaders (think: bacteria, coronaviruses). But this training is not the humdrum bit of science you might expect. It’s a magical shadowland with dire consequences.

Then, we’ll leave the thymus to visit a team of doctors who are using this organ that protects you as a way to protect someone… else. Their work could change everything.

Special Thanks:

One thousand thanks to Hannah Meyer, Salomé Carcy, Josh Torres, and Cold Spring Harbor Laboratory for showing us a real-life (mouse) thymus for this episode. Special thanks also go to Diane Mathis and Kate Webb.

Further reading:

Wanna do a little light reading? Here’s the immunology textbook Jenni Punt and Sharon Stranford helped write, including a whole section on that funny little thing called AIRE! Kuby Immunology

The science paper that first described what happens inside the thymus as an, “immunological self shadow”.

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As our co-Hosts Lulu Miller and Latif Nasser are out this week, we are re-sharing the perfect episode to start the summer season!

This one, which first aired in 2014, tells the strange story of a small group of islands that keeps us wondering: will our most sacred natural landscapes inevitably get swallowed up by humans? How far are we willing to go to stop that from happening?

This hour is about the Galápagos archipelago, which inspired Darwin’s theory of evolution and natural selection. Nearly 200 years later, the Galápagos are undergoing rapid changes that continue to pose — and perhaps answer — critical questions about the fragility and resilience of life on Earth.

Episode Credits:Reported and produced by Tim Howard.

Radiolab is supported by listeners like you. Support Radiolab by becoming a member of The Lab (https://members.radiolab.org/) today.

Our newsletter comes out every Wednesday. It includes short essays, recommendations, and details about special events. Sign up (https://radiolab.org/newsletter)!

Follow our show on Instagram, Twitter and Facebook @radiolab, and share your thoughts with us by emailing radiolab@wnyc.org.

Since the massacre that took the lives of 19 schoolchildren in Uvalde, Texas, people across the world began to ask versions of one question: why did police wait outside the door instead of protecting the kids?

It's not the first time this question has come up. Two years ago, as she watched police respond to the protests that followed the death of George Floyd, Producer B.A. Parker wondered: what are police for? With the help of our Producer Sarah Qari, she found that the United States’ Supreme Court had given this a most consequential and bewildering answer.

We decided to re-air this episode to shed light on how a case from 2005 upended our assumptions about the role police are meant to play in our lives.

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