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Cosmic Rays III

StarDate: 
November 30, 2016

When an earthquake and tsunami damaged a nuclear power station in Japan a few years ago, engineers were pretty sure that some of the reactors suffered a complete meltdown. But they couldn’t go inside to see the extent of the damage. Instead, last year they took the equivalent of a cosmic X-ray. They used cosmic rays to map the interior of the reactors.

Cosmic rays are subatomic particles that hit Earth at almost the speed of light. Most of them appear to come from exploding stars. They strike molecules high in the atmosphere, creating showers of other particles, including muons. On average, several muons pass through your body every second.

Muons can pass through just about anything — even solid rock. So scientists have been using them to look into big objects on or below the surface. Looking at how muons pass through an object, or scatter off of it, reveals some of the object’s interior structure.

50 years ago, a physicist used muons to look for hidden chambers in the Great Pyramid of Khufu in Egypt. Since then, others have developed ways to examine cargo ships for nuclear weapons, to inspect concrete slabs and buried pipes, and to study the interiors of nuclear reactors, such as the ones in Japan.

Geologists have used muons to look deep into volcanoes, and they’re evaluating the technique as a way to find good underground chambers for storing carbon — exploring our own planet with the byproducts of exploding stars.


Script by Damond Benningfield

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