Muons II 
The Mayan city of La Milpa, in Belize, has been abandoned for more than a thousand years. Dense jungle covers the city, including a pyramid that towers seven stories high. Yet archaeologists hope to look deep into the pyramid this spring and summer. Their tools aren’t picks and shovels, but electronic detectors and particles created high above Earth’s surface.
The particles are muons. They’re created when particles from exploding stars slam into atoms in Earth’s atmosphere. The muons can penetrate deep into solid rock. That allows them to act like X-rays - instruments can detect the muons after they’ve passed through an object, creating an image of its interior.
The technique was developed by Luis Alvarez. In 1967, he used a muon detector to search for hidden chambers inside the pyramid of Khafre in Egypt. The experiment found no hidden chambers, but it did confirm that the technique would work.
Since then, scientists have used muons to probe the Pyramid of the Sun at the ancient city of Teotihuacan in Mexico. They’ve also used it to look deep into volcanoes that may be about to erupt. And now, physicists from the University of Texas at Austin are setting up detectors at one of the pyramids of La Milpa.
Muons aren’t exactly like X-rays. They don’t provide the same level of detail, and it can take weeks to gather enough muons to produce a good picture. Even so, they provide a way to probe the hidden past - with the help of exploding stars.
Script by Damond Benningfield, Copyright 2013