Muons are similar to electrons — the tiny particles that zip around atomic nuclei — but are 200 times more massive; hence their nickname, "fat electrons." These fat electrons can penetrate ...

Muon tomography, or muography, is the practice of using muons generated by cosmic rays interacting with Earth’s atmosphere to image structures on Earth’s surface, akin to producing an X-ray.

For those still curious, here's the answer — this was the world's first test of using cosmic radiation, specifically muons, to assess the condition of a bridge open to traffic. "These particles are ...