Muon scanning hints at mysteries within an ancient Chinese wall
Physicists have found lots of scanning uses for these particles that rain down all over Earth
![A photo of the Xi'an fortress wall with the city skyline visible in the background.](https://i0.wp.com/www.sciencenews.org/wp-content/uploads/2023/01/012023_JR_muons_feat.jpg?fit=1030%2C580&ssl=1)
Muon scans are helping to find flaws and archeological surprises inside an ancient fortress wall in the Chinese city of Xi’an, which has grown and modernized since the wall was built nearly 650 years ago.
Mariusz Kluzniak/Moment/Getty Images Plus