00:00like science fiction every minute about 10 000 muons ghostly particles born when cosmic rays
00:07strike the upper atmosphere rain down through every square meter of the earth they pass through
00:12rock through flesh through everything but dense solid stone absorbs more of them than empty air
00:19so if you place detectors beneath the pyramid and count the muons arriving from every direction
00:25you can build a map of density inside the stone solid limestone lets fewer muons through
00:31a hidden chamber lets more through casting what physicists call a muon shadow it is in effect an
00:39x-ray
