A variety of non-invasive technologies have been used to “see behind” apparently solid walls to rooms not visited in over three millennia, including infrared thermography, 3D laser scans, drones, and muon radiography.
Of particular interest to me is muon radiography, aka muon tomography, whereby coulomb scattered, naturally occurring cosmic ray muons are used, not unlike highly energetic x-rays, to non-invasively image the interior of thick walled structures, like the pyramids.
Using muon radiography to “see inside” pharaonic tombs is not a new idea. The great Luis Alvarez used muon tomography to search for hidden chambers in the Pyramid of Chephren in Giza (none were found).
The Nobel Laureate Alvarez is also well-known for his hypothesis that the extinction of the dinosaurs some 65 million years ago was due to a collision between the Earth and a large asteroid somewhere near the present day Yucatan penisula, a collision estimated to have released a total energy over a billion times greater than the atomic bombs dropped on Hiroshima and Nagasaki.