[mohn]

> Hounsfield pondered whether it was possible to detect hidden areas in Egyptian pyramids by capturing cosmic rays that passed through unseen voids.

I also wondered about this possibility a few years ago and when I searched online, I found an example of muon tomography of the volcanic dome of La Soufrière on the island of Guadeloupe[1]. Cool non-seismic approach to a difficult imaging problem.

Specifically, I was wondering about neutrino tomography of the entire earth, but the low probability of neutrino collisions would seem to make that infeasible.

[1] https://www.youtube.com/watch?v=CPYhqJ3e-2o

[yodon]

A team from Berkeley led by Luis Alvarez used Cosmic Rays to image the inside of the Great Pyramid in the 1960's[0]. tl;dr it's solid rock. My favorite story from the effort was they briefly had incredible excitement because they found a chamber. The excitement lasted until they realized they had neglected to include the room where the detectors were located, which the system detected correctly, in their analytical model of the structure (providing their method was able to identify unpredicted rooms in the structure).

[0]https://www.science.org/doi/abs/10.1126/science.167.3919.832