I was wondering if anyone could answer this question.
Can radar of whatever sort penetrate the pyramids?
Radar will not work, neither will sonar or cosmic rays, or X rays or even exotic particles. (which can pass through anything).
The reason, is that the whole pyramid is built from fairly loose fitting stones with irregular air spaces in between. While the visible casing stones
fit together extremely well, the hidden bulk of the pyramid is not so well put together.
The idea of radar or sonar is that some of the signal is reflected whenever the density of the medium through which the signal passes changes. So you
can readily detect objects in air or water, or with a bit more difficulty, objects buried in the ground.
But in a huge pile of loosely fitting rocks there are so many irregular air/rock interfaces, that the signal becomes reflected and confused to the
point that detecting any significant structure within is just not possible.
Like trying to locate a single small air bubble hidden within a large piece of foam rubber.
It could only work if the pyramid were made of some solid homogeneous material like solid concrete. Then you may have a slight chance of locating
chambers or tunnels by transmitting "something" through the structure. Many people have already tried all sorts of different ideas, but nothing so
far has worked.
The most useful tool so far has been ground penetrating radar. This works pretty well in "solid" sand outside and around the pyramid. But it has
proved completely useless within the loosely packed pyramid structure itself.