Seems to me that longer-waved electro-magnetic "waves" have a lesser
ability to pierce- or peek-through substances, BUT shorter-waved
"waves" are much-more ENERGETIC, like X-Rays, and they can "see
your bones" and all that.
The shorter the "wave," the MORE it can slice-through because of its
energy...
The longer the "wave," (like am-Radio which picks-up lightning static
bursts) the more clutter, interference, and blocking they encounter,
because they LACK the high-energies of X-Rays and Gamma-Rays and
Ultra-Violet (sunburn!) etc.
Sheldon Cooper I ain't...but I am a little bit? lololol...just chatting. :-)