Radiation and Nuclear Connection Cases
In the 1950's considerable effort was given to connecting UFO's with temporary or residual radiation. This was undoubtedly related to the technological conceit of the time that if these things were some kind of machine, they had to be atomic powered. There was also an attempt to connect the appearance of UFO's with various kinds of nuclear facilities - reactors, laboratories, and weapons depots. Despite years of checking with geiger counters, no UFO landing was conclusively found to leave behind trace radioactivity. NASA engineer Paul R Hill provided an explanation grounded in physics and engineering why UFO's might create detectable radioactivity during a sighting, but leave no residual contamination behind.