Why isn’t Fukushima glowing green from the radiation?

First and foremost, that’s such a ridiculous question that only an absolute moron or a troll would actually ask. Second, this question was asked in a place where morons and trolls exist in abundance: Yahoo! Answers. As I facepalmed myself and went back to searching for the latest news on the ongoing tragedy in Japan, I began to ponder as to why radiation is always portrayed as having a green glow in entertainment. There’s absolutely no historical evidence to show green glows from areas affected by radiation. Hiroshima, Nagasaki, Chernobyl, Three Mile Island…all were high profile cases for radiation exposure and none emitted even the faintest of green glows. So what gives?

Let’s get this out of the way from the get-go: there are only two types of radiation that emit a glow, neither of which is green. The first is Cherenkov radiation, which emits a blue glow when a high energy beta emitter is submerged in a dense substance (like water) and enormous amounts of beta particles move faster than the photons (speed of light) which in turn creates a blue glow. The fact that Cherenkov radiation emits a blue glow under extreme circumstances automatically nixes it from the “green glow” phenomenon of radiation in pop culture. The second type is still disputed as to whether or not it is radiation or just an ionization of the atmosphere similar to the Aurora Borealis, but it has been observed in criticality accidents. Whether or not the glow observed is from radiation or just ionization, the glow is blue and not green.

So some Hollywood guy just made up the green glow thing and it’s stuck ever since? Not quite. For this we can blame Pierre and Marie Curie who were the first people to isolate radium-226 in 1898. Although this wasn’t the first radioactive element to be studied, it was the first that had a high enough concentration to be studied extensively. One of Marie Curie’s first observations of the element was that it had a “fairy-like glow,” in particular a blue one. This observation lead to the study of phosphorescent (also known as fluorescent) elements and over the next decade radium was experimented with in a variety of applications like x-rays or as an alternative to electricity-dependent light sources.

However, radium was far too expensive to be used as a light source because it cost thousands of dollars per gram and out of that gram only a small fraction could only be used in an end-product. In 1908 a paint was developed using zinc sulfide doped with copper. When bombarded with charged particles, this compound began to emit light, but a small amount of radium was added to enhanced the visibility and longevity of the glow. As a result, exposure to enough light then caused the paint to emit a green glow, not too dissimilar from modern day glow-in-the-dark products. Although dyes could be added to change the color of the glow, green was the most widely used because it was the brightest and most efficient of all the colors. As a result, from then on almost all radioluminescent products emitted a green hue and the subconscious link between radiation and a green glow was solidified in our society.

Source: Depleted Cranium