BOLE is so radioactive that every object native to the planet visibly glows.  The beautiful glow of Bole was seen as a sign of divine providence to its first settlers, a theocratic society known as the Hakuraku, who see themselves as wise judges of merit.  Native to the planet are the Tianma, a species of winged equines that greatly esteemed by the Hakuraku as heavenly emissaries.  Lest they be overwhelmed by the "holy radiation" of their home, each Bolean must wear an expensive piece of jewelry called a "wudi".  The wudi's circuitry, itself powered by radioactivity, manages to repel Bole's natural radiation in such a way that the wearer is instead surrounded by darkness.  It is only removed for special ceremonies when the pure light of Bole is fully embraced.

Well I guess the Geiger counter’s right
Should have seen what was there
And not some holy light