Kirchhoff's law of thermal radiation rarefied material such as air, or transparent material, through which observations can be made. The interface is not a material body and can neither emit nor absorb. It is a mathematical surface belonging jointly to the two media that touch it. It is the site of refraction of radiation that penetrates it and of reflection of radiation that does not. As such it obeys the Helmholtz reciprocity principle. The opaque body is considered to have a material interior that absorbs all and scatters or transmits none of the radiation that reaches it through refraction at the interface. In this sense
A Moving Sound of the human condition." A Moving Sound has attracted international attention for opening doors to the under explored territory of Far Eastern music. The group is intensely passionate about how it presents the use of traditional instruments in its contemporary sound. Their approach is to be holistic – combining art, spirituality, social awareness, and a universal love of humanity play key roles in the creative process. According to Tom Pryor, music supervisor for National Geographic, "A Moving Sound is one of the most original outfits working in the world music arena today, an inspired marriage of Taiwanese traditional sounds and