I have 2 questions. 1)Can a gray body irradiate more than a black body for a given wavelength if both bodies are at the same temperature? 2)If the answer to the previous question is yes, do you know any material that irradiate enough in the visible spectrum that we can see it with our eyes for a room temperature (about 300 K)? ------------------------- M thoughts: 1)I think the answer is yes. It would explain the graph of http://en.wikipedia.org/wiki/File:EffectiveTemperature_300dpi_e.png, i.e. that the Sun irradiates more than a black body in most part of the visible spectra, even though both the Sun and the black body have the same temperature. 2)I have no idea but I find this interesting. I'd love to see some material emitting enough in the visible spectra for us to see it and touch it (low temperature).