I have a question about Planck's Law. When I first read about it, I misunderstood it to mean that an object at a certain temperature would only emit a very narrow wavelength of light. But as I've looked into it further it appears as though everything in the universe emits a range of light that looks like a bell curve, and Planck's Law only specifies the peak wavelength of a black body at a given temperature. Right? Okay, so check out this graphic of black bodies of various temperatures (this is a pretty typical graphic used in black body description pages on the Internet): [URL]http://upload.wikimedia.org/wikipedia/commons/1/19/Black_body.svg[/URL] It would appear to imply that everything in the universe emits all wavelengths of light; that even the weakest parts of an object's spectrum are still not zero. If that's the case, then can I assume that human beings must emit visible light (in addition to their IR peak)? I know the retina is sensitive enough to respond to a single photon, but it appears that 5 - 9 photons are required within a 100ms or so to actually register a response in the brain. So are all the people around me giving off visible light that I'm not seeing? If so, that's awesome. If not, what am I missing?