If I make a ball out of calcium; drill a little hole in it; then heat it up in a suitable [vacuum] environment; I see black body radiation thru the little hole, right? At least up to the melting point of calcium ?? I mean, black body radiation is independent of material, right ? Yet the "emission spectrum" of calcium is dark brilliant red. That is what you see if you put calcium in a flame. So when do you get black body radiation? Only below "emission spectra" temperatures? How come I found a chart of black body radiation for 5500 degrees Kelvin?? [ Wikipedia I believe] Related question: the NASA COBE experiment was measuring black body radiation, right?