Using the Sun to Measure Temperatures of Flames in the Laboratory

Abstract

The problem of the temperature of the sun and other stars was generally solved about half a century ago when precise physical laws relating color and radiation intensity were developed, especially by Max Planck. 1 These laws hold exactly only for socalled "black bodies" radiating continuous spectra. Because in terrestrial laboratories only incandescent solids or liquids approach these conditions, no such radiator can be arranged using a substance above its vaporization temperature. The highest known boiling point is that of carbon : 3800° K or 6400° F. at atmospheric pressure.Only in the sun and stars are conditions such that spectra of incandescent gaseous masses approaching "black-body" continu-