Notes from [www.thermalradiation.net/Radiation pioneers with narration 2.mp4](http://www.thermalradiation.net/Radiation%20pioneers%20with%20narration%202.mp4) - **Isaac Newton** postulated that individual "corpuscles" carried attributes of color. Glass attracted the particles and change their speed causing refraction. - Christiaan Huygens - postulated possibility of extra-terrestrial lives. Said light was made of waves not "corpuscles". - **Pierre Bouguer** - light had an exponential decay of intensity as it passes through an absorbing medium - **Johann Lambert** described exponential decay and cosine dependence of emission from a diffuse surface - **Pierre Prevost** - said all bodies emit radiation regardless of surroundings - **William Herschel** - discovered Uranus. discovered radiation beyond visible spectrum (infra red) - **Leopoldo Nobili** and **Macedonio Melloni** discovered that different surface emitted differing characteristics of radiation at same temperature. - **John William Draper** - measured intensity of energy vs. temperature. But did not realize T^4 relationship because absolute temperature scale had not been proposed - **Lord Kelvin** - proposed absolute temperature scale. Said - "*if you can't measure it and express it in numbers, your knowledge is of a meagre and unsatisfactory kind*" - **William Rankine** - another absolute temperature scale. studied steam engines - **Gustav Kirchhoff** - proposed idea of a blackbody. absorbtivity = emissivity (under certain circumstances) - **James Clerk Maxwell** - radiation is made of electromagnetic waves that travel at speed of light - **John Tyndall** - experimentalist. Different gases absorb different amount of radiation. Molecular gases (H2O, CO2) absorb more radiation than polar gases (O2,N2) - **Lord Rayleigh** - Proposed that light is scattered in proportional to 1/wavelength^4. Hence sky is blue in day and orange in sunset - **Josef Stefan & Ludwig Boltzmann** - Stefan Boltzmann law - **Wilhelm Wien** - Wiens law distribution of energy among wavelengths. 1911 Nobel prize. Got it pretty close but Planck nailed it - **Rayleigh & Jeans** proposed an approach that fell apart in lower wavelengths known as *ultraviolet catastrophe* - **Otto Lummer & Ernst Pringsheim** - showed Wien's law did not match their experiments - **Max Planck**- tweaked Wien's equation to match Lummer and Pringshiem's experiment (stuck a -1 in the denominator of Wien's equation). He said theoretical basis for that is that energy isn't transmitted continuously but sent in "packets", thus forming the basis of modern quantum physics. [[Planck's Law]] - **Shuster-Schwarzschild, Rosseland, Milne-Eddington** - radiative transfer equation - 1950s -- computer comes along. no need to mess with RTEs - **Margaret Huggins** - showed stars were suns. Showed Sirius is moving away from earth (doppler shift) Not all were the geniuses we think they were - Boltzmann - manic depressive and committed suicide because of criticism - Johannes Stark - was a Nazi sympathizer and convicted war criminal - Kelvin - Radio has no future; X-rays are a hoax; airplanes are impossible