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After spending hours understanding what exactly Black Body radiation and Ultraviolet catastrophe is, I cannot help myself asking what was the reason that scientists such as Wilhelm Wien and Max Planck studied Black Body Radiation in the first place? What intrigued them to study a hypothetical situation? What were they looking for exactly that made them study this phenomenon?

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In the late 19th century physics seemed more or less complete, in the sense that it explained everything that could be measured. However when applied to a black body the accepted physics of the day predicted that the black body would emit an infinite amount of energy, and this was obviously in conflict with experiment. There's nothing hypothetical about this - theory predicted one thing and experiment measured something different.

This is an exciting situation for any ambitious physicist because it means that something must be wrong with the existing theory. Indeed, resolving the problem required the creation of quantum mechanics, and immortality for Max Planck (Wien is less of a household name, but he still has a law named after him ;-).

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  • $\begingroup$ Thanks for your explanation. Can you also mention what was Einstein role in this study? Did he work on this field too or his work was just limited to General and Special Relativity. Cheers $\endgroup$ – bman Jul 24 '13 at 6:30
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    $\begingroup$ See galileo.phys.virginia.edu/classes/252/black_body_radiation.html. Einstein's work was an essential step in clarifying Planck's law and understanding why it worked. Einstein was the first to realise that quantisation of radiation was a universal phenomenon. $\endgroup$ – John Rennie Jul 24 '13 at 6:34
  • $\begingroup$ This answer is false & perpetuates a common myth found in intro physics textbooks. First, people were working on black body way before UV catastrophe (it is in 1858/58 that Stewart and Kirchhoff developed their laws of black body radiation). Second, UV catastrophe in no way motivated Planck, who did not accept the equipartition principle as foundational. See for example Helge Klagh's short piece on the relevant history. I wish you hadn't answered this question, so someone could give a right answer since I am curious about it. $\endgroup$ – Artem Kaznatcheev Dec 5 '16 at 22:59

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