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?
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 ;-).