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A Quantum Theory for Energy

The End of Classical Physics?

The dominant frequency of the radiation emitted from a Black Body depends on its temperature.

At the end of the 19th century most scientists thought that classical physics (built upon Newton's mechanics and Maxwell's electromagnetism) reigned supreme and could explain all aspects of matter and radiation. There appeared to be just a few things which needed to be fully understood. One of these was the nature of the electromagnetic radiation emitted from a so-called 'Black Body'. This work provided a crucial first step away from classical physics.

A Black Body is an object which continually absorbs and re-emits all the electromagnetic radiation falling onto it. A large effort was expended on measuring, and then trying to explain the spectrum of frequencies in the radiation emitted from a Black Body. The dominant frequency depended on the temperature of the Black Body but no one could find a single theory to describe the entire frequency spectrum. Theories based on existing classical ideas predicted an ever increasing intensity of radiation as the frequency of the radiation increased towards the ultraviolet domain. This was popularly dubbed the 'ultraviolet catastrophe'. Clearly, these theoretical predictions had to be wrong, otherwise the people studying Black Bodies would have been severely injured by the high intensity of radiation!


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