Max Planck and the Ultraviolet Catastrophe

In the late 1800’s physics ran into a road-block in the understanding of the universe. 

Here’s the problem: if a generic thing (physicists call it a black-body) is heated, it will release its energy in the form of radiation (light and heat). It was assumed that such a “body” would emit energy at all wavelengths - that is, the light released would be a smooth rainbow of color. Physicists at the time could predict the amount of energy the body would release at each wavelength, but only up to a point. Once the math was applied to wavelengths in the ultraviolet range (and beyond) the math failed horrifically. In fact, the math predicted that an object would give away virtually ALL of its energy and, thus, approach absolute zero. This was clearly wrong.

Max Planck discovered he could “fix” the math by inserting a constant he called h. While being able to fix the math is great and the constant bears his name (Planck’s constant : 6.6262x10-34 J⋅s) the most important part of his work (for our purposes) is not the number itself, but rather it is what the existence of this constant implies. 

In English, his “fixed” math formula said that energy was quantized - that is, it could only exist as multiples of a small amount. An easy analogy of this is American money. All amounts of currency you can spend, earn or hold are multiple of the penny. A gas station may claim that gas costs $2.789, you never pay tenths of cents - they round up.

This math “fix” is thus responsible for the beginnings of Quantum Physics.