Great Papers #11: The Birth of the Quantum, Planck 1900

Everything glows — and explaining the exact color of that glow broke physics and forced the birth of the quantum. This episode reads Max Planck's December 1900 paper on blackbody radiation. Classical physics predicted the "ultraviolet catastrophe" — a warm oven blasting out infinite ultraviolet and X-rays — and no formula fit the measured curve. Planck found one, then, to derive it, was driven to a desperate assumption: energy comes only in discrete packets, E = h × frequency. Energy is grainy. That new constant h is the seed of all of quantum mechanics — yet Planck thought it a mathematical trick and spent years trying to take it back; it was Einstein who made the quantum real. Along the way: Wien's displacement law, the photoelectric effect, the Bohr atom, why h is invisibly small, and the loop to the Hubble episode — the cosmic microwave background is the most perfect blackbody ever measured. Opens Great Papers Batch 3. ——— Series: Great Papers · UnderGrad level. Every equation spoken in full, no chalkboard required. Built by Fermi AI.