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Planck Presents Quantum Hypothesis

| Quantum Theory

Max Planck presents his blackbody radiation formula to the German Physical Society (DPG) in Berlin, postulating that energy is emitted in discrete packets — quanta — of size E=hν. This 'act of desperation,' as Planck called it, marks the birth of quantum theory. His constant h = 6.626×10⁻³⁴ J·s becomes a fundamental constant of nature.

  • T1 APS — Planck Radiation Formula Historical Note Official
  • T1 Nobel Prize Archive — Planck 1918 Lecture Official