Quantum theory begins
Planck finds that energy comes in packets, and reluctantly means it.
- When
- —
- Duration
- 13 years
- Known to
- ± 1 year
- Era
- Industrial, Holocene
Planck solves the black-body radiation problem in 1900 by assuming energy is emitted in discrete quanta, a step he described as an act of desperation and hoped to eliminate later. Einstein takes it literally in 1905 to explain the photoelectric effect — the work for which he received the Nobel Prize, not relativity. Bohr applies it to atomic structure in 1913. Classical physics is broken and nobody yet knows what replaces it.