Constants & Units · constant
Fine-structure constant
α = 7.297 352 5643(11) × 10⁻³ (1/137.035 999 177) —
- Unit
- —
- Value
- 7.297 352 5643(11) × 10⁻³ (1/137.035 999 177)
- Exact
- no
- Note
- Dimensionless, so every civilization measures the same number. Nobody knows why it is 1/137.
- Symbol
- α
- Category
- Electromagnetic
- Numeric
- 0.0072973525643
- Uncertainty
- ±1.6 × 10⁻¹⁰ relative
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