Other pages in this series (31)
Display constant
c · speed of light in vacuum
진공에서의 빛의 속력
Takeaway
- The relative standard uncertainty fell by a factor of about 83 from the 1969 to the 1973 edition (3.3×10⁻⁷ → 4.0×10⁻⁹): the error bars narrowed that much.
- Both earlier editions with a measured value contain the 2022 value within ±1σ (the error bar). The 2022 value is exact.
- The largest move between editions came in 1969→1973, at 0.4 times the combined standard uncertainty of the two editions (|z| = 0.4).
- Exact from the 1986 edition (fixed by definition rather than measured), so its uncertainty is zero.
- Unit
- m s⁻¹
- Note
- The meter was redefined in 1983; exact from the 1986 edition. Measured in the 1969 and 1973 editions.
- M1
- —
Value ±1σ by edition2022
| Editionyear of the recommended values (data cut-off) | As printedexactly as in the source table; digits in parentheses are the standard uncertainty in the last digits | Standard uncertaintyhalf-width of the error bar (±1σ) | Relative standard uncertaintystandard uncertainty ÷ |value|: bar width relative to the value | Exactfixed by definition, uncertainty zero | z vs previous editionmove from the previous edition ÷ combined standard uncertainty of the two | z vs 2022(2022 value − this value) ÷ this edition's standard uncertainty | Source locationpage and table of the paper, or file and line of NIST's table |
|---|---|---|---|---|---|---|---|
| 1969 | 2.9979250(10) e8 | 1.0×10² | 3.3×10⁻⁷ | −0.4200 | 477 table XXXII | ||
| 1973 | 299792458(1.2) | 1.2×10⁰ | 4.0×10⁻⁹ | −0.4200 | 0.0000 | 717 table 33.1 | |
| 1986 | 299792458 | yes | codata86 p.8 table 2 | ||||
| 1998 | 299 792 458 | yes | 1998 ASCII:294 | ||||
| 2002 | 299 792 458 | yes | 2002 ASCII:298 | ||||
| 2006 | 299 792 458 | yes | 2006 ASCII:300 | ||||
| 2010 | 299 792 458 | yes | 2010 ASCII:313 | ||||
| 2014 | 299 792 458 | yes | 2014 ASCII:313 | ||||
| 2018 | 299 792 458 | yes | 2018 ASCII:329 | ||||
| 2022 | 299 792 458 | yes | 2022 ASCII:330 |