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The information in this table has not been updated since 1965. A better source to check for more current information is:
The Cambridge University Press Handbook of Space Astronomy and Astrophysics

Table VIII. - Defined Values and Equivalents (Recommended by NAS-NRC, 1963)

Unit Abbreviation Value
Meter m 1,650,763.73 wavelengths in vacuo of the unperturbed transition 2p10-5d5 in Kr86
Kilogram kg mass of the international kilogram at Sevres, France
Second s 1/31,556,925.9747 of the tropical year at 12h ET, 0 January 1900
Degree Kelvin °K defined in the thermodynamic scale by assigning 273.16 °K to the triple point of water (freezing point, 273.15 °K = 0 °C)
Unified atomic mass unit u 1/12 the mass of an atom of the C12 nuclide
Mole mol amount of substance containing the same number of atoms as 12g of pure C12
Standard acceleraaation of free fall gn 9.80665 m a-2
Normal atmospheric pressure atm 101325 N m-2, 980.665 cm s-2
Thermochemical calorie calth 4.1840 J, 4.1840 X 107 erg
International Steam Table calorie cal, T 4.1868 J, 4.1868 X 107 erg
Liter l 0.001000028 m3, 1000.028 cm3 (recommended by CIPM, 1950)
Inch in. 0.0254 m, 2.54 cm
Pound (avdp.) lb 0.45359237 kg, 453.59237 g

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