The units of time (both abs. time and duration) most practical to use when dealing with very long times, for example, in nuclear chem. and earth and planetary sciences, are multiples of the year, or annus (a). Its proposed definition in terms of the SI base unit for time, the second (s), for the epoch 2000.0 is 1 a = 3.1556925445 × 107 s. Adoption of this definition, and abandonment of the use of distinct units for time differences, will bring the earth and planetary sciences into compliance with quantity calculus for SI and non-SI units of time.
IUPAC-IUGS common definition and convention on the use of the year as a derived unit of time (IUPAC Recommendations 2011) / N.E. Holden, M. Bonardi, P. De Bievre, P.R. Renne, I.M. Villa. - In: PURE AND APPLIED CHEMISTRY. - ISSN 0033-4545. - 83:5(2011), pp. 1159-1162. [10.1351/PAC-REC-09-01-22]
IUPAC-IUGS common definition and convention on the use of the year as a derived unit of time (IUPAC Recommendations 2011)
M. BonardiSecondo
;
2011
Abstract
The units of time (both abs. time and duration) most practical to use when dealing with very long times, for example, in nuclear chem. and earth and planetary sciences, are multiples of the year, or annus (a). Its proposed definition in terms of the SI base unit for time, the second (s), for the epoch 2000.0 is 1 a = 3.1556925445 × 107 s. Adoption of this definition, and abandonment of the use of distinct units for time differences, will bring the earth and planetary sciences into compliance with quantity calculus for SI and non-SI units of time.
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