Provisional Recommendations
Provisional Recommendations
www.iupac.org/reports/provisional
Convention on the Use of Units for Time in Earth and Planetary Sciences
The units of time (both absolute time and duration) most practical to use in Earth and Planetary Sciences are multiples of the year, or annus (a). Its proposed definition in terms of the fundamental SI unit for time, the second (s), for the epoch 2000.0 is 1 a = 3.1556925445 x 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 the SI standard regarding units of time.
Comments by 30 June 2009
To Dr. Igor Villa
Institut für Geologie
Universität Bern
CH-3012 Bern, Switzerland
E-mail: igor@geo.unibe.ch
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Articles in the same Issue
- Masthead
- From the Editor
- Contents
- Chemistry Solutions
- Amount of Substance and the Mole
- Customs, Chemistry, and IUPAC: An Old Story
- What’s in a Chemical Name?
- Helping Improve Biosafety and Biosecurity: IUPAC’s Contribution to the Biological and Toxin Weapons Convention
- UN Declares 2011 as International Year of Chemistry
- IUPAC Executive Director Search
- Val Metanomski Remembered*
- In Memoriam
- Guide for Authors of Papers and Reports in Polymer Science and Technology
- Update of Glossary of Terms Used in Medicinal Chemistry
- Analogue-based Drug Discovery II
- Frontiers of Chemical Sciences: Research and Education in the Middle East
- Investigating Out-of-Specification Test Results of Chemical Composition Based on Metrological Concepts
- Young Ambassadors for Chemistry in Taipei, Taiwan, and Mauritius
- Provisional Recommendations
- Functional Food and Health
- Biodiversity and Chemistry of Natural Products
- Vanadium
- Chemical Nomenclature and Structure Representation
- Vacuum Microbalance and Thermoanalytical Techniques
- Space Research
- Mediators of Science: Women Translators
- Heterocyclic Chemistry
- Mark Your Calendar
