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Type: Journal article
Title: Colloquium: Comparison of astrophysical and terrestrial frequency standards
Author: Hartnett, J.
Luiten, A.
Citation: Reviews of Modern Physics, 2011; 83(1):1-9
Publisher: American Physical Society
Issue Date: 2011
ISSN: 0034-6861
Statement of
John G. Hartnett and Andre N. Luiten
Abstract: The stability of pulse arrival times from pulsars and white dwarfs have been reanalyzed using several analysis tools for measuring the noise characteristics of sampled time and frequency data. The best terrestrial artificial clocks are shown to substantially exceed the performance of astronomical sources as timekeepers in terms of accuracy (as defined by cesium primary frequency standards) and stability. This superiority in stability can be directly demonstrated over time periods up to 2 years, where there is high quality data for both. Beyond 2 years there is a deficiency of data for clock-to-clock comparisons, and both terrestrial and astronomical clocks show equal performance being equally limited by the quality of the reference time scales used to make the comparisons. Nonetheless, the detailed accuracy evaluations of modern terrestrial clocks imply that these new clocks are likely to have a stability better than any astronomical source up to comparison times of at least hundreds of years. This article is intended to provide a correct appreciation of the relative merits of natural and artificial clocks. The use of natural clocks as tests of physics under the most extreme conditions is entirely appropriate; however, the contention that these natural clocks, particularly white dwarfs, can compete as timekeepers against devices constructed by mankind is shown to be doubtful.
Rights: © 2011 The American Physical Society
RMID: 0020130732
DOI: 10.1103/RevModPhys.83.1
Appears in Collections:IPAS publications

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