Variations in the Earth’s rotation rate measured with a ring laser interferometer

K. Ulrich Schreiber, Jan Kodet, Urs Hugentobler, Thomas Klügel, Jon Paul R. Wells

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


An exact knowledge of the instantaneous Earth’s rotation rate is indispensable for accurate navigation and geolocation. Fluctuations in the length of sidereal day are caused by momentum exchange between the fluids of the Earth (namely, the atmosphere, hydrosphere and cryosphere) and the solid Earth. Since a multitude of different globally distributed and independent mass transport phenomena are involved, the resultant effect on the Earth’s rotation is not predictable and needs to be continuously measured. Here we report the observation of minute variations in the rotation rate of the Earth at the level of five parts per billion, namely, with a resolution of a few milliseconds over 120 days of continuous measurements. We employ an inertial self-contained measurement technique based on an optical ring laser interferometer rigidly strapped down to the Earth’s crust and operated in the Sagnac configuration. This large-scale gyroscope integrates over three hours for each data point, as opposed to an entire global network of Global Navigation Satellite Systems receivers and Very Long Baseline Interferometry that can only provide a single measurement per day.

Original languageEnglish
Pages (from-to)1054-1058
Number of pages5
JournalNature Photonics
Issue number12
StatePublished - Dec 2023


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