# Addendum 2020 to ‘Measurement of the Earth’s rotation: 720 BC to AD 2015’

@article{Morrison2021Addendum2T, title={Addendum 2020 to ‘Measurement of the Earth’s rotation: 720 BC to AD 2015’}, author={L. Morrison and F. Stephenson and C. Hohenkerk and M. Zawilski}, journal={Proceedings of the Royal Society A}, year={2021}, volume={477} }

Historical reports of solar eclipses are added to our previous dataset (Stephenson et al. 2016 Proc. R. Soc. A 472, 20160404 (doi:10.1098/rspa.2016.0404)) in order to refine our determination of centennial and longer-term changes since 720 BC in the rate of rotation of the Earth. The revised observed deceleration is −4.59 ± 0.08 × 10−22 rad s−2. By comparison the predicted tidal deceleration based on the conservation of angular momentum in the Sun–Earth–Moon system is −6.39 ± 0.03 × 10−22 rad s… Expand

#### 3 Citations

Secular changes in length of day: Effect of the mass redistribution

- Physics
- 2021

In this paper the secular change in the length of day due to mass redistribution effects is revisited using the Hamiltonian formalism of the Earth rotation theories. The framework is a two-layer… Expand

Calculation of Moon Phases and 24 Solar Terms

- 2019

This document explains the method used to compute the times of the moon phases and 24 solar terms. These times are important in the calculation of the Chinese calendar. See this page for an… Expand

Hang on a second…

- Art
- 2021

Leslie Morrison and Catherine Hohenkerk consider the future direction of the leap second

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Secular tidal changes in lunar orbit and Earth rotation

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Small tidal forces in the Earth–Moon system cause detectable changes in the orbit. Tidal energy dissipation causes secular rates in the lunar mean motion n, semimajor axis a, and eccentricity e.… Expand

720 BC to AD 2015

- Proc. R. Soc. A 472, 20160404

Historical changes in UT/LOD from eclipses

- 2020