The Irregular Variation in the Speed of Rotation of the Earth
In attempting to determine the past and future of the dynamics of the Earth-Moon system, one element of importance is the nature of the irregular variation in the speed of rotation of the Earth. Formerly, it was customary to represent the observations by abrupt changes in the speed of rotation of the Earth. One therefore represented ΔT = E. T. − U. T. (Ephemeris Time—Universal Time) by segments of straight lines. Brouwer (1952) represented ΔT, as determined from observations of the Moon, by segments of parabolas with common tangents at the junctions.
KeywordsSecular Variation Polar Motion Universal Time Monthly Means Atomic Clock
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