scholarly journals Ancient Eclipses and the Earth’s Rotation

2002 ◽  
Vol 12 ◽  
pp. 338-341 ◽  
Author(s):  
L.V. Morrison ◽  
F.R. Stephenson

AbstractThe analysis of historical eclipses shows that the length of the day is increasing on the average by 1.8 milliseconds per century, as distinct from the value of 2.3 milliseconds per century expected from tidal friction. The difference may be accounted for by the response of the Earth to post-glacial uplift following the end of the last ice-age.

Occultations of stars by the Moon, and solar and lunar eclipses are analysed for variations in the Earth’s rotation over the past 2700 years. Although tidal braking provides the dominant, long-term torque, it is found that the rate of rotation does not decrease uniformly as would be expected if tidal friction were the only mechanism affecting the Earth’s rotation. There are also non-tidal changes present that vary on timescales ranging from decades to millennia. The magnitudinal and temporal behaviour of these non-tidal variations are evaluated in this paper.


1972 ◽  
Vol 48 ◽  
pp. 160-161
Author(s):  
R. R. Newton

The purpose of this work is to investigate changes in the rotation of the Earth in the past few thousand years. Since most available observations involve the Moon, study of the Earth's rotation is inseparable from study of the Moon's motion. Since it is doubtful that present theories of tidal friction account for the present acceleration (Spencer Jones, 1939; Van Flandern, 1970; Pariisky et al., 1972) of the Moon, we cannot safely assume that consequence of the theories which says that tidal friction has been almost constant.


The Bermuda Triangle is located in the area of the archipelago between North and South America and the Dragon Triangle is located in the area of the archipelago in Southeast Asia. There is a great resemblance between these two triangular areas; both were formed following special geological and tectonic conditions. It is herein proposed that their creation stems from the change in location of the axis of rotation of the earth and, accordingly, the change in the location of the equator.


1981 ◽  
Vol 39 (1-2) ◽  
pp. 157-158
Author(s):  
William M. Kaula

Author(s):  
L. V. Morrison ◽  
F. R. Stephenson ◽  
C. Y. Hohenkerk ◽  
M. Zawilski

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 −2 . These signify a mean accelerative component of +1.8 ± 0.1 × 10 −22  rad s −2 . There is also evidence of an oscillatory variation in the rate with a period of about 14 centuries.


1985 ◽  
Vol 19 (1) ◽  
pp. 193-205 ◽  
Author(s):  
Ya. S. Yatskiv ◽  
W. J. Klepczynski ◽  
F. Barlier ◽  
H. Enslin ◽  
C. Kakuta ◽  
...  

During the period, work on the problem of the Earth’s rotation has continued to expand and increase its scope. The total number of institutions engaged in the determination of the Earth’s rotation parameters (ERP) by different techniques has been increased significantly. The rotation of the Earth is currently measured by classical astrometry, Doppler and laser satellite tracking, laser ranging of the Moon, and radio interferometry. Several long time series of the ERP are available from most of these techniques, in particular, those made during the Main Campaign of the MERIT project. The various series have been intercompared and their stability, in the time frame of years to days, has been estimated for the purposes of establishing a new conventional terrestrial reference system (COTES). On the other hand, the difficulties of maintaining a regular operation for laser ranging to the Moon (LLR) have been recognized. It resulted in the proposal to organize an one-month campaign of observations in 1985 in order to complement the COTES collocation program and to allow additional intercomparisons with other techniques.


1979 ◽  
Vol 82 ◽  
pp. 7-18 ◽  
Author(s):  
Bernard Guinot

With the advent of more precise methods for measuring Earth rotation, a number of corrections to the apparent directions in space, to the terrestrial references, and to the rotation axis motion have to be carefully applied. It is the duty of the international Astronomical Union to give recommended or conventional expressions of these corrections in order to avoid inextricable difficulties in discussing the evaluated results. However, this task is not sufficient. The concepts used in the description of the Earth's rotation are somewhat obscured by traditions. They should be purified by removing notions which are not directly relevant.


1980 ◽  
Vol 78 ◽  
pp. 153-156
Author(s):  
T. V. Ruzmaikina

I wish to discuss an effect that is caused by the secular decrease in the Earth's rotation. I shall show that this deceleration induces mass flows across level surfaces and that these flows redistribute temperature and density in the Earth and produce an excess equatorial bulge. This mechanism does not require large lower mantle viscosity, unlike mechanisms discussed by Munk and MacDonald (1960) and McKenzie (1966). Therefore it does not suffer from the difficulties pointed out by Goldreich and Toomre (1969).


The following paper is an extension, to include the Earth’s rotation, of a discussion by J. Proudman and A. T. Doodson, treating of the corresponding phenomena in a non-rotating tidal channel. In the course of the solution it is necessary to have two functions expanded in two related series of special form (9), and a separate paper has been devoted to the expansion-theorem required.


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