This article is about motion relative to the crust. For motion relative to an astronomical framework, see axial precession and astronomical nutation.
Motion of Earth's rotational axis relative to its crust
Polar motion in arc-seconds as function of time in days (0.1 arcsec ≈ 3 meters).[1]
Polar motion of the Earth is the motion of the Earth's rotational axis relative to its crust.[2]: 1 This is measured with respect to a reference frame in which the solid Earth is fixed (a so-called Earth-centered, Earth-fixed or ECEF reference frame). This variation is a few meters on the surface of the Earth.
^Folgueira, M. (2005). "Free polar motion of a triaxial and elastic body in Hamiltonian formalism: Application to the Earth and Mars" (PDF). Astron. Astrophys. 432 (3): 1101–1113. Bibcode:2005A&A...432.1101F. doi:10.1051/0004-6361:20041312.
^Lambeck, Kurt (2005). The earth's variable rotation : geophysical causes and consequences (Digitally printed ed.). Cambridge: Cambridge University Press. ISBN 978-0521673303.
Polarmotion of the Earth is the motion of the Earth's rotational axis relative to its crust.: 1 This is measured with respect to a reference frame in...
introduction of the polar system was the study of circular and orbital motion. Polar coordinates are most appropriate in any context where the phenomenon...
also induce small changes. These subjects are covered in the article Polarmotion. The mass distribution of the Earth is not spherically symmetric, and...
Geodetic Association in 1899 to study variations in latitude caused by polarmotion, precession, or "wobble" of the Earth's axis. In 1891, at the meeting...
circumplanetary systems. Geodynamical phenomena, including crustal motion, tides, and polarmotion, can be studied by designing global and national control networks...
refers only to this largest part of the motion; other changes in the alignment of Earth's axis—nutation and polarmotion—are much smaller in magnitude. Earth's...
Polar wander is the motion of a pole in relation to some reference frame. It can be used, for example, to measure the degree to which Earth's magnetic...
Measurement of geodynamical phenomena, such as crustal dynamics and polarmotion: 4 : 1 Satellite geodetic data and methods can be applied to diverse...
(UT as formerly computed), UT1 (UT0 corrected for polarmotion) and UT2 (UT0 corrected for polarmotion and seasonal variation). UT1 was the version sufficient...
decades. There is another disturbance of the Earth's rotation called polarmotion that can be estimated for only a few months into the future because it...
years, so that the total polarmotion varies with a period of about 7 years. The Chandler wobble is an example of the kind of motion that can occur for a...
of the Moon in the sky, the relative motion of Earth and the Moon, Earth's rotation, lunar libration, polarmotion, weather, speed of light in various...
poles to shift slightly over cycles of varying lengths (see nutation, polarmotion and axial tilt). Finally, over very long periods the positions of the...
consequently the zenith measurements contained significant systematic errors. Polarmotion predicted by Leonard Euler and later discovered by Seth Carlo Chandler...
Hilton, James L; McCarthy, Dennis D. (2013). "Precession, Nutation, PolarMotion, and Earth Rotation". In Sean Urban; P. Kenneth Seidelmann (eds.). Explanatory...
related to Geographical poles. Earth's rotation Polarmotion Poles of astronomical bodies True polar wander Kotlyakov, Vladimir; Komarova, Anna (2006)...
including the daily and sub-daily polarmotion, and length-of-day variabilities, Earth's center-of-mass - geocenter motion, and low-degree gravity field parameters...
Midnight sun, also known as polar day, is a natural phenomenon that occurs in the summer months in places north of the Arctic Circle or south of the Antarctic...
described as î and j, the motion is best described in polar form with components that resemble polar vectors. As with planar motion, the velocity is always...
the conservation of angular momentum. Axial tilt Polarmotion Rotation around a fixed axis True polar wander Kumar, B.; DeRemer, D.; Marshall, D. (2005)...
The positions of the Tropical and Polar Circles are not fixed because the axial tilt changes slowly – a complex motion determined by the superimposition...
and pulls out a can of Polar Seltzer and drinks from it contentedly. Coca-Cola filed a motion for an injunction against Polar in United States District...
Union of Geodesy and Geophysics, replacing the earlier International PolarMotion Service (IPMS) and the Earth rotation section of the Bureau International...
research on what is today known as the Chandler wobble. His research on polarmotion spanned nearly three decades. Chandler also made contributions to other...
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