Precession of the Earth's axis
In astronomy, axial precession is a gravity-induced, slow, and continuous change in the orientation of an astronomical body's rotational axis. In particular, it refers to the gradual shift in the orientation of Earth's axis of rotation, which, similar to a wobbling top, traces out a pair of cones joined at their apices in a cycle of approximately 26,000 years (called a Great or Platonic Year in astrology). The term "precession" typically refers only to this largest secular motion; other changes in the alignment of Earth's axis – nutation and polar motion – are much smaller in magnitude.
Earth's precession was historically called the precession of the equinoxes, because the equinoxes moved westward along the ecliptic relative to the fixed stars, opposite to the motion of the Sun along the ecliptic. This term is still used in non-technical discussions, that is, when detailed mathematics are absent. Historically,Hipparchus has been credited with discovering precession of the equinoxes, although evidence from cuneiform tablets suggest that his statements and mathematics relied heavily on Babylonian astronomical materials that had existed for many centuries prior. The exact dates of his life are not known, but astronomical observations attributed to him by Ptolemy date from 147 BC to 127 BC.
With improvements in the ability to calculate the gravitational force between and among planets during the first half of the nineteenth century, it was recognized that the ecliptic itself moved slightly, which was named planetary precession, as early as 1863, while the dominant component was named lunisolar precession. Their combination was named general precession, instead of precession of the equinoxes.
Lunisolar precession is caused by the gravitational forces of the Moon and Sun on Earth's equatorial bulge, causing Earth's axis to move with respect to inertial space. Planetary precession (an advance) is due to the small angle between the gravitational force of the other planets on Earth and its orbital plane (the ecliptic), causing the plane of the ecliptic to shift slightly relative to inertial space. Lunisolar precession is about 500 times greater than planetary precession. In addition to the Moon and Sun, the other planets also cause a small movement of Earth's axis in inertial space, making the contrast in the terms lunisolar versus planetary misleading, so in 2006 the International Astronomical Union recommended that the dominant component be renamed, the precession of the equator, and the minor component be renamed, precession of the ecliptic, but their combination is still named general precession. Many references to the old terms exist in publications predating the change.

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Precession of the Earth's Rotation Axis
The Earth's rotation axis is not fixed in space. Like a rotating toy top, the direction of the rotation axis executes a slow precession with a period of 26,000 years ...
csep10.phys.utk.edu/astr161/lect/time/precession.html
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Astronomy: precession of earth - Astro Wsu
Sep 12, 2000 ... They also cause an oscillation in the ellipticity of earth's orbit. Taken in conjunction with the 26000-year spin-axis precession, the 71000-year ...
astro.wsu.edu/worthey/astro/html/lec-precession.html
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Axial precession - Wikipedia, the free encyclopedia
The Precession of the Earth's axis has a number of observable effects. First, the positions of the south and north celestial poles appear to move in circles against ...
en.wikipedia.org/wiki/Axial_precession
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Precession - Wikipedia, the free encyclopedia
For example, the earth is subject to local torque induced precession due to the gravity of the sun and moon acting upon the earth's axis, but at the same time the ...
en.wikipedia.org/wiki/Precession
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Precession of the Earth's Axis
The Earth's axis rotates (precesses) just as a spinning top does. The period of precession is about 26,000 years. Therefore, the North Celestial Pole will not ...
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Precession of the Earth's Spin Axis
In the presence of external torque, the spinning object will precess . Observations indicate that the Earth's spin axis is precessing with a period of about 26,000 ...
hyperphysics.phy-astr.gsu.edu/hbase/solar/earthprecess.html
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The Precession of the Earth's Axis In this document I will elucidate ...
In this document I will elucidate why the Earth's rotation axis precesses, and also show how complex physical phenomena can often be estimated without titanic ...
courses.physics.northwestern.edu/Phyx125/Precession%20of%20the%20Earth.pdf
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Precession of the Earth's Axis - Tripod
One would think NASA would have a good handle on astronomical movements. After all, they did get a man on the moon, satellites to orbit and robots to rove on ...
fuliginouspalaver.tripod.com/comingtolight/id16.html
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precession - definition of precession by the Free Online Dictionary ...
Astronomy. a. Precession of the equinoxes. b. A slow gyration of the earth's axis around the pole of the ecliptic, caused mainly by the gravitational pull of the sun, ...
www.thefreedictionary.com/precession
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Axial precession - Wikipedia, the free…
In astronomy, axial precession is a gravity-induced, slow, and continuous change in the orientation of an astronomical body's rotational axis. In particular, it ...
en.wikipedia.org/wiki/Axial_precession_(astronomy)
Search results for "Precession of the Earth's axis"
Precession of the Earth's axis in science
Precession of the Earth's Rotation Axis
The Earth's rotation axis is not fixed in space. Like a rotating toy top, the direction of the rotation axis executes a slow precession with a period of 26,000 years ...
Axial precession - Wikipedia, the free encyclopedia
For precession of the axes outside of astronomy, see Precession. .... The Precession of the Earth's axis has a number of observable effects. First, the ...... a b c Astro 101 – Precession of the Equinox, Western Washington University Planetarium, ...
Precession of the Earth's Axis
The Earth's axis rotates (precesses) just as a spinning top does. The period of precession is about 26,000 years. Therefore, the North Celestial Pole will not ...
CHAPTER XXIV - THE PRECESSION AND NUTATION OF THE ...
Cambridge University Press. Utility. University Publishing Online ... The Story of the Heavens; THE PRECESSION AND NUTATION OF THE EARTH'S AXIS pp.
Earth's Rotation
Earth rotates around its axis (in a counter-clockwise direction, when viewed ... " Wobbling" of Earth's Axis of Rotation (Axial Nutation and Axial Precession).
Activity for Precession of the Equinoxes - Center for Science Education
©1995 The Regents of the University of California ... The Earth's rotation on its axis has caused the Earth's shape to diverge from a sphere, and has ... The Earth's precession implies that although Polaris is currently the star above our North ...
Precession - Science Daily
Precession refers to a change in the direction of the axis of a rotating object. In certain contexts, "precession" may refer to the precession that the Earth experiences, ... Other Planets Influence Earth's Climate, University Of Toronto Scientist Says ...
How do we know Earth's precession period is 26,000 years?
We can see easily the movement of polaris with respect to the polar axis, since earth angular moment is a constant, ... Ulrich Mutze · Ludwig-Maximilian-University of Munich ... Actually precession describes the angular motion of Earth's body.
Precession
V. PRECESSION. Due to the interaction between the Earth and the Moon, the rotation axis of the Earth is not stationary. The interaction arises because the Moon ...
Books on the term Precession of the Earth's axis
Earth's Climate: Past and Future
William F. Ruddiman, 2008
Earth wobbles very slowly; it revolves 25,700 times around the Sun and rotates almost 10 million times on its axis during the time it takes to complete just a single wobble. A second kind of precessional motion is known as precession of the ...
An Introduction to Physical Science, 13th ed.
James T. Shipman, Jerry D. Wilson, Aaron Todd, 2012
FIGURE 15.18 Precession of the Earth's axis Right: The Earth's axis is presently pointing toward the star Polaris, which we call the pole star or North Star. Left: In approximately 12,000 years, the axis will again be pointing toward the star Vega  ...
Practical Astronomy: A User-Friendly Handbook for Skywatchers
Henry Robert Mills, 1994
5.6 THE Precession of the Earth's axis In Section 1.6 the spinning of the Earth was likened to a spinning top which although it spins steadily, nevertheless under various external forces its axis wobbles or to use the technical term, ...
Energy Demand and Climate Change: Issues and Resolutions
Simultaneously, over a period of 41,000 years, this tilt angle cycles slowly between 21.1 and 24.5 degrees. Because of precession, Earth's rotation axis points over time to different portions of the sky. The swinging-around action of the Earth's ...

Blog posts on the term
Precession of the Earth's axis
[WATCH]: Precession of Earth's Axis [3DCG Animation+Music] | Music
Posted on July 5, 2013 by JinHsiang Mo.
music.jhmblog.com/2013/07/05/watch-precession-of-earths-axis-3dcg-animationmusic/
You Are The Guru: Christianity or Worship of the Sun God
I wrote this a while ago now, it is basically a summation and re-telling of some of the information from the first part of the 2007 documentary movie Zeitgeist, made by Peter Joseph. If you haven't seen it go to you tube and watch it now for free.
hidden-guru.blogspot.com/2013/07/christianity-or-worship-of-sun-god.html
The Earth’s Wobble – Precession | My Dark Sky
Lifelong companion under the stars
mydarksky.org/2008/10/14/the-earths-wobble-precession/
Earth’s Climate at the Age of the Dinosaurs | Mathematics of Planet Earth 2013
Is it possible to compute the past climate of the Earth at the time of dinosaurs? This question was answered by Jacques Laskar during his lecture entitled “Astronomical calibration of the Geological Time Scales” at the workshop “Mathematical models and methods for Planet Earth” at Istituto Nazionale di Alta Matematica (INdAM) on May 27-29. Laskar explained that Louis-Joseph Lagrange was the first to suggest a link between the past climates of the Earth and the variations of the parameters characterizing the Earth’s elliptical orbit: the latter concern the changes in the major axis, in the eccentricity, in the obliquity of the Earth’s axis, and in the precession of the Earth’s axis.
mpe2013.org/2013/06/05/earths-climate-at-the-age-of-the-dinosaurs/
Trivia » It takes roughly how long for the Earth’s rotating axis to complete a full circle (precession): 26,000 years; 365 days; 30 days; or one day?
26,000 years (the turning axis is better understood by imagining a spinning top as it slows down and rotates around a changing axis, rather than a fixed axis – the angle of the Earth’s axis is currently around 23. 4 degrees – this varies too, on a 41,000 year cycle).
trivia.igeek.net.au/?p=10128
As the World Turns | Bob's Spaces
Earth and Space Sciences Education (by Bob Riddle)
bobs-spaces.net/2013/01/19/as-the-world-turns/
The Herd Boy and the Weaving Girl | One-Minute Astronomer
The ancient star legends from cultures all over the world still capture our attention and connect us with the long line of humanity passed, those who gazed upon
www.oneminuteastronomer.com/8786/herd-boy-weaving-girl/
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