# Earth poles shifting **URL:** \ **Category:** Cecil's Columns/Staff Reports\ **Created:** [October 22, 1999, 8:02pm UTC](https://boards.straightdope.com/t/earth-poles-shifting/394 "1999-10-22T20:02:00Z")\ **Posts on this page:** 15\ **Page:** 2
**Author:** ![DrFidelius](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/drfidelius/32/3447_2.png) [@DrFidelius](https://boards.straightdope.com/u/DrFidelius)\ **Post date:** [October 28, 1999, 3:48pm UTC](https://boards.straightdope.com/t/earth-poles-shifting/394/21 "1999-10-28T15:48:00Z")
As “Rotate the shield nutation so the Romulans can’t adjust their phaser frequencies…” ---
**Author:** ![Polycarp](https://avatars.discourse-cdn.com/v4/letter/p/82dd89/32.png) [@Polycarp](https://boards.straightdope.com/u/Polycarp)\ **Post date:** [October 28, 1999, 3:59pm UTC](https://boards.straightdope.com/t/earth-poles-shifting/394/22 "1999-10-28T15:59:00Z")
I thought “nutation” was the phenomenon responsible for cloning trolls! 🙂 ---
**Author:** ![Triskadecamus](https://avatars.discourse-cdn.com/v4/letter/t/b19c9b/32.png) [@Triskadecamus](https://boards.straightdope.com/u/Triskadecamus)\ **Post date:** [October 28, 1999, 6:16pm UTC](https://boards.straightdope.com/t/earth-poles-shifting/394/23 "1999-10-28T18:16:00Z")
[New information on the phenomenon of magnetic pole shifts.](http://www.academicpress.com/inscight/10271999/grapha.htm) I don’t think you have to be member to access this site. If so, I apologize to the TM, each and all. Tris ---
**Author:** ![Akatsukami](https://avatars.discourse-cdn.com/v4/letter/a/ea666f/32.png) [@Akatsukami](https://boards.straightdope.com/u/Akatsukami)\ **Post date:** [October 28, 1999, 7:51pm UTC](https://boards.straightdope.com/t/earth-poles-shifting/394/24 "1999-10-28T19:51:00Z")
Konrad opines > [@](#): > > Why would we get cooked by a bunch of ions? Unless there is some sudden discharge like a lightning bolt ions are pretty harmless… Unless, of course, one accelerates them to within a few kps of lightspeed. Then, they are called “cosmic rays”. * * * “Kings die, and leave their crowns to their sons. Shmuel HaKatan took all the treasures in the world, and went away.” ---
**Author:** ![Konrad](https://avatars.discourse-cdn.com/v4/letter/k/f475e1/32.png) [@Konrad](https://boards.straightdope.com/u/Konrad)\ **Post date:** [October 28, 1999, 8:35pm UTC](https://boards.straightdope.com/t/earth-poles-shifting/394/25 "1999-10-28T20:35:00Z")
Akatsukami sez: > [@](#): > > Unless, of course, one accelerates them to within a few kps of lightspeed. Then, they are called “cosmic rays”. Cosmic rays are light. I guess that could happen if dem ions was travelling real fast and hit de atmosphere. But wouldn’t that light be reabsorbed by the atmosphere? Cosmic rays have really short wavelengths and the shorter the wavelength the more likely it is to be absorbed… ---
**Author:** ![Akatsukami](https://avatars.discourse-cdn.com/v4/letter/a/ea666f/32.png) [@Akatsukami](https://boards.straightdope.com/u/Akatsukami)\ **Post date:** [October 28, 1999, 9:19pm UTC](https://boards.straightdope.com/t/earth-poles-shifting/394/26 "1999-10-28T21:19:00Z")
Konrad opines: > [@](#): > > Cosmic rays are light. I respectfully disagree. See [http://www.umich.edu/~radinfo/](http://www.umich.edu/~radinfo/) . _Some_cosmic rays are photons with extremelt short wavelengths; as you say, though, they are quite effectively absorbed by the atmosphere. A large fraction, however, are ions (mostly hydrogen ions). Photons, being chargeless, penetrate magnetic fields with the same alarcity that they do lack of magnetic fields. Primary cosmics, OTOH, _are_ trapped in the Van Allen belts (the ionosphere is another phenomenon altogether). The problem, incidentally, is not so much with the ions themselves – “primary cosmics” – mere bags of water and other light elements such as ourselves being practically transparent to particles of that energy – but, when they hit the occasional heavier nucleus, they send showers of subatomic debris in all directions: “secondary cosmics”. * * * “Kings die, and leave their crowns to their sons. Shmuel HaKatan took all the treasures in the world, and went away.” ---
**Author:** ![RM\_Mentock](https://avatars.discourse-cdn.com/v4/letter/r/e274bd/32.png) [@RM\_Mentock](https://boards.straightdope.com/u/RM_Mentock)\ **Post date:** [November 10, 1999, 6:22am UTC](https://boards.straightdope.com/t/earth-poles-shifting/394/27 "1999-11-10T06:22:00Z")
I gotta disagree with the original poster, areynaldos. Cecil didn’t get it wrong. The poles do shift, not just the magnetic poles. John W. Kennedy: > [@](#): > > There are two “wobbles”. One, precession, is a longish cycle of 20-something thousand years. The other, nutation, is much smaller, and follows a cycle of only 19 years. There is also the [Chandler wobble](http://image.gsfc.nasa.gov/poetry/ask/a11435.html). This is a spiral motion of the instantanious rotation axis of the earth, with a period of about 14 months. > [@](#): > > None of this has to do with the hypothetical physical shift in the axis, which would, in our model, entail ripping the physical axis out of our globe and ramming it through from another angle. It’s just a continuous spiral. It doesn’t quite close back on itself, and there has been a decided drift over the last one hundred years: [Figure](http://hpiers.obspm.fr/webiers/general/earthor/polmot/figure1.html) > [@](#): > > That, for what it’s worth, is most definitely not happening “already”. The south-pole research station keeps very careful track of where the pole is, because the Antarctic ice shifts over it, and they have to move the marker every year, since it’s on the ice. But the pole itself is in the same place. (If it were shifting, every astronomer on Earth would see it immediately.) It is happening already. The astronomers discovered it over a hundred years ago. There is also a seasonal (12 month) forced wobble, and together their amplitude is less than arcsecond over the course of a year, but the amplitude varies: [Figure](http://hpiers.obspm.fr/webiers/general/earthor/polmot/figure2.html) ---
**Author:** ![RM\_Mentock](https://avatars.discourse-cdn.com/v4/letter/r/e274bd/32.png) [@RM\_Mentock](https://boards.straightdope.com/u/RM_Mentock)\ **Post date:** [November 10, 1999, 6:29am UTC](https://boards.straightdope.com/t/earth-poles-shifting/394/28 "1999-11-10T06:29:00Z")
Sorry. I tried to use the UBB url encoding from [http://www.straightdope.com/ubb/ubbcode.html](http://www.straightdope.com/ubb/ubbcode.html) and screwed it up. Here are the three URLs that were supposed to be included with my post: [http://image.gsfc.nasa.gov/poetry/ask/a11435.html](http://image.gsfc.nasa.gov/poetry/ask/a11435.html)[http://hpiers.obspm.fr/webiers/general/earthor/polmot/figure1.html](http://hpiers.obspm.fr/webiers/general/earthor/polmot/figure1.html)[http://hpiers.obspm.fr/webiers/general/earthor/polmot/figure2.html](http://hpiers.obspm.fr/webiers/general/earthor/polmot/figure2.html) Apologies. ---
**Author:** ![system](https://global.discourse-cdn.com/straightdope/original/2X/e/e489c3b7d8fce19c4b355dd4fc3f88cc39c34b87.png) [@system](https://boards.straightdope.com/u/system)\ **Post date:** [November 10, 1999, 3:04pm UTC](https://boards.straightdope.com/t/earth-poles-shifting/394/29 "1999-11-10T15:04:00Z")
Did the earth used to be “straight”? What cause the 23 degree tilt anyway? ---
**Author:** ![tomndebb](https://avatars.discourse-cdn.com/v4/letter/t/b9e5f3/32.png) [@tomndebb](https://boards.straightdope.com/u/tomndebb)\ **Post date:** [November 10, 1999, 3:49pm UTC](https://boards.straightdope.com/t/earth-poles-shifting/394/30 "1999-11-10T15:49:00Z")
When Gondwanaland broke up into our current six continents (seven if you’re Eurocentric), most of them headed north, leaving Antarctica as ballast. Unfortunately, South America had a thing for Africa and shifted east for companionship. With the abandonment of the Pacific basin, the northern continents were too heavy for Antarctica to counterbalance by itself and we tipped over. Fortunately, we were already spinning, so the gyroscopic effect kept us from falling over completely. We currently have a 22½° list. Engineers have been pondering the question of how to pump the Atlantic into the Pacific to trim the ballast and put us upright, again. They are being fought by a consortium of Vermont tourist agencies who fear that an untilted earth will result in a loss of seasons which would destroy their autumn-visitor-based economy. * * * Tom~ ---
**Author:** ![areynaldos](https://avatars.discourse-cdn.com/v4/letter/a/4bbf92/32.png) [@areynaldos](https://boards.straightdope.com/u/areynaldos)\ **Post date:** [November 10, 1999, 5:47pm UTC](https://boards.straightdope.com/t/earth-poles-shifting/394/31 "1999-11-10T17:47:00Z")
\> I gotta disagree with the original poster, \> areynaldos. Cecil didn’t get it wrong. \> The poles do shift, not just the \> magnetic poles. Ok, the magnetic poles do shift. But when you say that the Earth’s true poles also shift, what do you mean? That the Earth tilts and bounces in its plane of the orbit, or rather that its rotational axis through different points on the Earth? The first one I believe everyone is referring, and in this case, the true poles do not shift, the Earth always rotates around an axis that passes through the same places on Earth, although this axis crosses in different angles and positions the plane of the orbit. In the second case, it means the places where the rotational axis of the Earth crosses the surface are constantly changing… What would be (or are) the effects of this? ---
**Author:** ![RM\_Mentock](https://avatars.discourse-cdn.com/v4/letter/r/e274bd/32.png) [@RM\_Mentock](https://boards.straightdope.com/u/RM_Mentock)\ **Post date:** [November 11, 1999, 6:08am UTC](https://boards.straightdope.com/t/earth-poles-shifting/394/32 "1999-11-11T06:08:00Z")
I believe your first case is referring to precession. The rotation axis of the earth points to Polaris the north star, but it will point somewhere else in 10,000 years. The Chandler wobble is an instance of the second case, as the intantaneous rotation axis of the Earth is at different places at different times. One day it’s one place, the next day another. Its position moves in a circle over the course of about 14 months, although it is not a perfect circle. The diameter of this circle is less than one arcsecond, or about 1/60 of a nautical mile. Call it a hundred meters. Not all of this variance is due to the Chandler wobble, some of it is seasonal forcing, and the amplitude varies since the two effects beat against each other. UT1, corrected universal time, is UT0 corrected for the Chandler wobble. UT2 is corrected for seasonal effects. See the [sci.astro faq](http://www.landfield.com/faqs/astronomy/faq/part3/index.html). The Chandler wobble is one of the “holy grails” of geophysics. It is very intriguing, and not well explained. I’m certain its explanation will be attained in the next five years. ---
**Author:** ![RM\_Mentock](https://avatars.discourse-cdn.com/v4/letter/r/e274bd/32.png) [@RM\_Mentock](https://boards.straightdope.com/u/RM_Mentock)\ **Post date:** [December 8, 1999, 9:16am UTC](https://boards.straightdope.com/t/earth-poles-shifting/394/33 "1999-12-08T09:16:00Z")
I just wanted to say thanks to everyone who joined this thread. I’d been puzzling over the Chandler wobble for years, and not until I posted here did I think to ask Uncle Cecil about it. His answer, though still undefinitive, is here: [http://www.straightdope.com/columns/991203.html](http://www.straightdope.com/columns/991203.html) ---
**Author:** ![RobRoy](https://avatars.discourse-cdn.com/v4/letter/r/7ba0ec/32.png) [@RobRoy](https://boards.straightdope.com/u/RobRoy)\ **Post date:** [December 28, 1999, 3:48am UTC](https://boards.straightdope.com/t/earth-poles-shifting/394/34 "1999-12-28T03:48:00Z")
Two issues here, the actual poles (of rotation) wobbling and changing subtly over several cycles. The other, the magnetic poles changing is another. They have infact moved wildly over the globe in geologic history, but do have a relationship to the rotaional poles. The spinning of the earth creates a dynamo effect which in conjunction with the flow of magma under the crust tend to keep the magnetic poles oriented somewhat near the rotational poles. When the magnetic poles change they most frequently switch from north to south, and visa versa, although occassionally the magnetic north has been as far south as the equator. What’s the danger - someone above mentioned giant sparks…or something like that. Not too far off. We might be talking a major weather disturbance due to the magnetic pole’s role in regulating the ionosphere. Science is investigating this as either a result or precursor to major climate change. ---
**Author:** ![RM\_Mentock](https://avatars.discourse-cdn.com/v4/letter/r/e274bd/32.png) [@RM\_Mentock](https://boards.straightdope.com/u/RM_Mentock)\ **Post date:** [January 4, 2000, 5:35am UTC](https://boards.straightdope.com/t/earth-poles-shifting/394/35 "2000-01-04T05:35:00Z")
> [@](#): > > They have infact moved wildly over the globe in geologic history, but do have a relationship to the rotaional poles. The spinning of the earth creates a dynamo effect which in conjunction with the flow of magma under the crust tend to keep the magnetic poles oriented somewhat near the rotational poles. When the magnetic poles change they most frequently switch from north to south, and visa versa, although occassionally the magnetic north has been as far south as the equator. I don’t think that has been completely established. It’s a good guess, but the guess has been around for a long time, and no one has explained how such a process could work. . [Previous page](https://boards.straightdope.com/t/earth-poles-shifting/394.md?page=1)