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The Chandler Wobble
First in browsing the astronomy groups I came upon sci.astronomy only to find it is no longer in use. Or is it just Google no longer posting to it? How come it went out of fashion, anyone know? And now to business: I was trying to find out more about the Chandler Wobble on here "only to find" no one has mentioned it in several years. May I take you are all as much in the dark about it as I am? |
#2
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The Chandler Wobble
"Weatherlawyer" wrote in message oups.com... First in browsing the astronomy groups I came upon sci.astronomy only to find it is no longer in use. Or is it just Google no longer posting to it? How come it went out of fashion, anyone know? And now to business: I was trying to find out more about the Chandler Wobble on here "only to find" no one has mentioned it in several years. May I take you are all as much in the dark about it as I am? --- Very interesting topic, Weatherlawyer. For those unfamiliar: the Chandler Wobble is a phenomenon discovered by American astronomer Seth Chandler before the turn of the century. It describes a small irregularity in the Earth's rotation whereby the Earth's axis 'wobbles' slightly, a bit like that of a spinning top slowing down. Rather than spinning at a point, the north pole effectively moves in little spirals of increasing or decreasing size, of a few metres diameter. The magnitude of the wobble varies, almost stopping at times and becoming more extreme at others. The Jet Propulsion Lab's Dr Gross issued a statement some 15 years ago that he believed it was all due to varying pressures at the bottom of the oceans, caused by changing temperatures, winds and salinity and resultant currents, etc. ... all very complicated. More interesting still is the (unproven) theory that volcanic and seismic activity is linked to the 6.5 year average cycle of the wobble's maxima and minima. There is certainly some statistical evidence to suggest that there is a degree of harmonic regularity to volcanic outbursts and earth/sea quakes and one may even derive a cyclic period from bunches of peaks on the graphs, but there is no clear synchronicity with our friendly wobble, even allowing for lags due to the huge mass of the earth. References: http://www.abc.net.au/science/news/e...ish_153343.htm http://www.michaelmandeville.com/pol...relations2.htm |
#3
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The Chandler Wobble
TeaTime wrote: "Weatherlawyer" wrote in message oups.com... First in browsing the astronomy groups I came upon sci.astronomy only to find it is no longer in use. Or is it just Google no longer posting to it? How come it went out of fashion, anyone know? And now to business: I was trying to find out more about the Chandler Wobble on here "only to find" no one has mentioned it in several years. May I take you are all as much in the dark about it as I am? --- Very interesting topic, Weatherlawyer. For those unfamiliar: the Chandler Wobble is a phenomenon discovered by American astronomer Why so modest? USAan astronomer Seth Chandler before the turn of the century. It describes a small irregularity in the Earth's rotation whereby the Earth's axis 'wobbles' slightly, a bit like that of a spinning top slowing down. What is this thing with child's tops? When was the lst time anyone saw one of them? Is the analogy about the top of the toy or the pointy end? Does the pointy end move or wobble? I can't remember. Rather than spinning at a point, the north pole effectively moves in little spirals of increasing or decreasing size, of a few metres diameter. The magnitude of the wobble varies, almost stopping at times and becoming more extreme at others. Almost stopping as in reaching a "point of dwell" as might be imagined with the declination of the moon or sun? And observed in reciprocating engines at top and bottom dead centres under a stroboscope. Or almost stopping as in: ""Sun, be motionless over GibŽe·on, And, moon, over the low plain of AiŽja·lon." Accordingly the sun kept motionless, and the moon did stand still" ? The Jet Propulsion Lab's Dr Gross issued a statement some 15 years ago that he believed it was all due to varying pressures at the bottom of the oceans, caused by changing temperatures, winds and salinity and resultant currents, etc. ... all very complicated. And a lot less likely than the unbelievable idea that the moon has the power to raise enough miniscule particles of water to raise a tide, without having the same ability to raise it all the way to the moon. More interesting still is the (unproven) theory that volcanic and seismic activity is linked to the 6.5 year average cycle of the wobble's maxima and minima. There is certainly some statistical evidence to suggest that there is a degree of harmonic regularity to volcanic outbursts and earth/sea quakes and one may even derive a cyclic period from bunches of peaks on the graphs, but there is no clear synchronicity with our friendly wobble, even allowing for lags due to the huge mass of the earth. The list of unproven theories like that is longer than you might be expected to believe since no one has really looked at the subject as far as I know. Give us endless articles about life on Mars and you can spend as much time and money developing rockets and satellites and etc... I wonder what the infrastructure for something like that would cost, compared to something a lot more useful and even more mundane. References: http://www.abc.net.au/science/news/e...ish_153343.htm http://www.michaelmandeville.com/pol...relations2.htm Hey, I followed those two Google links too. I also looked at the http://hpiers.obspm.fr/ site Euhau, euhau, euhau! Zose sheez ateuing Fronjemane; zey are not zo zurrendeure monkayz etr? Non? |
#4
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The Chandler Wobble
"Weatherlawyer" wrote in message oups.com... Why so modest? You've lost me there I'm afraid. Who is being modest and in what context? What is this thing with child's tops? When was the lst time anyone saw one of them? I believe a spinning top is an understandable analogy in trying to explain the motions involved. I think the majority of people have seen one, at least on television or whatever. Is the analogy about the top of the toy or the pointy end? Does the pointy end move or wobble? I can't remember. In the case of a top, it is the top end that precesses about. In the cae of the earth it is both poles, with the precessionary centre somewhere between and shifting. Almost stopping as in reaching a "point of dwell" as might be imagined with the declination of the moon or sun? And observed in reciprocating engines at top and bottom dead centres under a stroboscope. Or almost stopping as in: ""Sun, be motionless over GibŽe·on, And, moon, over the low plain of AiŽja·lon." Accordingly the sun kept motionless, and the moon did stand still" ? Almost stopping as in a period of more than 2 months out of the 14 month cycle (as seen at the beginning of this year infact). Apparently irregular and reasons unknown. And a lot less likely than the unbelievable idea that the moon has the power to raise enough miniscule particles of water to raise a tide, without having the same ability to raise it all the way to the moon. I think the math is fairly straightfoward - escape velocity would come into play if we wanted to consider leeching at the level you describe. Binary star systems can do it, but they have very much higher gravities than our puny litle system. The list of unproven theories like that is longer than you might be expected to believe since no one has really looked at the subject as far as I know. I think you will find that a great many experts have pondered this anomaly and continue to do so. Give us endless articles about life on Mars and you can spend as much time and money developing rockets and satellites and etc... I wonder what the infrastructure for something like that would cost, compared to something a lot more useful and even more mundane. I think that may be what is considered to be the advancement of science via the exploration of space. If we ran a poll, I'm sure we'd find thousands of preferences of how such funds might be best used. I also looked at the http://hpiers.obspm.fr/ site Yes, a concise disaply of recent meanderings. The IERS provides a good source of facts and figures on this topic. Euhau, euhau, euhau! Zose sheez ateuing Fronjemane; zey are not zo zurrendeure monkayz etr? Non? I'll have a large glass of whatever you're on, my friend. Cheers! |
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The Chandler Wobble
The Jet Propulsion Lab's Dr Gross issued a statement some 15 years ago that
he believed it was all due to varying pressures at the bottom of the oceans, caused by changing temperatures, winds and salinity and resultant currents, etc. ... all very complicated Well there a thought, what happens when the temperatures, winds and the salinity of the sea are affected by global warming. Where's the wobble going to go then east, west or very erratic? "TeaTime" wrote in message ... "Weatherlawyer" wrote in message oups.com... First in browsing the astronomy groups I came upon sci.astronomy only to find it is no longer in use. Or is it just Google no longer posting to it? How come it went out of fashion, anyone know? And now to business: I was trying to find out more about the Chandler Wobble on here "only to find" no one has mentioned it in several years. May I take you are all as much in the dark about it as I am? --- Very interesting topic, Weatherlawyer. For those unfamiliar: the Chandler Wobble is a phenomenon discovered by American astronomer Seth Chandler before the turn of the century. It describes a small irregularity in the Earth's rotation whereby the Earth's axis 'wobbles' slightly, a bit like that of a spinning top slowing down. Rather than spinning at a point, the north pole effectively moves in little spirals of increasing or decreasing size, of a few metres diameter. The magnitude of the wobble varies, almost stopping at times and becoming more extreme at others. The Jet Propulsion Lab's Dr Gross issued a statement some 15 years ago that he believed it was all due to varying pressures at the bottom of the oceans, caused by changing temperatures, winds and salinity and resultant currents, etc. ... all very complicated. More interesting still is the (unproven) theory that volcanic and seismic activity is linked to the 6.5 year average cycle of the wobble's maxima and minima. There is certainly some statistical evidence to suggest that there is a degree of harmonic regularity to volcanic outbursts and earth/sea quakes and one may even derive a cyclic period from bunches of peaks on the graphs, but there is no clear synchronicity with our friendly wobble, even allowing for lags due to the huge mass of the earth. References: http://www.abc.net.au/science/news/e...ish_153343.htm http://www.michaelmandeville.com/pol...relations2.htm |
#6
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The Chandler Wobble
Weatherlawyer wrote
May I take you are all as much in the dark about it as I am? You may not. Get thee to a library, or consult with Prof. Michael Chinnery of Brown University, Rhode Island, who wrote a brief analysis of the Chandler wobble and it's possible causes many years ago for the Open University course book 'Understanding the Earth' published by Artemis press. A further source is 'The rotation of the Earth', W H Munk & G J F MacDonald, 1960, Cambridge University press. I am aware that these refs are somewhat old but they come from a period when my interests were less focussed. :-) Denis -- DT change nospam: n o s p a m v a l l e ys |
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