Earthling Posted May 13, 2011 Posted May 13, 2011 I don't believe any laws of physics must be revised: Briefly, the GTME (Gravity Theory of Mass Extinction) posits the following: 1. Today, the Earth's continental land masses are disributed fairly uniformly around the globe. In the distant past (e.g., when Pangea existed) the distribution did not have this uniformity. When there is a change in continental distribution, several things happen concurrently: a. A wobble of the Earth will occur. b. Nutation damping of the wobble will commence in order to return the Earth to a minimum energy status. c. The nutation damping can take different forms. If the continental redistribution changed the latitude of the total continental center of mass (which would alter the Earth's angular momentum and rotational kinetic energy) then one or both of the following would occur to maintain the conservation of the above two quantities: - The Earth's rotational velocity would change (i.e., the length of a day would change). - The Earth's core elements (inner/outer cores and densest part of lower mantle) would move. d. There is no proof that the Earth's rotational velocity changed during the Mesozoic (disregarding the insignificant effect of the moon's gravitational pull on this planet), therefore, the Earth's core elements moved away from their current geocentric position. 2. When the core elements moved away from their geocentric position, by definition, the surface gravitation changed; lowest "g" the furthest distance away from the core elements, which would have been at the center of mass of Pangea. 3. The lowered "g" on Pangea accounts for dinosaur gigantism. 4. The core element(s) movement accounts for the massive flood basalt volcanism of the Mesozoic. This type of volcanism is produced by plumes initiated at the core/mantle boundary. 5. The resultant surface gravity gradient around the globe (i.e., lowest at Pangea and highest antipodally) accounts for the extremely high sea levels near Pangea during the Phanerozoic Eon. 6. The core element(s) movement accounts for the Kiaman Reverse Superchron and the Cretaceous Normal Superchron. These are two anomalously long periods when the Earth's magnetic field did not reverse. 7. The changing continental configuration and corresponding core element movement was responsible for many mass extinction events prior to the K-T extinction. Finally, the most powerful support for the GTME comes from the science of paleomagnetism, which I believe substantiates this theory. This is described in detail in the second edition of the book: .................................................................................................
Moontanman Posted May 15, 2011 Posted May 15, 2011 I don't believe any laws of physics must be revised: Briefly, the GTME (Gravity Theory of Mass Extinction) posits the following: 1. Today, the Earth's continental land masses are disributed fairly uniformly around the globe. In the distant past (e.g., when Pangea existed) the distribution did not have this uniformity. When there is a change in continental distribution, several things happen concurrently: a. A wobble of the Earth will occur. b. Nutation damping of the wobble will commence in order to return the Earth to a minimum energy status. c. The nutation damping can take different forms. If the continental redistribution changed the latitude of the total continental center of mass (which would alter the Earth's angular momentum and rotational kinetic energy) then one or both of the following would occur to maintain the conservation of the above two quantities: - The Earth's rotational velocity would change (i.e., the length of a day would change). - The Earth's core elements (inner/outer cores and densest part of lower mantle) would move. d. There is no proof that the Earth's rotational velocity changed during the Mesozoic (disregarding the insignificant effect of the moon's gravitational pull on this planet), therefore, the Earth's core elements moved away from their current geocentric position. 2. When the core elements moved away from their geocentric position, by definition, the surface gravitation changed; lowest "g" the furthest distance away from the core elements, which would have been at the center of mass of Pangea. 3. The lowered "g" on Pangea accounts for dinosaur gigantism. 4. The core element(s) movement accounts for the massive flood basalt volcanism of the Mesozoic. This type of volcanism is produced by plumes initiated at the core/mantle boundary. 5. The resultant surface gravity gradient around the globe (i.e., lowest at Pangea and highest antipodally) accounts for the extremely high sea levels near Pangea during the Phanerozoic Eon. 6. The core element(s) movement accounts for the Kiaman Reverse Superchron and the Cretaceous Normal Superchron. These are two anomalously long periods when the Earth's magnetic field did not reverse. 7. The changing continental configuration and corresponding core element movement was responsible for many mass extinction events prior to the K-T extinction. Finally, the most powerful support for the GTME comes from the science of paleomagnetism, which I believe substantiates this theory. This is described in detail in the second edition of the book: ................................................................................................. Ummm.... No, the distribution of the mass of the earth from the surface would make no difference in the gravitational attraction at the surface. If you were suspended 4000 miles above the surface of an Earth mass black hole you would still feel 1g.
csmyth3025 Posted May 15, 2011 Posted May 15, 2011 (edited) I don't believe any laws of physics must be revised: Briefly, the GTME (Gravity Theory of Mass Extinction) posits the following: 1. Today, the Earth's continental land masses are disributed fairly uniformly around the globe. In the distant past (e.g., when Pangea existed) the distribution did not have this uniformity. When there is a change in continental distribution, several things happen concurrently: a. A wobble of the Earth will occur.... Let's look at this claim a little more closely. The Earth's crust occupies less than 1% of the Earth's volume and its average density is about 3g/cm3. (ref. http://en.wikipedia....rust_and_Mantle ) The volume of the Earth is 1.08321×1012 km3 (ref. http://en.wikipedia.org/wiki/Earth ), which is equal to 1.08321 x 1021m3. If we use the generous estimate of 1%, the volume of the crust is 1.08321 x 1019m3 and its mass is about 3.25 x 1022kg. This is 0.0054 of the Earth's mass. (ref. http://www.wolframalpha.com/input/?i=%281.08321*10%5E12+km%5E3%29%280.01%29%283g%2Fcm%5E3%29 ) There is no doubt in my mind that the break-up of Pangaea led to major upheavals in the geography and lifeforms on the surface of the Earth - as did the break-up of the estimated four (or,perhaps, six) supercontintents that preceded it (in a roughly 450 million year cycle). (ref. http://en.wikipedia.org/wiki/Supercontinent ) I seriously doubt that these comparatively minor reconfigurations of the egg-shell-thin surface layer of the Earth could have the sort of effects on the interior structure of the Earth and on the moment of inertia of the Earth that you describe. I'm sure that our forum members would like to see the calculations upon which your claims are based. Please provide a paper or other source. Chris Edited to specify "break-up" of supercontinents prior to Pangaea Edited May 15, 2011 by csmyth3025
csmyth3025 Posted May 16, 2011 Posted May 16, 2011 (edited) IMO we are getting out of tracks. The prior question is wether gravity has an influence over size of living forms. From Earthling's post #25: 2. When the core elements moved away from their geocentric position, by definition, the surface gravitation changed; lowest "g" the furthest distance away from the core elements, which would have been at the center of mass of Pangea. 3. The lowered "g" on Pangea accounts for dinosaur gigantism. I have no doubt that tectonic activity has played a major role in the evoutionary process and in the periodic mass extinctions that have punctuated the history of life on Earth. I question the soundness of Earthlink's claims about the effect that the formation and subsequent break-up of Pangaea had by means of the extraordinary gravitational asymmetry (quoted above) which he asserts led initially to dinosaur gigantism and then, presumably, to the subsequent eradication of dinosaur gigantism in favor of smaller land animals. It's my belief that the strength of the gravitational field of the Earth has not changed to any significant degree (either locally or globally) over the last 4 billion years. As far as I know, claims that the center of gravity of the Earth has shifted within the interior of the planet are unsupported by any geological evidence or by any credible model of planetary evolution. I again invite Earthling to provide some sort of believable analysis that supports his claim of significant variations in the surface gravity of the Earth. Chris Edidited to correct spelling errors Edited May 16, 2011 by csmyth3025
Moontanman Posted May 16, 2011 Posted May 16, 2011 I agree with csmyth, I would like to see how rearranging the mass of the earth would result in a different gravitational pull at the surface.
michel123456 Posted May 16, 2011 Posted May 16, 2011 (edited) I agree with csmyth, I would like to see how rearranging the mass of the earth would result in a different gravitational pull at the surface. When saying "gravitational pull" it is ment the force at the surface. Taken that Earth's mass has not changed in the last 4 billion years and taken that weight at the surface is function of the amount of mass and to the squared distance (following Newton's law of universal gravitation)* the other way to make the "gravitational pull" change at the surface is to increase the distance. * IOW a larger Earth (with the same mass) would have a smaller "gravitational pull". And one could say that a larger Earth (with the same mass) could be expected to have larger life forms, contrarily to Moontanman's assertion. Edited May 16, 2011 by michel123456
Moontanman Posted May 16, 2011 Posted May 16, 2011 (edited) When saying "gravitational pull" it is ment the force at the surface. Taken that Earth's mass has not changed in the last 4 billion years and taken that weight at the surface is function of the amount of mass and to the squared distance (following Newton's law of universal gravitation)* the other way to make the "gravitational pull" change at the surface is to increase the distance. * IOW a larger Earth (with the same mass) would have a smaller "gravitational pull". And one could say that a larger Earth (with the same mass) could be expected to have larger life forms, contrarily to Moontanman's assertion. Michel, as I said before, all things being equal a large planet will have stronger gravitational pull at the surface than a small planet, you keep trying to change the arbitrarily parameters to suit your self. High gravity would mean smaller animals in general due to the cube square law, low gravity would allow for larger animals. Yes it is possible to conceive of a larger planet with less gravity, a 24,000 mile in diameter planet made of ice would not have as high a gravity as as 24,000 mile planet made of iron but you are only trying to wiggle out of being wrong and you know it. BTW, a larger Earth with the same mass???? Care to add to add a mechanism to that large steaming pile of hot male bovine excrement? Edited May 16, 2011 by Moontanman
michel123456 Posted May 16, 2011 Posted May 16, 2011 (...) High gravity would mean smaller animals in general due to the cube square law, low gravity would allow for larger animals. Yes it is possible to conceive of a larger planet with less gravity, a 24,000 mile in diameter planet made of ice would not have as high a gravity as as 24,000 mile planet made of iron (...) Right. I wonder what we were arguing about. (I have to admit that I didn't get what you meant by "all things being equal" but now i got it) So let's remind the OP In my opinion and some of my own observation, I have come to a teori that,more dense the earth because of increasing gravity(mass),the smaller in size also the life in it. It base on theory about energy. Bigger gravity means more weight,more weight means more energy,so our body need to reduced the size factor to efficient the energy needed. And another factor is,in molecular base,the weight is influenced by the gravity too...so our molecule also become smaller smaller and smaller....... So if one is searching for ET in another planet, they also need to consider size factor. CMIIW Replace the word "Earth" with "planet" and is that so wrong?
Earthling Posted May 16, 2011 Author Posted May 16, 2011 If you search the web for info about the effect of the movement and/or melting of the Antarctic ice cap, you will find various opinions about the induced wobble associated with that mass redistribution. Clearly, the Antarctic ice cap mass is insignificant compared to the total continental land mass which was redistributed when Pangea formed. It follows that a massive wobble occurred when Pangea formed, and the question is: what mechanism dampened out that wobble? Also, when Pangea formed, the total continental center of mass did not remain at the near-equatorial plane where it is today; it was well south of that plane. This movement would have changed the Earth’s total angular momentum (AM), violating a basic law of physics, if nothing happened to offset this lowering of AM. Only two ways of offsetting this change in AM come to mind: 1. The Earth would have to spin at a faster rate (i.e., a shorter day) or 2. Internal shifting of the densest part(s) of the Earth away from the center. I know of no support for ( 1.) above. That leaves the alternate, shifting of the Earth’s inner/outer cores and the densest part of the lower mantle. If this happened, it follows from Newton’s Law of Universal Gravitation, as expressed mathematically in an earlier post, surface gravity on the Earth would have changed. And, it would have lowered on Pangea because the core elements would have moved away from Pangea. Therefore, as Pangea formed: The Earth, in a series of incremental steps over many millions of years, started to wobble as the continental plates of the Earth moved toward Pangea. As the center of mass of the plates moved south of the equator, the (nutation) damping of the wobble forced the displacement of the core elements from their current central position to maintain constant AM. No mass change is needed; no change in the Earth’s volume is needed; no densty change is needed.
Moontanman Posted May 16, 2011 Posted May 16, 2011 If you search the web for info about the effect of the movement and/or melting of the Antarctic ice cap, you will find various opinions about the induced wobble associated with that mass redistribution. Clearly, the Antarctic ice cap mass is insignificant compared to the total continental land mass which was redistributed when Pangea formed. It follows that a massive wobble occurred when Pangea formed, and the question is: what mechanism dampened out that wobble? Also, when Pangea formed, the total continental center of mass did not remain at the near-equatorial plane where it is today; it was well south of that plane. This movement would have changed the Earth’s total angular momentum (AM), violating a basic law of physics, if nothing happened to offset this lowering of AM. Only two ways of offsetting this change in AM come to mind: 1. The Earth would have to spin at a faster rate (i.e., a shorter day) or 2. Internal shifting of the densest part(s) of the Earth away from the center. I know of no support for ( 1.) above. That leaves the alternate, shifting of the Earth’s inner/outer cores and the densest part of the lower mantle. If this happened, it follows from Newton’s Law of Universal Gravitation, as expressed mathematically in an earlier post, surface gravity on the Earth would have changed. And, it would have lowered on Pangea because the core elements would have moved away from Pangea. Therefore, as Pangea formed: The Earth, in a series of incremental steps over many millions of years, started to wobble as the continental plates of the Earth moved toward Pangea. As the center of mass of the plates moved south of the equator, the (nutation) damping of the wobble forced the displacement of the core elements from their current central position to maintain constant AM. No mass change is needed; no change in the Earth’s volume is needed; no densty change is needed. No Earthling, unless the actual diameter of the Earth changed drastically no amount of reshuffling of the Earth's mass would have changed the pull of gravity at the surface, I'll repeat myself, "if you were 4000 miles away from the center of an Earth mass black hole you would still experience the same gravity we do today." a shorter day would also have no discernible effect, no internal shifting would have any effect, where are you getting these ideas from? You really need to provide a link to show some evidence for what you are claiming. Right. I wonder what we were arguing about. (I have to admit that I didn't get what you meant by "all things being equal" but now i got it) I hate it when that happens, sorry i wasn't more precise in my response. So let's remind the OP Replace the word "Earth" with "planet" and is that so wrong? Lets break down the OP into all it's seperate parts In my opinion and some of my own observation, I have come to a teori that,more dense the earth because of increasing gravity(mass),the smaller in size also the life in it. If I understand what he is saying then yes, more gravity would indicate smaller organisms due to the cube square law. http://en.wikipedia.org/wiki/Square-cube_law BiomechanicsIf an animal were scaled up by a considerable amount, its relative muscular strength would be severely reduced, since the cross section of its muscles would increase by the square of the scaling factor while its mass would increase by the cube of the scaling factor. As a result of this, cardiovascular and respiratory functions would be severely burdened. In the case of flying animals, the wing loading would be increased if they were scaled up, and they would therefore have to fly faster to gain the same amount of lift. Air resistance per unit mass is also higher for smaller animals, which is why a small animal like an ant cannot be crushed by falling from any height. As was elucidated by J. B. S. Haldane, large animals do not look like small animals: an elephant cannot be mistaken for a mouse scaled up in size. The bones of an elephant are necessarily proportionately much larger than the bones of a mouse, because they must carry proportionately higher weight. Because of this, the giant animals seen in horror movies (e.g., Godzilla) are unrealistic, as their sheer size would force them to collapse. However, it's no coincidence that the largest animals in existence today are giant aquatic animals, because the buoyancy of water negates to some extent the effects of gravity. Therefore, sea creatures can grow to very large sizes without the same musculoskeletal structures that would be required of similarly sized land creatures. It base on theory about energy. Bigger gravity means more weight,more weight means more energy,so our body need to reduced the size factor to efficient the energy needed. I'm not sure if i really understand this but if I do I think the above link does explain what he is asking. And another factor is, in molecular base, the weight is influenced by the gravity too...so our molecule also become smaller smaller and smaller....... No, gravity (on a planetary scale at least) does not make atoms or molecules smaller... So if one is searching for ET in another planet, they also need to consider size factor. I am quite certain this is true, probably for reasons other than gravity as well, but over interstellar distances it would seem to a moot point.
zapatos Posted May 16, 2011 Posted May 16, 2011 No Earthling, unless the actual diameter of the Earth changed drastically no amount of reshuffling of the Earth's mass would have changed the pull of gravity at the surface, I'll repeat myself, "if you were 4000 miles away from the center of an Earth mass black hole you would still experience the same gravity we do today." a shorter day would also have no discernible effect, no internal shifting would have any effect, where are you getting these ideas from? You really need to provide a link to show some evidence for what you are claiming. To use an extreme example... If 90% of the mass of the earth were at the north pole, are you saying that no matter where you stood on the surface of the earth, you would feel gravity equally?
Earthling Posted May 17, 2011 Author Posted May 17, 2011 Moontanman, It’s all about rotational physics. Anyone not familiar with that will have trouble understanding this. Your statement : "No Earthling, unless the actual diameter of the Earth changed drastically no amount of reshuffling of the Earth's mass would have changed the pull of gravity at the surface..." is incorrect. If you are familiar with angular momentum (and the conservation thereof) you would know that any redistribution of mass on/in the Earth would alter the total angular momentum (AM). In order to conserve AM when the continents coalesced to form Pangea, what mechanism do you suggest acted to maintain total AM? A change in the Earth’s diameter is not necessary for a change in surface gravity. Shifting of the core elements (the densest part of the Earth), based on Newton’s law, must alter surface gravity.
michel123456 Posted May 17, 2011 Posted May 17, 2011 (edited) A change in the Earths diameter is not necessary for a change in surface gravity. Shifting of the core elements (the densest part of the Earth), based on Newtons law, must alter surface gravity. If you put that mathematically, you will see that you need a huge difference in distance. In the formula Taken G is constant m1 is constant (Earth's mass) m2 is the mass of the animal (an elephant) You may want to double m2 and keep F constant: it is a situation where an elephant is twice as big (has twice the mass) but feels the same force (has the same weight). Doubling m2 and keeping F the same means you need to double r^2 as well, which gives an increase of r of a factor 1,41 1,41 Earth's radius means an increase of about 2600 km, which is a huge value IMHO in regard to the doubling of an elephant's mass. I don't know how you can account for such effects only by moving the center of mass and without changing Earth's radius. Besides, I don't know how could the Earth remain a spherical object when its center of mass is not at the center anymore (Or do I misunderstand your proposal?) Edited May 17, 2011 by michel123456
swansont Posted May 17, 2011 Posted May 17, 2011 Moontanman, It’s all about rotational physics. Anyone not familiar with that will have trouble understanding this. Your statement : "No Earthling, unless the actual diameter of the Earth changed drastically no amount of reshuffling of the Earth's mass would have changed the pull of gravity at the surface..." is incorrect. If you are familiar with angular momentum (and the conservation thereof) you would know that any redistribution of mass on/in the Earth would alter the total angular momentum (AM). In order to conserve AM when the continents coalesced to form Pangea, what mechanism do you suggest acted to maintain total AM? A change in the Earth’s diameter is not necessary for a change in surface gravity. Shifting of the core elements (the densest part of the Earth), based on Newton’s law, must alter surface gravity. Reshuffling the mass would change the angular speed, but not the angular momentum. Changing angular momentum requires an external net torque. Reshuffling the mass in any way that still preserves the isotropic distribution, e.g. all the mass in a shell at the mantle, or almost all at the core with a thin shell at the surface will have zero effect on surface gravity, just as Moontanman suggested. As long as the distribution is spherically symmetric and you are on the outside, gravity behaves like all of the mass is at a point in the center. It's an application of Gauss's law. 1
Moontanman Posted May 17, 2011 Posted May 17, 2011 To use an extreme example... If 90% of the mass of the earth were at the north pole, are you saying that no matter where you stood on the surface of the earth, you would feel gravity equally? I doubt that would be possible in the real world, such a concentration of mass would immediately go to the center as the rest of the mass wrapped around it, in such an extreme case you would get the effect of higher gravity above the mass concentration much mike you get with mascons under the surface of the moon. But an example as extreme as yours couldn't be stable for very long even in human terms of time.
Earthling Posted May 17, 2011 Author Posted May 17, 2011 michel123456, Your calculation for the displacement of the Earth’s center of mass of about .41 r (r=radius of Earth) is reasonable. Considering that the Earth’s "core elements", inner/outer core and densest part of lower mantle, make up about 85% of the Earth’s mass, this would not be unreasonable in order to halve the weight of an object at the surface (as in the case of Pangea) as the core elements moved away from Pangea. Since the center of rotation still remains unchanged, the spinning Earth is balanced by the equal moments of inertia: Pangea (low m and high r^2) Earth’s shifted core elements (high m and low r^2) ...where r is distance from spin axis to mass swansont You wrote: "Reshuffling the mass would change the angular speed, but not the angular momentum. Changing angular momentum requires an external net torque." Redistribution of continental mass would change angular momentum if neither of the following happened: 1. The Earth’s spin rate (i.e., angular velocity) did not change. 2. There was no internal redistribution of mass. [i think I posted this previously] We know that total angular momentum cannot change unless, for example, a bolide impact occurs. Unless someone has proof that (1.) above occurred, then (2.) must have occurred. When I use the term "redistribution" of continental mass, I’m specifically referring to a latitudinal change because that would change angular momentum. If you read the prior postings, you will find that the continental redistribution of mass that we are addressing (i.e., the formation of Pangea) is not the "spherically symmetric" one you stated. We are concerned with gravitational changes at the surface of the Earth when there is a major non-symmetrical redistribution of mass within the Earth resulting from the continental redistribution. Based on the above, the core elements had to move off center resulting in a change in surface gravity.
Moontanman Posted May 17, 2011 Posted May 17, 2011 michel123456, Your calculation for the displacement of the Earth’s center of mass of about .41 r (r=radius of Earth) is reasonable. Considering that the Earth’s "core elements", inner/outer core and densest part of lower mantle, make up about 85% of the Earth’s mass, this would not be unreasonable in order to halve the weight of an object at the surface (as in the case of Pangea) as the core elements moved away from Pangea. Since the center of rotation still remains unchanged, the spinning Earth is balanced by the equal moments of inertia: Pangea (low m and high r^2) Earth’s shifted core elements (high m and low r^2) ...where r is distance from spin axis to mass swansont You wrote: "Reshuffling the mass would change the angular speed, but not the angular momentum. Changing angular momentum requires an external net torque." Redistribution of continental mass would change angular momentum if neither of the following happened: 1. The Earth’s spin rate (i.e., angular velocity) did not change. 2. There was no internal redistribution of mass. [i think I posted this previously] We know that total angular momentum cannot change unless, for example, a bolide impact occurs. Unless someone has proof that (1.) above occurred, then (2.) must have occurred. When I use the term "redistribution" of continental mass, I’m specifically referring to a latitudinal change because that would change angular momentum. If you read the prior postings, you will find that the continental redistribution of mass that we are addressing (i.e., the formation of Pangea) is not the "spherically symmetric" one you stated. We are concerned with gravitational changes at the surface of the Earth when there is a major non-symmetrical redistribution of mass within the Earth resulting from the continental redistribution. Based on the above, the core elements had to move off center resulting in a change in surface gravity. Can you back that up with anything but claims? You are suggesting we over turn the laws of physics, at least give us some justification of what you say because it is not true, you cannot, in any way supported by natural processes, move the mass of the Earth around to make the surface gravity stronger or weaker unless you change the diameter of the earth.
swansont Posted May 18, 2011 Posted May 18, 2011 swansont You wrote: "Reshuffling the mass would change the angular speed, but not the angular momentum. Changing angular momentum requires an external net torque." Redistribution of continental mass would change angular momentum if neither of the following happened: 1. The Earth’s spin rate (i.e., angular velocity) did not change. 2. There was no internal redistribution of mass. [i think I posted this previously] We know that total angular momentum cannot change unless, for example, a bolide impact occurs. Unless someone has proof that (1.) above occurred, then (2.) must have occurred. Without a torque, an internal redistribution of mass will not change the angular momentum, it will change the angular speed such that the angular momentum stays constant. So, absent a change in speed, a change in surface mass distribution must be accompanied by a change in internal mass distribution. But there's good evidence that rotational speed has changed over time. When I use the term "redistribution" of continental mass, I’m specifically referring to a latitudinal change because that would change angular momentum. If you read the prior postings, you will find that the continental redistribution of mass that we are addressing (i.e., the formation of Pangea) is not the "spherically symmetric" one you stated. We are concerned with gravitational changes at the surface of the Earth when there is a major non-symmetrical redistribution of mass within the Earth resulting from the continental redistribution. Based on the above, the core elements had to move off center resulting in a change in surface gravity. Again, there will be no change in angular momentum. The mass distributions you are discussing are in the roundoff error of the gravitational acceleration — it currently varies by just a fraction of a percent due to deviations from uniformity. Plate tectonics won't cause that big of a change.
Earthling Posted May 18, 2011 Author Posted May 18, 2011 Moontanman, In response to my reply to michel123456, you wrote: "You are suggesting we over turn the laws of physics...." Please explain ths statement. You also wrote : "...you cannot, in any way supported by natural processes, move the mass of the Earth around to make the surface gravity stronger or weaker unless you change the diameter of the earth." As I have posted previously, this statement is not true. The theory in question has proven this. If the Earth’s core elements never moved away from their central position, then there would always have been a geocentric axial dipole (GAD) magnetic field. If you study the Pangea ‘A’ vs. Pangea ‘B’ controversy you will find that there wasn’t a GAD magnetic field on the Earth during most of Pangea’s existence. Why not????? Paleomagnetists came up with a "fudge" scheme to try to explain this. The current theory explains this very simply: If the Earth’s core elements moved off center, then by definition, there was no GAD during the period when the core elements were displaced. Swonsont, You wrote: "But there's good evidence that rotational speed has changed over time. " Please provide references to support the change in the Earth’s rotational speed during the existence of Pangea. You also wrote: "Again, there will be no change in angular momentum. The mass distributions you are discussing are in the roundoff error of the gravitational acceleration — it currently varies by just a fraction of a percent due to deviations from uniformity. Plate tectonics won't cause that big of a change. " If you read my earlier posts I stated that the condition in which angular momentum could change, is a bolide impact. I do not understand your second "roundoff error" statement. However, as I have also stated several times, latitudinal movement of large continental plates would change angular momentum(AM) if there was nothing to offset the change in AM. Since we know that AM must be conserved I listed two possible offsets, one of which was the rotational speed of the Earth, which in the first statement of yours that I quoted above, seems to be your choice. Please provide an answer to the question I posed. -1
Moontanman Posted May 19, 2011 Posted May 19, 2011 Moontanman, In response to my reply to michel123456, you wrote: "You are suggesting we over turn the laws of physics...." Please explain ths statement. You also wrote : "...you cannot, in any way supported by natural processes, move the mass of the Earth around to make the surface gravity stronger or weaker unless you change the diameter of the earth." As I have posted previously, this statement is not true. The theory in question has proven this. If the Earth’s core elements never moved away from their central position, then there would always have been a geocentric axial dipole (GAD) magnetic field. If you study the Pangea ‘A’ vs. Pangea ‘B’ controversy you will find that there wasn’t a GAD magnetic field on the Earth during most of Pangea’s existence. Why not????? Paleomagnetists came up with a "fudge" scheme to try to explain this. The current theory explains this very simply: If the Earth’s core elements moved off center, then by definition, there was no GAD during the period when the core elements were displaced. No, all you have done is make claims that are contrary to the laws of physics, you made the strange claims, it's up to you to support it with more than "I said so"
michel123456 Posted May 19, 2011 Posted May 19, 2011 (edited) (...)As I have posted previously, this statement is not true. The theory in question has proven this. If the Earths core elements never moved away from their central position, then there would always have been a geocentric axial dipole (GAD) magnetic field. If you study the Pangea A vs. Pangea B controversy you will find that there wasnt a GAD magnetic field on the Earth during most of Pangeas existence. Why not????? Paleomagnetists came up with a "fudge" scheme to try to explain this. The current theory explains this very simply: If the Earths core elements moved off center, then by definition, there was no GAD during the period when the core elements were displaced. Very interesting. I found some interesting articles about GAD. Including this one from University of Arizona. I haven't got the time to read it completely, but it seems to disagree with your statement. Edited May 19, 2011 by michel123456
swansont Posted May 19, 2011 Posted May 19, 2011 Swonsont, You wrote: "But there's good evidence that rotational speed has changed over time. " Please provide references to support the change in the Earth’s rotational speed during the existence of Pangea. You've moved the goalposts. "Over time" ≠ "during the existence of Pangea" 620 MYa the length of the day was about 20 hours http://adsabs.harvard.edu/abs/1997GeoRL..24..421W You also wrote: "Again, there will be no change in angular momentum. The mass distributions you are discussing are in the roundoff error of the gravitational acceleration — it currently varies by just a fraction of a percent due to deviations from uniformity. Plate tectonics won't cause that big of a change. " If you read my earlier posts I stated that the condition in which angular momentum could change, is a bolide impact. I do not understand your second "roundoff error" statement. However, as I have also stated several times, latitudinal movement of large continental plates would change angular momentum(AM) if there was nothing to offset the change in AM. Since we know that AM must be conserved I listed two possible offsets, one of which was the rotational speed of the Earth, which in the first statement of yours that I quoted above, seems to be your choice. Please provide an answer to the question I posed. How much reshuffling of mass do you contend will happen by moving the continents around? How big of an effect on gravity will there be as a result?
Earthling Posted May 19, 2011 Author Posted May 19, 2011 Moontanman, You wrote: "No, all you have done is make claims that are contrary to the laws of physics, you made the strange claims, it's up to you to support it with more than ‘I said so’. " I have asked you previously to state the law(s) of physics that I have violated. You have not provided a substantive answer yet. If you cannot answer the question then please admit your statement is wrong. michel123456, I tried to download the pdf link you provided but was not able to retrieve the file. Could you identify the statements you are referring to? Note that I used the word "fudge" in the earlier post because the paleomagnetists assume that the core elements were always geocentric. They then introduced new types of magnetic fields (quadrapolar and octupolar) to explain the Pangea ‘A’ vs. Pangea ‘B’ overlap. What they never explain is how or why a GAD (geocentric axial dipole) field could morph to the quadrapolar or octupolar fields and then back again. As I mentioned, if the core elements shifted (per this theory), there would not be a GAD magnetic field and no need to introduce the two anomalous magnetic fields. Swansont, I have not "moved the goalposts", you have picked a time period not relevant to the subject at hand, which is the GTME theory. This theory posits that as Pangea formed, the core elements moved away from their current geocentric position and that total angular momentum DID NOT CHANGE because one of two things occurred to prevent that change: Either: 1. The Earth’s angular velocity changed (i.e., increased, meaning a shorter day) or 2. The Earth’s core elements moved off-center. Therefore, it is you who have "moved the goalposts." You wrote: "How much reshuffling of mass do you contend will happen by moving the continents around? How big of an effect on gravity will there be as a result? " I can’t give you an accurate answer because it depends on the displacement of the core elements. Also, the lowering of "g" near Pangea increased the height of sea levels near Pangea, effectively increasing the mass (in addtion to continental mass) that came into play. The surface gravity would have varied around the planet because the distance from the new center of mass to points on the surface would be different. Lowest "g" on Pangea would be in the region near the equator and highest "g" at high north and south latitudes. One could guess at "g" based on the size of the largest dinosaurs or largest pterosaurs....but this would only be a guess.
Moontanman Posted May 19, 2011 Posted May 19, 2011 Moontanman, You wrote: "No, all you have done is make claims that are contrary to the laws of physics, you made the strange claims, it's up to you to support it with more than ‘I said so’. " I have asked you previously to state the law(s) of physics that I have violated. You have not provided a substantive answer yet. If you cannot answer the question then please admit your statement is wrong. http://en.wikipedia.org/wiki/Gauss%27s_law_for_gravity The gravitational flux through any closed surface is proportional to the enclosed mass. http://en.wikipedia.org/wiki/Shell_theorem Now you keep saying that the mass of the Earth was asymmetrical and this resulted in gravity at the surface being more or less 50% of what it today. You fail to show any mechanism for this and you ignore the fact that earth is not asymmetric in it's interior composition and due to it's size and internal temps could not be asymmetrical enough to have any significantly different gravity from one area to another. You also falsely suggest that the mass of the crust can significantly change the gravity if it shifts, this is trivially falsified but yet you make the claim, the rules require you support it with more than "I said so" I have shown how mascons can vary the gravity field by tiny amounts but your contention is trivially falsified by physics, now Mr. Earthling, according to the rules of the forum you are the one who has made the unusual claim, it is up to you to support it, now show how what you are saying is possible or admit you are spouting nonsense and go on to something else...
michel123456 Posted May 20, 2011 Posted May 20, 2011 michel123456, I tried to download the pdf link you provided but was not able to retrieve the file. Could you identify the statements you are referring to? Note that I used the word "fudge" in the earlier post because the paleomagnetists assume that the core elements were always geocentric. They then introduced new types of magnetic fields (quadrapolar and octupolar) to explain the Pangea ‘A’ vs. Pangea ‘B’ overlap. What they never explain is how or why a GAD (geocentric axial dipole) field could morph to the quadrapolar or octupolar fields and then back again. As I mentioned, if the core elements shifted (per this theory), there would not be a GAD magnetic field and no need to introduce the two anomalous magnetic fields. This is the full link. It is a 22 pages pdf, I cannot post it here. http://www.geo.arizona.edu/Paleomag/book/chap10.pdf only some excerpts "During the 1950s and early 1960s, paleomagnetic evidence for continental drift was attacked by detractorswho questioned the validity of the GAD hypothesis during the Paleozoic and Mesozoic. Irving (1964) discussed this “nondipole hypothesis” and concluded that it was a “hypothesis of desperation, useful at this stage only to those anxious to avoid implications of paleomagnetism.” With subsequent expansion of paleomagnetic data and development of plate tectonics, the fundamental validity of the GAD hypothesis is now quite firmly established." The past 5 million yearsIn discussing Figure 1.9, we found that the geomagnetic pole does a random walk about the rotation axis.The average position of the geomagnetic pole over the past 2000 years is indistinguishable from the rotation axis. In Chapter 7, we analyzed paleomagnetic data from Holocene lavas of the western United States. Increasing numbers of VGPs were used to determine the “paleomagnetic poles” shown in Figure 7.5. Resulting poles fell within 3° of the rotation axis, and the confidence limit, A95, decreased to 3.7° when 30 VGPs were averaged. It is apparent that the time-averaged Holocene paleomagnetic field in the western United States was geocentric axial dipolar within a 95% confidence limit of ~3°. We will return to further discussion of this data set below. Opdyke and Henry (1969) determined mean paleomagnetic inclinations from 52 Pliocene–Pleistocene deep-sea cores. These mean inclinations are shown in Figure 8.2 and are found to closely match the inclinations predicted by a GAD: tan I = 2 tan l (Equation (1.15)). More detailed evaluation of the GAD hypothesis was made possible by compilation of paleomagnetic data from 4580 lavas with ages in the 0- to 5-Ma interval (Merrill and McElhinny, 1983). The first-order time-averaged geomagnetic field over the past 5 m.y. was found to be axial geocentric dipolar within confidence limits of ~3°. This data set is sufficiently large to allow resolution of second-order deviations, which are discussed below. The above analyses confirm the validity of the GAD hypothesis for the past 5 m.y. So in the geologic time interval for which the most rigorous tests are available, the GAD hypothesis is confirmed with an uncertainty of ~3°. Older geologic intervalsThe task of evaluating the GAD hypothesis for geologic time intervals older than 5 m.y. is complicated bymotions of lithospheric plates, the phenomena that we’re going to use paleomagnetic data to investigate. These evaluations can be divided into tests of (1) the geocentric dipolar nature of the paleomagnetic field and (2) the axial alignment of the geocentric dipole. From the Late Jurassic to the present, marine magnetic anomalies provide determination of relative plate motions. At least during the Cenozoic, continents can be accurately reconstructed to their relative positions by using these anomalies. The dipolar nature of the time-averaged geomagnetic field can be tested by comparisons of paleomagnetic poles from the different continents as sequential reconstructions to older geologic times are performed. For example, if continents are reconstructed to their relative positions at 30 Ma, paleomagnetic poles from rocks of this age should agree if the time-averaged geomagnetic field was geocentric dipolar; failure of the poles to agree could indicate a nondipolar field. Such analyses have confirmed the geocentric dipolar nature of the geomagnetic field during the Cenozoic and Late Mesozoic to a precision of about 5° (e.g., Livermore et al., 1983, 1984). Other tests have similarly confirmed the geocentric dipolar nature of the time-averaged paleomagnetic field during Phanerozoic time (e.g., McElhinny and Brock 1975; Evans, 1976). But how do we test whether this geocentric dipole was aligned with the Earth’s rotation axis? Comparisons with independent determinations of paleolatitude are required. Although imperfect and of limited precision, paleoclimatic indicators are the best available independent measures of paleolatitude with which to compare paleolatitudes determined from paleomagnetism. Latitudinal zones of climate exist fundamentally because the flux of solar energy strongly depends on latitude. The present mean annual temperature is 25°C at the equator but is only –25°C at the poles. Numerous biologic and geologic phenomena are controlled by climatic zones: Organic reefs (corals), evaporite deposits, and red sediments are predominantly found in equatorial regions or in temperate arid zones symmetric about the equator; and glacial phenomena are found in or surrounding polar regions. Paleoclimatic spectra are histograms of the latitudinal distribution of these paleoclimatic indicators. Comparison of paleoclimatic spectra in present latitude with spectra in paleolatitude determined from paleomagnetism is the basic method for evaluating the axial alignment of the geocentric dipole for remote geologic times. Irving (1964) presented a thorough discussion of paleoclimatic and paleomagnetic data. The fundamental verification of the GAD hypothesis by favorable comparison with paleoclimatic indicators has not significantly changed since the synthesis by Briden and Irving (1964). The following examples are adapted from their analysis. In Figure 10.1a, the present latitudinal distribution of modern organic reefs is shown. The observed distribution is symmetric about the equator, and almost all occurrences are within 30° of the equator. But the present latitudinal distribution of fossil organic reefs (Figure 10.1b) shows many fossil reefs at latitudes >30°N, and the distribution is very asymmetric about the equator. It is highly unlikely that this distribution resulted from a drastically different pattern of climatic zones at the time these fossil reefs formed. Furthermore, the distribution of fossil reefs in paleolatitude determined from paleomagnetism (Figure 10.1c) exhibits the anticipated symmetry about the paleoequator. This analysis indicates that the distribution of fossil reef deposits is consistent with the GAD hypothesis.
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