venerdì 9 dicembre 2011

Dinosauri, giganti, gravità

Anche se consideriamo tutte queste immagini come false (e possono tranquillamente esserlo):
Mi sono sempre chiesto la ragione dell’esistenza di megafauna e megaflora.
Ci sono due ipotesi che mi “intrigano”. 
Una è questa (che, tra l’altro, concorda con l’Ipotesi Nemesis):
L’altra è stata elaborata da un geologo statunitense, John Stojanowski.
Prima edizione:
Seconda edizione:
I suoi commenti (nickname “Theorist”) sono disponibili online, qui:

1. The Earth’s cores’ position (both inner and outer) are dependent on the positioning of the continental plates.
2. The plates have rearranged their position throughout time, sometimes coalescing to form a supercontinent, such as Pangea.
3. The Earth’s surface gravity is directly and primarily determined by the position of the cores.
4. When the cores shift from their central location, surface gravity decreases at points furthest away from the shifted cores and simultaneously increases at surface points that are closest to the shifted core. A surface gravity-gradient results.
5. When Pangea formed, surface gravity was much lower on Pangea but much higher on the opposite oceanic side of the Earth.
6. The gravity gradient would result in the lowest surface gravity near the central, or equatorial, part of Pangea. Therefore, the largest life forms for a specific species, for a specific time period, would be in this region. (Note: this is why I made the comment that Quetzalcoatlus remains, which were found in Texas would not be found in either high northern or southern latitudes).
7. Larger terrestrial and marine life forms became possible. As in the current time, there is always a diversity of size regardless of the strength of surface gravity. In other words, lower gravity does not force all life forms to grow larger.
8. As Pangea broke apart, surface gravity on Pangea increased and the rate of increase was greatest when the continents started rapidly moving apart longitudinally approx. 68-65mya. The result was an accelerated extinction rate for both terrestrial and marine life.
9. Since the time of the K-T boundary, the rate of increase of surface gravity has decreased as the continents have attained a more even global distribution as the cores have returned to a central position.
10. When the cores were shifting, they magnified the effects of flood basalt volcanism. This type of volcanic activity originates at the core/mantle boundary. This is why the massive Deccan Traps volcanism was active 68-65mya.
The idea of variable gravity is not preposterous as someone has stated. The blue whale cannot be compared to Mesozoic sea-going reptiles for one basic reason. The reptiles were carniverous, unlike the blue whale. Some of them were very large but being carniverous, they had to move quickly. Whether in pursuit or ambush mode, they had to move at a speed that the blue whale could not. Thus, their size and shape were constrained. I don't agree with some of Holden's conclusions. The basic premise that gravity was less during the reign of the dinosaurs......I do agree with.
The size of some of the dinosaurs gradually increased and was at a maximum near the end of the Jurassic Period, as was pointed out. Their size diminished until the transition period (of about 65mya). Clearly, if the gravity explanation is viable, the Earth's surface gravity (on Pangea but not necessarily the entire surface) had to be increasing from the end-Jurassic through the transition period. And, the rate of change of the increase had to be much higher at the transition period to account for the final demise of the dinosaurs, pterosaurs and other Mesozoic life forms.

This is the headline of an article in the in January 2008. It describes the research of a Japanese scientist who studied the flight of the albatross. His conclusion, as noted in the headlines, is that the large pterosaurs could not fly. I should rephrase that and say that they could not fly if they were here today.
Qui l’articolo scientifico:

I don't think most people who have seen the re-creations of the pterosaur would believe they could not fly over 65 million years ago. Therefore, something was significantly different. I believe that difference was gravitational.
Neither Expanding Earth nor spin variations can account for significant variations in surface gravity. The only reasonable theory is the one that links the movement and positions of the continents to the movement of the Earth's core(s). That movement would have a significant influence on surface gravity because of the inverse square (of distance) effect. The consolidation of the continents (i.e., Pangea) would cause a significant change in surface gravity. If this theory is correct, and I think it is, surface gravity began to slowly increase as Pangea rifted and increased significantly when the continents moved apart rapidly about 65mya. It would have increased after that and gradually increased to its present value as the core(s) returned to their central, current position.
I was able to find some more information on Quetzalcoatlus. The Illustrated Encyclopedia of Dinosaurs, by Dougal Dixon, states that Quetzalcoatlus had a wingspan of about 37 feet and "Despite its great size the skeleton was lightly built and the whole animal may have weighed not more than 100kg (220 lbs)."
The Japanese scientist, Katsufumi Sato, who concluded that the pterosaurs would not be able to stay aloft, concluded that the maximum weight for a flying animal is 40kg (88lbs). What is interesting is the ratio of the two weights 88/220. If the basis of this analysis is correct, this would imply surface gravity was almost 1/3 of today's value at the end of the Cretaceous.......a stunning conclusion and even less than what I assumed.
There are a few assumptions here. The first one is that both the pterosaurs and the birds the scientist is studying use a vertical, and not a running, takeoff. Actually, the scientist does not address takeoffs. He asserts that these large pterosaurs could not flap their wings fast enough to stay airborne.
Also, the core-shift theory would entail variations in surface gravity.....the maximum low gravitational value at the center of mass of Pangea, basically in an equatorial location. If true, then we would most likely find the remains of Quetzalcoatlus in what was equatorial regions in the late Cretaceous.... not in places like Canada, Australia or other higher latitude locations.
You are probably correct that there is no (known) data to support any kind of large gravitational changes during the Phanerozoic. But, this subject, to my knowledge, has not been studied. We're not addressing the conventional "gravitational anomalies" caused by variations in sub-surface densities. And, your statement that there is no "core shift theory" is not correct, although it might not be formally known by that name.
As far as the locations of the poles is concerned, there was substantial wandering of the poles during the Mesozoic, although not abrupt
Let me repeat:
I challenge you, as I requested previously, to supply a reference to a peer-reviewed source that concludes, based on angle of repose or anything else, that there was never any fluctuation in the Earth’s surface gravity.
I posed the question about the Superchrons, not to obfuscate, but to provide one of the strongest pieces of evidence that the G-Theory is correct. The foundation of G-Theory is the movement of the Earth’s cores. If the cores did not shift, then G-Theory can be tossed in the trash bin of theories that have not panned out. All the other circumstantial evidence, such as the gigantism of dinosaurs, the anomaly of giant pterosaurs flying, the decline and disappearance of many terrestrial and marine life forms toward the end of the Mesozoic, including all the sea-going reptiles and the ammonites, would have to be explained by some other theory.
I have given one other supporting piece of evidence concerning the shifting of the cores and that was the massive flood basalt volcanism which occurred during the periods in question. I think it is reasonable to assume that some major core anomaly, which has not happened with the same intensity in the last 30 plus million years was responsible. What could that be? I don’t believe anyone responded to that evidence.
G-Theory posits the following concerning the shifting of the cores:
1. When Pangea was being formed, from basically the Carboniferous through the Permian Periods, the consolidation of the continental plates caused a corresponding movement of the cores in the opposite direction.
No other theory can explain non-polar-magnetic-reversal for a period of about 56 million years. There was no other process that has been identified that could act continuously over such a long time period.
2. When Pangea began to break apart, another long term event, the rate of plate separation was much higher during the Cretaceous Period, the time of massive extinctions.
No other theory can explain non-polar-magnetic-reversal for a period of about 40 million years. There was no other process that has been identified that could act continuously over such a long time period.
Is it just a coincidence that the REVERSED magnetic polarity of the first Superchron occurred when the cores, according to G-Theory, moved away from the Earth’s center and the second Superchron’s NORMAL magnetic polarity occurred when the cores, according to G-Theory, moved toward the Earth’s center?

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