Science a GoGo's Home Page Forums General Discussion General Science Discussion Forum Mansfield's Earth Formation Hypothesis: Evidence.

No logical error was made - it was a hypothetical situation intended to produce the maximum gravitational deviation possible. The whole point was to create the situation most likely to produce the effect you claim, and then analyze the impact that would have.

Secondly, your assumption could very well be wrong. No one has ever measured the rate the earths core moves in response to an uneven distribution of mass - or even if it occurs. Keep in mind that the force on the core will be less than the force pretty much anywhere else within the earth (as the core will be at/close to the center of rotation). Likewise, the mantle is very viscous and may be nearly solid near the core itself. As such, it is very well possible that the movement of the core to correct for shifts in mass may be slower than the continental drift forming those disequlibria. If the rate of continental drift forming those disequlibria occurs faster than shifts in the position of the core, you would end up with something close to the model I analyzed.



But I will - the pictures, as drawn, reflect the absolute maximum amount of deviation you could get. And while the "real-world" may not have occurred to the maximum extent, those deviations from equilibrium are the only way in which you could create a gravitational abnormality.



Sorry, you are wrong.

In the first picture we have a disequlibria - there is more mass between the axis of rotation and pangea than there is from the axis of rotation and the anipode to pangea. This occurs because the core is centered at the axis of rotation, while pangea (with its greater mass) is off to one side.

That unequal distribution of mass also creates a gravitational disequilibrium in pangea compared to its antipode.

In picture 3 we have restored equilibrium - the core is now off-set towards pangea's antipode. Since the core is denser than the mantle, this shifts mass towards pangea's antipode. The net effect is the amount of mass (i.e. in kg) between the center of rotation and pangea is now the same as the amount of mass between the center of rotation and pangea's antipode.



1) Your math is wrong, ergo your last response is invalid.

2) Even if we take your case at face-value, without values your claims are meaningless - you would need pretty large movement of the core to get a d2/r2 ratio to provide a 1-2% change in surface gravity.



Still doesn't fit the fossil record. The major periods of breakup were not associated with mass-extinctions, but rather increases in species diversity:




Three points:
1) The shifts in body shape you claim occur were not universal across all large caldes - which is what would have to happen if gravity was the cause.

2) Large sauropods are found at all elevations near the KT-boundary; picking the one continent where there numbers appear to have dropped doesn't bolster your argument, but instead is a clear-cut case of you cherry-picking data to "prove" your model.

3)Sauropods are found upto the KT boundary, but not beyond it. So it is fair to claim they all disappeared at the KT boundary.


But in this context, rapid can be very well defined. For your model to work the breakup must occur faster that the core can shift.

You've provided no values, so we cannot put a limit on "rapid". None-the-less, the geological record and fossil record do not agree with your hypothesis. Pangea broke up over a >100 million year period; not exact consistent with a model that requires rapid shifts.



Cut-and-pasting from wikipedia, I see. But your complaint doesn't alter my criticism one bit - the evidence for a earth-altering impact that occurred when the dinos went extinct is very strong. Had you read all of the wikipedia article you copied from, you'd have noticed this sentence:

Due to the volcanic gases and subsequent temperature drop, the formation of the traps is seen as a major stressor on biodiversity at the time. This is confirmed by a mass extinction topping 17 families per million years (about 15 families per million years above the average)[5]. Sudden cooling due to sulfurous volcanic gases released by the formation of the traps and localised gas concentrations may have been enough to drive a less significant mass extinction, but the impact of the meteoroid that formed the Chicxulub Crater (which made a sunlight blocking dust cloud that killed much of the plants, called an impact winter) made this one of the most pronounced mass extinctions in the Phanerozoic.[6]

Or, in other words, the traps were insufficient to drive the mass extinction - and there is good evidence they were also caused by a meteorite, not changing geology.


Couple of points:
1) Asteroid impacts would not necessarily create conditions that lead to good fossilization, which would be a pre-requisite for increased numbers of fossils. In fact, the K-T mineralogy suggests that the impact resulted in acidification, which degrades, not preserves, fossils.

2) The extinction was not thought to be instantaneous, but rather thought to occur over several thousand years. Once again, that would not produce large fossil beds, but rather dwindling rates of fossil production. Geologically, that is very fast, ergo appearing as an immediate loss of fossils.

3)There are several references in the scientific literature showing an abrupt end to dinosaur fossilization at the KT boundary; consistent with a rapid, but multi-generational extinction:

Archibald, J.D. 2000. Dinosaur abundance was not declining in a "3 m gap" at the top of the Hell Creek Formation, Montana and North Dakota. Comment. Geology 28(12): 1057-1184.

Bohor, B.F., D.M. Triplehorn, D.J. Nichols, and H.T. Millard, Jr. 1987. Dinosaurs, spherules, and the "majic" layer: A new K-T boundary clay site in Wyoming. Geology 15: 896-899.

Bryant, L.J. 1989. Non-dinosaurian lower vertebrates across the Cretaceous-Tertiary Boundary in Northeastern Montana. University of California Publications in Geological Sciences 134.

Moreover, at least one of the kinds of deposits you expect (i.e. jumbles from instantaneous mass-death) have been found:
Bourgeois, J.T., T.A. Hansen, P.L. Wilberg, and E.G. Kauffman. 1988. A tsunami deposit at the Cretaceous-Tertiary boundary in Texas. Science 241: 567-570.



What I mean is that your model of rapid gravitational changes would be accompanied by specific geological evidences: changes in the formation of sedimentary rocks, changes in paleomagnetic data (whose traces are directly proportional to the strength of gravity at the site of formation), etc.

These changes are not seen. I provided links in a previous post relating to paleogravitaitonal measures; if the changes you claimed occured, we would see them in those recored - there would be significant deviations in those measures is rocks of the same age, located in different regions of the earth. That simply is not seen.



Some irridium is present in volcanic flows. However, the concentrations are much lower than what is found in the KT boundary, nor is there any volcanic mechanism by which it could be distributed as evenly across the earth as it is in the KT boundary, and thirdly, irridium in volcanic flows is always associated with volcanic material - be it solidified magma or volcanic particulates in sedimentary rock. This is not seen at the K-T boundary, where instead the irridium is contained within a layer consistent with condritic meteors that lacks significant amounts of volcanic dust/minerals.



Maybe you should check out those links I provided, because:

1) The fact that large petrosaurs could fly was validated experimentally - as in they made, and flew, a scale model.

2) Those computer models you so readily dismiss are known to be extremely accurate - the same models are used to design planes, trains and automobiles, and are know to replicate the real world to an extremely high degree of accuracy.

3) Your Japanese group also used a computer model - but one of highly questionable relevance. They took a range of measurements from existent birds and then used to measures to derive a cutoff for where birds can no longer fly. Compare that to the models used by other groups - models which apply the well-understood physics of aerodynamics and materials to predict the aerodynamic qualities of any object.

Not to mention, petrosaurs are not birds - morphologically & aerodynamically they are very different. Likewise, their environment was different as well - high O2 levels as one example.

So why would you consider the Japanese computer model better than the ones used to design and build airplanes - computer models, which as I mentioned above - have been validated through the construction & flight of a model petrosaur.

Or, take the example of the model used for suaropods - they took known strengths of biological materials, known morphology of the sauropods, accepted ranges of sauropod masses and mass distribution, and known newtonian physics and simply calculated the force.

What is questionable about that? How is that less valid than measuring various physical traits of things that fly and then saying anything that lacks those traits cannot fly?



And you provided ZERO evidence to support that sized shift. In fact, we can prove it to be impossible - the inner core accounts for ~2% of the earths mass, while the outer core accounts for ~30%. Keep in mind that for a constant mass, the only factor that will change gravity is distance - GM/r2. For these calcs' I'll treat the cores as point masses - a process which will maximize the gravitational difference; in the real world the actual differences will be less. So the max change in gravity would be:

Inner core:
r with core centered = 1 earth radius, core sitting on the bottom of the oceanic plate = 2 earth radi.

Fgunshifted = G(0.02)/12 = 0.02G of gravity from the core, therefore 0.98G from stuff inbetween

Fgshifted = G(0.02)/22 = 0.005G from core, for a total of 0.98+0.005 = 0.985G

That 1.5% less gravity on pangea; ignoring any "extra" gravity from pangea itself.

Outer + Inner core:
Fgunshifted = G(0.32)/12 = 0.32G of gravity from the core, therefore 0.68G from stuff inbetween

Fgshifted = G(0.32)/22 = 0.08G from core, for a total of 0.68+0.08 = 0.76G.

So the absolute maximum theoretical gravitational change possible, under the impossible assumptions that:
a) the inner + outer core is located on the bottom of the sea opposite pangea,
b)the mass of the 2 cores is concentrated into an infinity dense point,
c) no mass fills the space previously occupied by the core
d) pangea has no "extra" gravity due to its mass

The maximum loss of gravity you can have is 0.24G.

If you simply move the cores, so that the outer edge of the outer core sits against the oceanic crust opposite pangea, and assume the material that fills the space has the median density of the mantle, your maximum change becomes ~0.1G

So once again, basic physics and a basic grasp of math disproves your model.

Bryan