I've shown you the numbers... they were what I put in my reply.It makes no sense to try to invalidate physics based of a projected size and mass of a creature known only by a drawing of one bone that has been lost for over a century.They were extracted from:
Procedings of the National Academy of Science, U S A. 2007 July 24;
Volume: 104(30), Pages: 12398-12403.
Published online 2007 July 3. doi: 10.1073/pnas.0702040104.
PMCID: PMC1906724
Copyright © 2007 by The National Academy of Sciences of the USA
The aerodynamics of Argentavis, the world's largest flying bird from the Miocene of Argentina
Sankar Chatterjee, Department of Geosciences, Museum of Texas Tech University, Box 43191, Lubbock, TX 79409-3191;
R. Jack Templin, retired aeronautical engineer, formerly with the Canadian National Research Council in Ottawa, 2212 Aster Street, Ottawa, ON, Canada K1H 6R6;
and Kenneth E. Campbell, Jr., Department of Ornithology, Natural History Museum of Los Angeles County, 900 Exposition Boulevard, Los Angeles, CA 90007
Edited by Steven Vogel, Duke University, Durham, NC, and accepted by the Editorial Board June 6, 2007
Author contributions: S.C. designed research; S.C. performed research; R.J.T. contributed new analytic tools; K.E.C. studied the fossil; S.C. and R.J.T. analyzed data; and S.C., R.J.T., and K.E.C. wrote the paper.
Received March 5, 2007.
ABSTRACT
We calculate the flight performance of the gigantic volant bird Argentavis magnificens from the upper Miocene (~6 million years ago) of Argentina using a computer simulation model. Argentavis was probably too large (mass ~70 kg) to be capable of continuous flapping flight or standing takeoff under its own muscle power. Like extant condors and vultures, Argentavis would have extracted energy from the atmosphere for flight, relying on thermals present on the Argentinean pampas to provide power for soaring, and it probably used slope soaring over the windward slopes of the Andes. It was an excellent glider, with a gliding angle close to 3º and a cruising speed of 67 kph. Argentavis could take off by running downhill, or by launching from a perch to pick up flight speed. Other means of takeoff remain problematic.
You can read the paper here: The aerodynamics of Argentavis, the world's largest flying bird from the Miocene of Argentina
First of all, I am not trying to "invalidate physics" ... if anything, I am using physics to try and find an answer to an observed impossibility, a fact or set of facts that don't seem to fit our understanding of what is possible ... and I have NOT used only one example. I have provided many examples... and there are a lot more.I have already provided information on Dinosaurs where we have much more than "one bone...lost for over a century". It is you who is not bringing anything except ignorant denial of anything that doesn't seem to meet your world view. You are cherry picking your data to try and negate it.
In fact, the official estimated weights of those megafauna are underestimated because even the paleontologists were having trouble accepting what they were finding based on the calculations... so they "lightened" them up... they fudged the math. For example, had they used the straight forward result from the Square Cube Law calculation, one animal that was listed with an estimated weight over 300,000 lbs., would have been listed at a minimum 490,000 lbs. Also, a couple of the estimates were probably properly "adjusted" for the fact that the tails were longer and more "whip-like" than the comparable Diplodocus skeleton.
Finally, the weight ranges given in the references that I quoted are not just simple Square Cube Law calculations based solely on the length of the animal... they are more complex calculations, adjusting for length, depth, and width of major portions of the beast, as well as adjustments for differences that may exist in void spaces (i.e. increasing lung capacity required for larger animals) in the bodies. These are not numbers that are just tossed out there without considerable research and thought behind them, as you seem to imply.
As for those lost bones (there were actually two, a tail vertebra and 14-15 foot long Femur), they were collected by a well respected paleontologist, Edward Drinker Cope, who found and catalogued many other specimens that are still extant... and none of his descriptions of them were fabricated or exaggerated. His work is reliable on the fossils that still exist in his catalogues so why should we doubt the existence or truthfulness of his description of the few that have been lost or destroyed?
The idea that the earth once rotated every two or three hours is not consistent with known physics.
And again you are wrong. The idea that the Earth once rotated every two or three hours is not really disputed... and it is indeed consistent with known physics. Any dispute is about WHEN it may have done that.However, while it may be a viable hypothesis to explain the existence of megafauna, I do not subscribe to that hypothesis. That was a hypothesis put forward by ThePythonicCow, I think.
I gave my example -- admittedly a worst case -- because your articles don't mention anything except length.
Your example was not a good "worst case" example because you really don't know how to do it. Had you followed the logic of the Square Cube Law, you would have completed your example and found that your scaled up Chestnut Sparrow would have a body almost 10 feet long... instead of the 3-4 foot body of a California Condor you were comparing it to... and seen the total absurdity of your example. Or, had you superimposed an outline of your sparrow on the outline of a California Condor, you would see that they are not at all similar in build. On the other hand, if you superimposed a California Condor outline on the Argentavis magnificens outline, extrapolated from its skeleton, you will find that ALL of its proportions are essentially identical. On one it is reasonable to use a straight forward Square Cube calculation... on the other, it is not. Guess which is reasonable... hint, it isn't yours.Actually, they and I have spoken of other things "except length"... they and I referred to the other specimens as being "proportionate" to the comparable animals where we knew the complete size. Length is used because they ARE proportional in their other measurements, which makes length a good determiner of the multiplier, just as my explanation of why your "admittedly a worst case" scenario, which, I might add, you did not divulge until I showed you the errors, was based on the requirement for proportional scaling.
Your projected weights based on the square cube law are troublesome enough when applied to creatures we can touch and measure and observe. they border on nonsense when they are based on a few bits and pieces that have been mineralized.
First if all there IS no "troublesome" issue with the Square Cube Law when applied to creatures we can touch, measure, and observe... it works every time (that's why they call it a "law") when it is applied properly... something you did not do. Secondly, js1138, the projected weights are NOT MY PROJECTIONS but rather are the accepted weight ranges from the science of Paleontology. These were not just calculated by me or the author of this article; they can be found in many authoritative mainstream sources. It is YOU who refuse to look at the facts... it is you, an admitted amateur, who apparently would prefer to ignore them and call them "nonsense" when leading scientists in the field such as Dr. Robert Bakker accepts them as valid. I provided you a chart of the known brachiosaurs that showed the known sizes of some species (which were already far beyond the limits of modern animal weight and strength), such as the Diplodocus, and those of some incomplete skeletons in which the animals size is extrapolated from comparisons of the found parts to similar parts in a known related species. I also provided information on animals such as the Teratorns where we DO have complete skeletons (for some Teratorn species we have hundreds of skeletons).
they border on nonsense when they are based on a few bits and pieces that have been mineralized. If you dispute this, let's see the actual numbers and actual calculations.
I do indeed dispute your allegation that established science is nonsense. I am not going to cut and paste pages and pages of numbers and calculations that you can find for yourself... since you are the one disputing well established and accepted science. If you want to review the actual numbers and the calculations involved as well as the theory and practice that they support, you can start with this book:
"Dinosaur Systematics: Approaches and Perspectives", by By Kenneth Carpenter and Philip J. Currie, Published 1992, Cambridge University Press, 334 pages, ISBN 0521438101You can read some of this book on line. It has been quite a few years since I read this book... but it has the information and calculations you want to check.
You have to understand that science has a feature called consilience. Everything has to be consistent with everything else.
You see, JS, I do understand that... and here we have a set of facts that are NOT consistent with what we think is correct.Your arguments are based in uniformitarianism... the assumption that the natural processes operating in the past are the same as those that can be observed operating in the present.. a theory that is increasingly being challenged by facts that don't fit. When the facts don't fit, you don't ignore the facts to continue embracing a failed theory... you discard it and start looking for a theory that incorporates those inconvenient facts as well. Other theories have been proposed to better fit the facts as we find them. Primary among these is catastrophism, where sudden changes in the conditions of the Earth may result in major changes in the flora and fauna of the Earth. One example of this theory is the mounting evidence that the impact of an extraterrestrial object caused a catastrophe that destroyed the dinosaurs... and indeed, that such condition changes are probably responsible for many if not most evolutionary changes to life forms on earth. Punctuated Evolution may be a result of catastrophism changing the conditions under which life must exist and causing adaptations for mere survival.
When the facts don't fit the theory, ANY alternate explanation that fits the facts is fodder for investigation until it is falsified. However, sweeping the facts under the rug is not appropriate science.. in fact it is not science at all... that's dogma.
Excellent points that underscore the fact that it’s far easier to take potshots at something than to understand it and grapple with what is revealed to be inexplicable given a current understanding. I wonder if the much higher oxygen content of the air could support cellular function while reducing other requirements having to do with structure and function. Maybe the velociraptor wasn’t really that fast and everything was sort of a molassass world.
Great post and thanks for staying focused on the article and topic.
The idea is not mine orginally. Sometime a year or three ago I read an article that presented the case for this, but I can't find the article now, and can't present a good case either way. So at this point, it's just an hypothesis, that a few (such as myself) may find intriguing, but that others (likely most others) will dismiss or ignore, for one reason or another.
When are you going to post the actual calculations?