I see what you're getting at, and that's a good point. It is true that the number of species and genera of an animal family is not the only indicator of how well that family is doing. But, we hominids are relative freaks in the animal kingdom with our merged chromosomes, unprecedented brains, and our extreme agression toward similar but different races of sapien, let alone other hominids. It is very rare for an organism to be successful for the reasons that homo sapiens is successful.


D'oh! You're right about where India was located. What the heck was I reading in the New York Times science section in the mid-90's, then? I guess I should have read something else.

So, we've got falling sea levels, the Deccan volcanism, and the meteor. I wonder how widely agreed scientists are on the chronology of these events, and what would be good to read as far as the evidence for that chronology. I'll post a question on Yahoo!Answers to that effect.

Here's a link to that:
http://answers.yahoo.com/question/index?qi...mp;msgr_status=

Say, I notice we just got "hot topic" designation, over 9000 views, and this is the 100th reply. We're smokin' the charts.

The Wetumpka Impact Crater is the only confirmed meteorite crater in Alabama, United States. It is located east of downtown Wetumpka in Elmore County, Alabama. The crater is 7.6 km in diameter and its age is estimated to be about 83 million years.

That was before the Yucatan.

A huge outpouring of the earth's interior that occurred over much of present-day India 65 million years ago came from the boundary between the earth's lower mantle and its molten iron core some 1,800 miles beneath the surface, scientists have determined. The work is published in today's issue of Science.

By measuring the oldest samples of helium ever obtained -- helium trapped in rocks 68.5 million years old -- scientists at the University of Rochester and the Institute of Human Origins in Berkeley, Ca. show that volcanic activity incubated for 3.5 million years before erupting, rapidly blanketing the Indian subcontinent with more than 1 million cubic kilometers of lava. The stack of lava is now known as the Deccan Traps.


Now, y'all tell me which one was first!

Oh, and explain why dinosaurs did not drag their tails!

And the more y'al try to figure out the past, the fatter, uglier, and more disease filled humans become!!!!

I'm not sure where y'all are going. The Wetumpka impact of 83mya seems to be a mini version of Chicxulub. Coincidentally, they both struck areas that were then shallow seas. The only question I would have about Wetumpka is whether there were any extinctions associated with it. If none, it's another reason to question the impact extinction scenario.

I'd like to see the Science article about about the Deccan Traps....I'll have to search the web to see if I can find any reference to it.

Not sure what you are referring to when you ask "Now, y'all tell me which one was first!"

Why did dinosaurs not drag their tails? Well, they were not reptiles nor amphibians. Since they don't move around close to the ground on splayed legs, a dragging tail would be like you walking around dragging a potato sack. But, if you had a very long heavy neck, a raised tail would offset that weight.

Deccan Traps

Fabrosaur,

The impactor at Wetumpka is thought to have been about 300m in diameter, the Chicxulub impactor has been estimated at 10km in diameter. While the Wetumpka impact may have been spectacular on a local scale it is unlikely it would have led to global species extinctions.

Yes, I agree. What I was referring to was local extinctions, either flora or fauna.


Also, I have to correct the comment I made about the location of India during KT. It was on a tectonic plate moving on the EAST side of Africa, not the west side.

I wish Pilgrim Shadow would come around. Here's my favorite post of his:


Well, it seems that placement of the Deccan volcanism by mainstream geology is convenient if one is looking for something akin to "Earth-shattering" side effects of such a contraction.

Now, here I go again citing a mid-90's news story in Science Times (the weekly science section of the New York Times) for which I searched through miles of microfilm one day, unsuccessfully: "The Earth's Core May Be a Gigantic Crystal Made of Iron." Anyone else know about this? A man sought to explain why seismic test waves did not survive the trip through the Earth's core, and a previous theory was that it was too liquid. His proposal was that the core was a superdense iron crystal, with atoms packed together like carbon atoms in a diamond -- much closer than in conventional iron.

One of the problems that he struggled with was that the proposed crystal structures could only exist at pressures and temperatures which exist so far below the surface of the Earth, and therefore couldn't be produced artificially or otherwise for laboratory study. But, I remember reading that he tried to figure out which of multiple crystalline models was correct based on which crystal could exist at what temperature, since nobody knew how hot the core really was. He found one that would have worked if it so happened that the core was such-and-such a temperature (can't remember).

Now, here's what I remember thinking as I read this: Doesn't everyone agree that the Earth has cooled over geologic time? Therefore, what would happen as the Earth cools to thresholds at which one kind of super-dense iron crystal can no longer exist, and a denser one can? You will have a threshold effect on the density of the planet, followed by a semi-violent change of size (depending on how long it takes to unfold).



Ah, but what drives plate tectonics to drive the Americas farther away from AfroEurAsia? It's like I said about the Hawaiian hot spot in the very middle of the Pacific. The granite continental plates are being pushed into a state of balance around the planet since the K-T contraction.


Aw, Pilgrim! You know the type of gravity increase being proposed would not affect the orbit of anything.


Of course, the paleogravity theorist seeks to explain how dinosaurs moved on land at all, if not bounding along at least as well as Bakker maintained them capable. And like Bakker also said, their being capable does not mean they spent any larger a percentage of their time doing it than modern warmblooded mammals -- less than one percent of their time. Therefore, after we've uncovered and studied 100 sets of dinosaur footprints, we'd be lucky to have the prints of one dinosaur in fighting shape sprinting his best.

I feel so safe arguing against Pilgrim Shadow now that it seems he's not going to jump back in. Nope, I think he's gone. Neeever comin' back. Nope. Never.

Actually, Dino, the Moon's orbit would definitely be affected by the Paleogravity Theory.

I agree, the Earth's mass would be the same so the net effect of gravity would be the same at any given distance. However, paleogravity assumes the Earth was larger in the past. The effect of this is to bring more of the Earth's mass closer to the Moon - not to mention the effect of the Moon on the tides would be significantly greater! Both these factors would have a significant effect on the Moon's orbit.

There would be a lot of calculation required and it would vary greatly according to how much larger the Earth was in your theory, but it should be possible to disprove paleogravity if the calculations don't match with what we see today.

Just how much of a reduction in gravity (and consequent expansion of the Earth) are we talking about here? If it is significant then I'm doubtful you will be able to show paleogravity possible by calculating how it would affect the Moon's orbit. If the gravity reduction has to be insignificant to match the data about the Moon we have observed then your theory is insignificant to why dinosaurs were so large.

The mass of the Earth on one side of the Earth would be closer to the moon. But, the mass on the far side of the Earth would be farther away at the same time. The overall mass of the Earth would not change and the center of gravity would not change orbit. The law of physics which states that all of the mass of a body of matter behaves as if it is concentrated in the center of gravity would apply in the contracting Earth scenario. That is precisely why my theory is vastly more plausible than the expanding Earth theory.


If you apply the gravity-distance formula, I believe the result of an approximate 600-mile increase in Earth's diameter would result in an approximate 25% decrease in surface gravity. But, I think that it would take less of an increase -- a single digit percent -- to produce noticeable gravitational definition in the physiology of organisms before and after the change.

I agree the overall mass of the Earth would not change and nor would the centre of gravity. Gravity, with respect to two very large bodies like the Earth-Moon system, is slightly more cmplicated than "The law of physics which states that all of the mass of a body of matter behaves as if it is concentrated in the center of gravity" and this is why we have the Moon slowly moving away from Earth as it orbits (tides). Please read this article. I'll paste the relevant snippet below...



Before you say "there is a tidal bulge on the opposite side of the Eath", it is further away from the Moon so has much less oppositional gravitational effect.

It is posited in prehistory the Moon was closer to Earth and therefore the tides were larger and these had a more significant effect on the Moon vis-a-vis it's spiralling orbit. If, in your scenario the Earth was larger then this effect would be exaggerated by that. Also, if the Earth was larger would it have rotated slower one assumes - but assumption is bad and again, this is something you will have to work out because it is important for determining the nature of the Earth-Moon mechanics.

Now, I'm not saying this rules out paleogravity but it does mean you will have to consider and calculate how your 'larger Earth' affected the Moon's orbit (and vice-versa, how the Moon being closer would affect the Earth's rotation) and this could either support your theory or kill it stone dead.

I asked the following question on Yahoo!Answers:

"Is there anyone proficient in math who wishes to prove/disprove a paleogravity theory?"

I recieved the following reply:


Here's a direct link:

http://answers.yahoo.com/question/;_ylc=X3...28140244AAncBYp

Oh God, I didn't realize how simple that was. I knew that.

I know what you're saying though, Leonardo. Yes, the bulge of tidewater on the side of the Earth nearest the Moon has a more significant effect than on the opposite side. Over the course of so many millions of years, a double-daily megamountain of water has to be considered. I will need to be able to prove mathematically whether our observations of today support my idea, or whether a convenient meteor or super-eruption would have had to be in the picture for my theory to hold up -- or whether I need to give up. I'll have to dust off those old math books.

While I'm a believer in the increase in gravity from the Mesozoic through the present, I don't believe the answer is a contracting Earth. There isn't any viable explanation or evidence for contraction. "The Earth's core may be a gigantic crystal made of iron" doesn't seem plausible based on current scientific knowledge. Experts in seismic tomography, with their 'P' and 'S' waves, have pretty much confirmed the liquidity of the molten core. The liquid core is a much better explanation of the Earth's magnetic field and it's reversals.

And, just from a non-scientific, common-sense point of view, a contracting Earth would result in an inundation of the continents with enough water to submerge the world.

I'm sorry, the gravitational change will have to come from some other source.

The splitting apart of the Americas and Afroeurasia, the Hawaii hot-spot... and mid-ocean rift formation/plate subduction would cover up the evidence, as those processes are continual. We would be looking for episodes in Earth's geologic past when subduction outpaced seafloor formation. Like a coupon sticking flat to a supermarket conveyor belt... covered up!


Ah, a liquid! Well, just like the mercury in a thermometer, a liquid iron core still cools over time and gets smaller, and if MY attempt to explain why the shrinkage could be episodic is out the window, there could still be another one.


Oooh. Gotta like that one. Yes, the ocean water. The levels do rise and fall, and in fact they were falling from 70-65 million years ago, not rising. But, I can say this: The water cycle of the Earth is not a completely closed cycle. I remember some discussion as to whether the Earth's water comes from comets pelting the atmosphere over the eons, and whether the regular achievement of escape velocity of water vapor molecules keeps up with it all the time. While the rising and falling of ocean levels is fairly well understood, I'm not sure that all causes besides polar ice cap freezes and thaws have been ruled out.

I will post the question on Yahoo.

My question is at:

http://answers.yahoo.com/question/;_ylc=X3...29130027AA4OjkB

So far the most productive answer is this: a link to a page answering a related question by someone else, provided by "Jared Z."

<a href="http://www.madsci.org/posts/archives/may97...73527.Es.r.html" target="_blank">http://www.madsci.org/posts/archives/may97...73527.Es.r.html</a>



Ms. Sara Seager sounds like she knows what she's talking about, though elsewhere she says something about the greenhouse effect that I believe is politically biased. But, I would have to say this lends credence to the inundation scenario as stated by Fabrosaur.

Another contributor (Richard R) has recommended a book.

The theory about the Earth's contraction is known as the Geosyncline Theory from the late 19th and early 20th century.

One famous geologist who supported this theory was Eduard Suess.

The following is from a recent book: 'Earth' by Richard Fortey, page 148,149:

"As we have seen, in the ineteenth century, and in the early part of the twentieth, there had been a strong school of geologists who attributed tectonics to a shrinking earth. After all (so they supposed) , the earth had cooled from its hot 'primeval condition' ; thus it would shrink, and, as it did so, mountain ranges would result. Suess evidently believed in such as mechanism when he contemplated the intensely folded rocks of the Swiss Alps. He realized that the recumbent folds there indicated that the surface must have contracted, or shortened: such folds 'have directed attention anew to the diminution of the earth's circumference,' as he wrote. Recall too, that early estimates of the age of the earth was based on the idea that it was cooling progressively. Discovery of radioactive 'heating' turned the tables................"

I've heard that paleogravity was discussed a hundred years ago, but I misplaced the web page where I saw that information posted. It seems that this book you suggest could bring me up to speed, and so I requested it at my local library -- along with "Life and Death of Planet Earth."

So far, the biggest issues with my ideas seem to be:

1) The effect of a contracting Earth and corresponding tidal effects on the lunar orbit.

2) The effect that would be expected on ocean levels is the opposite of what's observed in the geologic record.

The discovery of a mummified hydrosaur in 1999 in North Dakota is relevant to this thread.

A three and a half ton animal sprinting at 28 mph?

If those numbers are right, gravity had to be less than what it is today.

The White Rhinoceros weighs in at up to 3,600kg and can run at 30mph. There is no requirement for gravity to be less for hadrosaurs to be as fast. This would have been a short-burst speed, not a steady running gait speed.

I'm not sure that's a valid comparison. Hadrosaurs appear to have much smaller and less well developed forelegs.
They do not appear to be built for high speed. Even today, tetrapods that can run swiftly have legs that are close to the same length.

Most animals (if not all) use their hindquarters for the power in fast running gaits. This gives animals of large size with large muscle mass to body weight ratios and well-developed hindquarters an advantage when running. I don't see why smaller forequarters would be an issue when it probably ran on two legs but walked on four.

The evidence from the hadrosaur fossil indicates it had a larger muscle mass to body weight ratio than first thought. This is not only an indicator of a more powerful and (estimated) faster animal, but in lower gravity environments the animal would not have needed this large muscle mass to body weight ratio to develop a relatively fast running gait.

While it might seem to, on the surface, support paleogravity, I don't consider that it does.

If you are correct about the bipedal running, then that is even more support for a lowered paleogravity.

To image that, in current gravity, a three and one half ton animal, running bipedally, could outrun the fastest human in a 100m dash is unrealistic. Since one foot must support its entire weight along with the propelling force necessary to sprint , the stresses generated would be tremendous. Not only that, a hydrosaur fleeing from predators would have to run a lot more than 100m. The energy expended would be enormous.

And, at 28mph, any misstep, any stumble, would be a life ending event for a three and a half ton bipedal animal.

Why is it unrealistic? Simply because you scale up based on the known bipedal organisms living today? Dinosaurs were, according to this fossil, heavily built. While that means they had more mass to crash, it also means they had more mass to absorb an impact. Again, while the stress on the joints of the animal would have been commensurately larger, simply saying they are tremendous does not support paleogravity. You'll have to show these stresses could not be borne in a 1g environment.

And why would it have to run more than 100m? Maybe it's predators were only capable of short dashes as well and were primarily, therefore, ambush hunters. Perhaps the predators strategy was to provoke a fall by startling the prey? All this is speculation, though, and not support for paleogravity.



Obviously, if the estimates by the scientists are correct, you are wrong as the animals assuredly either were able to fall without killing themselves or were so sure-footed they rarely fell. You make up your mind which option is more feasible.

As far as bipedal vs. quadripedal, I make the very simple observation that there were many more large bipedal animals in the Mesozoic than today. That supports paleogravity. It stands to reason that, whatever number of legs are practical for supporting a given body weight in a given gravity, then: fewer legs in lower gravity, more legs in higher gravity. That is what we would expect to see to satisfy the need for support and stability. The example of dinosaurs is absolutely extreme in this regard.

Dragging recent discoveries into the thread is cool.

Hey, "attakkdog" on Yahoo answered my ques on ocean levels at:

<a href="http://answers.yahoo.com/question/index;_y...03140040AADTbYX" target="_blank">http://answers.yahoo.com/question/index;_y...03140040AADTbYX</a>



Ah-ha! That's the other explanation for why ocean levels fell 70-65 million years ago. There was unprecedented plate subduction going on, because Pangaea started splitting apart and formed deep trenches that had not pre-existed. Glaciation isn't the only thing that does it. So, despite an Earth contraction, there may have been enough glaciation from the Deccan volcanism's "nuclear winter" effect, and many deep ocean floor trenches opening up where there had previously been none, to cause the oceans to drop anyway.

No disrespect, Dino, but balance is more a factor than the number of legs. Bipedal dinosaurs had large, heavy tails which were used as a counterweight around the pivot of their legs. While we see many large, bipedal dinosaurs this is only relative to our perspective of 'large'. The truly large dinosaurs were all quadrupeds. As I suggested to Fabrosaur, if you want to suggest bipedalisim supports paleogravity you'll have to show how the stresses on a large bipedal dinosaur (such as hadrosaurs or the large predators) would be too great for the animal to support in a 1g environment. If you can't show that then statements such as 'bipedalism supports paleogravity' are simple speculation and non-educated opinion (I don't mean non-educated as in anyone is uneducated, I mean not validated by actual data).



Where is the evidence deep ocean trenches did not exist pre-Pangaea? The theory of continental drift implies it is a continuous process and did not start with Pangaea, but began billion of years before that, perhaps even as soon as the Earth cooled enough for continental plates to form. The continents being consolidated in a single landmass does not imply there is not plate subduction happening in areas where plates meet under the unified ocean. I'm afraid you are trying to make the theory fit your conclusion, not the other way round.

My responses to the above are:

Bipedal organisms living today, and the comparison to those in the Mesozoic is a valid way to draw conclusions. One has to ask, why in the last 65my have no bipedal animals evolved to a size anywhere close to those of the Mesozoic? I could be wrong, but I don't believe any have exceeded one half ton. As far as those dinosaurs having skulls and limb bones that could withstand an impact of a body with momentum of 3.5 tons times 28mph, you'll have to show that bones can withstand an impact of that magnitude.

Not having to sprint more than 100m is not a realistic assumption. Carnivorous predators hunted in packs; they weren't just ambush predators. Known theropod trackways verify their pursuit strategy.

Neither of the above two options. You are making the assumption, which is the crux of this thread, that scientists assume that the effective weight of that hadrosaur then, is the same as it would be today.

Without having a real live hadrosaur, it's impossible to satisfy your request. Does that mean a prior lower gravity cannot be proven? No, some other method will be found to verify that. The irony of our discussion is that we are concerned about a hadrosaur, which is a flyweight compared to the sauropods.

As far as the Maastrichtian regression is concerned, the experts believe it was caused by rapid sea floor spreading. It wasn't related to glacioeustasy because there were no polar ice caps at that time. Regardless, they don't believe that there was a differential between the amount of crust subducted versus the crust rising from the ridges. In other words, crust out equals crust in.

The only way to say that the larger size of the dinos is irrelevant to gravity is to say that they were almost certainly made out of some kind of super stuff uncommon to animals today, and that evolutionary development of this stronger flesh was such a rare and wonderful accident of nature that: closely related modern animals (birds, crocodiles) cannot re-evolve it. I think it is far safer to assume that if gravity changes, then whatever life forms are pre-existing will naturally evolve to scale up or miniaturize on down. They will distribute their weight among a different number of limbs. The maximum-sized skyscraper that you would be able to build would change. The maximum height that a tree could grow would change. Of course animals would too. Why wouldn't they? Dinosaur size fits the paleogravity picture in the most obvious way, moreso than the fact that the only surviving line (birds) have hollow bones to reduce their weight. For the purpose of flight, yes, but that is still as relevant as the fact that their closest living relatives (crocs) now bask in the neutral buoyancy of fresh water. This is how we would have expected to see a gravity-driven selective process to influence the animal kingdom, and this is what is reflected by the big-picture evidence.



Ow, good one. It is incorrect to say, "there may have been... many deep ocean floor trenches opening up where there had previously been none." How about this: Whatever force for the creation of deep sea trenches existed before the Pangea break-up, more of such force probably existed during and afterwards."

And to answer Fabrosaur, I callenge that scientists know that there has been no net loss of sea floor, and that studies were done to make sure. I don't think anyone thought that such a study was needed, but I'd better get my read on before I say any more on it. And no ice caps at the time, huh?

Fabrosaur and Dino,

I will refer you both again (fabro for the first time actually) to the article at TalkOrigins which specifically shows, by using biomechanics, that dinosaurs were quite capable of attaining the size they did in a 1g environment. We have a much more accurate picture of hadrosaurs now that this newest fossil has been found so you can apply biomechanics to show whether your paleogravity idea is required for their locomotive abilities given their size. As I have said - a few times now - it's no good just speculating reasons, such as 'super-stuff tissue' to try to disregard a normal (1g) gravity environment...you have to show how it is not possible. Use biomechanics, analyse and calculate the stresses involved - no, Fabrosaur, we don't need a living hadrosaur provided we have an accurate enough idea of their general anatomical structure, which this new fossil should give us.



Again, Dino, I'm sorry but this reasoning doesn't make sense. Continental drift doesn't 'stop' or 'slow down' during supercontinent phases, it is a continuous process. I don't think you will be able to use continental drift to explain ocean levels rising and falling.

Edited because I forgot the link!!!

I looked at the link you provided. I don't know anything about Wayne Throop but I believe he is missing the forest from the trees.

It is totally irrelevant whether the largest known African bush elephant is 16,000lb, 20,000lb, 24000lb or somewhat higher. We could quibble about the maximum weight a human being could attain. Is it 1000lb, 1100lb, 1200lb, etc?

What is the maximum weight of known sauropods? With the logic that you are using, an elephant could, barring any environmental constraint (excepting gravity), attain the same weight. I say, no way.

I'm not passing judgement on the Holden Limit, the Holden Number, etc. I'm saying that the known maximum size of animals, when there are enough to arrive at a reasonable sampling, whether they be elephants, humans or any other, provide a good indication of the maximum size attainable for a specific gravitational value.

Your comment on continental drift and sea level is not accurate. Actually the term "continental drift" has been replaced with "plate tectonics." When there is rapid creation of ocean crust at the ocean ridges, there is corresponding transgression on the continents because the rising upflow is very hot and expanded and displaces water onto the continents. Likewise, when the that process slows down, it cools down and the effect is regression.

Yes! I asked the following question on Yahoo!Answers:

Is it true that glaciers are known NOT to have been forming in the millions of years leading up to the K-T? ...Even though the Deccan volcanism was going on, which one would think would reduce the sun's rays reaching the Earth, and ocean levels were dropping?

mountaingym answered:


Link to the question:
<a href="http://answers.yahoo.com/question/index;_y...05170933AARHHTb" target="_blank">http://answers.yahoo.com/question/index;_y...05170933AARHHTb</a>

If it's not glaciation that's causing a drop in ocean level, then what the heck is it? Obviously major changes in the shape of the Earth's crust are likely to change the capacity of the ocean, and affect sea levels.

And as far as having to show how the size of dinos "was not possible" in 1G, I (for one) am not saying, "impossible." Anything is possible.

I'm saying that paleogravity does not require 1G dinosaur weight to be impossible. It only has to make 1G dinosaur weight less practical in order to affect the direction of animal evolution. And, a new environmental stress doesn't have to be so dramatic that it sends a horde of mighty beasts crashing to the ground all in one dramatic day to cause extinction. It only has to curtail the reproductive success of one group of animals against competing groups of animals over long stretches of time, perhaps until a routine cataclyzm (such as a meteor impact) causes the prevailing evolutionary results to play up. That's what is reflected in the fossil record. There are not fossils that point directly to the dinosaurs' killer, such that a bunch of CSI investigators would have fun with, analyzing a big skeleton for the evidence. Fossils from 70-65 mya show dinosaurs dying from the same stuff they always died from throughout the Mesozoic. That's because changes in the reproductive success of an animal do not show up in fossils. There is only a change in the frequency in the occurrence of the fossils -- that is the evidence. Paleogravity fits that body of evidence.

It is a more difficult evolutionary feat for an animal to develop extremely large size, than to stay within bounds that do not so much challenge the constraints of physics. That's all it takes. When we say that dinosaur gigantism seems utterly improbable for land animals in 1G, we are in good company with all the scientists of past decades who believed they must have been swamp creatures. These scientists' points of view were validated by years of study, observation, and analysis -- even if they were wrong about the neutral buoyancy explanation. They had a point. There's nothing uneducated about taking another look at their way of seeing dinosaurs and saying, "maybe there is another way besides neutral buoyancy that explains why they were so large."

That's what I put in one of my posts some time ago, and it so happens there's been a discovery in the Bahamas of one of these crocodiles -- it apparently lived there as recently as the arrival of humans.

Here's a link to a pic of the skull, where you can click to the corresponding news article:

http://www.livescience.com/php/multimedia/...amas%20Sinkhole

The original posts reminds me of Pandas. They sleep all day, roll when they need to go somewhere, and spend hours upon hours eating. It made me imagine dinosaurs in a new way. Panda's too are one of the oldest animals on earth. Nice thread.
I can imagine dinosaurs being heavy and lazy lol.

Hello, all. I joined, I must confess, just to ask a simple question of you all; particularly of Dinotheorist but it does relate to others. My question is, simply, are you all willing to concede that statements such as

"Another way of saying that dinosaurs appear to have been too large to support their body weight is this: that dinosaurs appear to have been lower-gravity organisms." - (www.dinotheorist.com)

are based on a false premise (and the above then follows on with a false dichotomy) and not supported by actual evidence but, in fact, are in direct opposition to current science? Are you willing to concede that the general consensus amongst scientists who are seriously studying the matter, in paleontology, biomechanics, etc. is that dinosaurs were quite capable of supporting themselves and locomoting on a 1G Earth? And, further, are you willing to cease implying (or outright stating) otherwise?

This link, http://www.talkorigins.org/faqs/sauropods.html , has come up a few times here, but I would also point you to:
http://www.ucmp.berkeley.edu/diapsids/saur...nosauridae.html
wherein T. rex is described to be a "fairly fast" runner at 10-20 MPH.
And Manchester University has recently backed up these assertions when modeling five separate meat-eaters, finding that they basically agreed on T. rex speeds (they also found that Compys may have been able to run at a staggering speed of nearly 40MPH!). No one argues any longer that Apatosaurus, for instance, had trouble supporting their weight and that they did indeed graze and herd. And while they may not have been much for running, they weren't exactly immobile. And... a 75 foot 25 ton animal with a multi-ton whip-like (literally, according to some) tail really isn't an ideal target for most predators.

Also, I'm perplexed by the number of arguments I commonly find on the net where a dinosaur's speed is argued as 'slow' but the relative context of their peers and prey isn't taken into consideration. "Slow" is an entirely subjective pronouncement (comparisons to humans and other non-relevant animals is... pointless, I think we can agree?). A T. rex running flat out may indeed have a chance of catching a hadrosaur, for example, which has a top speed which is 5 - 10 MPH faster but who may not be as quick in a sprint (which is another thing to consider in the argument that higher gravity supposedly necessitates more supporting limbs - gravity is not all that's in play here) and tend to herd. And it may have had a very good chance of snagging one of us in our current chair-dwelling configuration.

But I digress... it's the first question I'm most keen to see any answer on. Dinotheorist, others, are you willing to concede this?

Thanks for your time.

In the interest of fairness I should mention that, since I haven't heard a response, I went ahead and blogged about my issues with Dinotheorist's ideas.
http://www.gwangivalley.com/2008/02/23/run-rex-run/
(Someone asked why I wouldn't do this via e-mail. The reason is that I don't like having these sort of discussions 'off the record', so to speak. That's why I came here first.)
I'm still keen to hear any responses.

Hi gwangivalley, and welcome to UM.

I'm not sure if dinotheorist or Fabrosaur are still around but I'm glad you asked the question of whether their views are fixed or they are truly considering this topic from an investigative pov.

One further issue I have with the paleogravity theory is it's assumption that the Earth has been contracting over it's entire history so surface gravity should have been increasing in each geological age, yet dinosaur species actually grew more massive from era to era of their [dinosaurs] existence. This would seem to be contrary to what the theory proposes and indicates this theory does not, in fact, consider conditions from the beginning of the planet, but is a 'gap' theory attempting to explain a bounded scenario without thought to the theory's implications on preceding ages of the planet.

I couldn't agree more, Leonardo. The very fact that the largest pterosaurs, for instance, appeared at, not the beginning, but the end of the era suggests a fundamental flaw in the notion (and let not the casual reader forget, we're talking about millions of years here). These are animals whose very livelihood was tied to gravity and atmospheric density. Tie that with the fact that the giant insects of these ancient eras could not have lived in a lower density atmosphere. We know quite certainly that the oxygen content of the atmosphere was around 30% higher than today when these huge bugs were around. This oxygen richness __inside a dense atmosphere_ was critical to these giant insects existence because it allowed them to respirate _at all_ via their tracheal system. A lower gravity does not allow for such an atmosphere to exist.

I'd very much like to see this... well, I now consider it to be in the "old wives' tale" category.... this falsity routed out of popular notion. It does nothing but confuses the issue for those attempting to learn or explore and clouds the water for those who haven't sought to test out information on their own (especially those who take "I once heard" notions as factual).

Hello qwangivalley,

In response to your skeptical view of the possibility of a lower paleogravity I would reply:

1. You are right about the largest pterosaurs evolving later than the smaller ones. I believe this happened exactly for the reason we are talking about.....gravity was increasing then. In order for those smaller pterosaurs to survive they had to "solve" the increasing gravity problem. They did this by increasing their wing area to mass ratio. So, what seems like a contradiction with a larger pterosaur succeeding a smaller one isn't really a contradiction at all.

2. The circumstantial evidence of the lower paleogravity is substantial. The life forms that were gigantic relative to today is enormous. Just look through the threads on this website. Recently there was a post on the giant "Devil Toad" which is reportedly to have been 10 pounds, 16 inches long. There were clams six feet in diameter and you know how big some of the largest dinosaurs were.

You have to ask yourself how this could have happened. Even if no one can give you a satisfactory answer, that doesn't falsify the premise of a lower paleogravity. Also, I don't believe oxygen levels were a deciding factor because, as I mentioned, there were clams and other marine life that were also gigantic.

Sorry it took so long to reply, I have had an ongoing family emergency.


Concede? No, I actually feel pretty good about what I said.


That's fine, I'll read that too after I finish this reply.

The “false premise” that dinosaurs were too heavy to support their weight was believed by generations of educated men who dedicated their lives to studying dinosaurs. I mention it because -- yes -- it supports my arguments, which I concede are far less humble than my unfinished biology degree.

Modern researchers ARE continually stacking new evidence that:

> Dinosaurs were NOT swamp animals who relied on the neutral buoyancy of water for support of their body weight. They occupied the role of land animals.

> Dinosaurs were highly active.

Scientists are not looking for, or continually discovering new evidence that dinosaurs lived in 1.00G. The question of gravitational definition is mudded/clouded by the suggestion that it is a reactionary idea, coupled with those old notions that were blown out of the swamp water by Bakker and others -- and therefore cannot be dignified by any consideration in the scientific community.

What I will concede is that IF my hypothesis turned out to be correct, it would be a most confounding thing that a biologist WITH a degree did not think of it instead of me. But, that sort of thinking didn't stop Gregory Mendel from discovering genes and it won't shut me up either.


Yes, I have said that the largest animal that may evolve in any given gravity cannot be as large as the largest that may evolve in lesser gravity, for the same simple reason that a building or a tree could not be as large.

What I'm proposing is that within any geologic period that is puctuated by an increase in surface gravity, animals will continue to evolve larger and larger right up until the increase. Then, it is the largest animals which will suffer the worst from the increase. The largest sauropods, for instance (which died out at the end of the Jurassic) were succeeded by the cretaceous alamosaurs whose camarasaur-like physiology appeared to be a compromise between the brachiosaur design for sheer height, and the diplodocus family's features which allowed it to attain maximum feeding height by rearing back on its tail in a tripod stance.

That is not to set dinosaurs as a benchmark of maximum size to which no animal can ever evolve to be as large in 1.00 G. But, such an accomplishment would probably have to take place over MORE millions of years than before, require a more advanced genetic "state of the art," and is less likely to happen at all than in the mesozoic.

The fact that pterosaurs' "very livelihood was tied to gravity" is to say that they were HIGHLY SPECIALIZED to operate against gravity. Now here's where I would say, ADAPTED and SPECIALIZED are not exactly like terms. Birds are very well adapted against the force of gravity. So well adapted, in fact, that their flying mechanism folds onto their back and is tucked away so that the bird can temporarily function as a land animal. A pterosaur or bat on the other hand is so specialized against gravity -- its anatomy completely given over to the flight mechanism already -- that an increase in gravity would be more likely to ground it for good. And in the case of the pterosaurs, I say it did. Like a heavily-sponsored race car that can't fit one more decal on its frame, there was no room for further adaptation; the pterosaurs' flight technology was mature.


I appreciate the more-specific argument that a lower-G atmosphere would be less dense. As you said, the atmosphere was more oxygen-rich. However, Oxygen is heavier than the other abundant gas in the atmosphere: nitrogen. I conceded earlier that the change in ratios itself does not imply gravitational definition because the gases do not achieve escape velocity; only hydrogen in the outermost layer does that. But, the effect of reduced air pressure would be offset by the change in ratios.

Have paleoentomologists determined that the large size of ancient insects, with their greater ratio of body volume to body surface area, with their trachael respiratory tubes that reach every cell of their bodies like capillaries, allowing for their slower, open circulatory systems to forego the role of gas transport... that their larger size was only possible due to a denser atmosphere? I hadn't heard that, so by all means provide a or periodical reference for me to check out.


You know, you are free to personally consider my ideas however you like. I do not log onto this site with the intent to confuse anybody. I will read further into the relevant areas of science as my work schedule allows, and as my family emergency is hopefully resolved in the next couple of weeks. But as a working man with big stuff going on, I think I'm doing all right as far as maintaining an intelligent discussion here. I may not get the chance to reply quickly, but I'll reply when I can. And like other things in my life, I believe what I'm doing and saying, and not asking others to consider something that I believe in my heart is bogus. In other words, I'm not blowing smoke like Kevin Tredeau (sp?) just to make a name for myself.

My point of view is investigative, but investigation requires time that I don't have right this minute. Until I can, I will argue what I find to be arguable. The overall assumption that any groundbreaking new idea can only come from someone with a big degree and a government paycheck... I don't consider that valid.

Well, I checked out gwangivalley's blog...

http://www.gwangivalley.com/2008/02/23/run-rex-run/

and first off I would like to say I've been looking to have one of those and by golly, now I know where to go so I can have one. Wordpress.org, huh? Very cool.

What kind of traffic do you get on that thing? How do you promote it?

I have some specific counter-arguments all right, which I will get to in turn, what's the hurry?

Are you like, single?

I thought for sure there would be an argument for the lower gravity of the earth, as was proposed by the theorists of the expanding earth. At one time, it was proposed, the earth was smaller in diameter, and the gravity was correspondingly less. The expansion is blamed on sudden appearance of mass as created by fusion taking place in the planets core. This in turn is related to gravity being a form of influx from space of an "aether"/ether. Lots of work on this was developed by Ott C. Hilgenberg. These expansion periods were supposedly quite sudden, and with concomitant shrinking or "falling back", exactly the way plants grow. So goes the theory. Hilgenberg's model included much original work on plate techtonics, for which he gets little credit, and his ether theory also was used to develop a periodic table with elements up into the 200s. His method of developing atomic models presaged the stick-and-ball format, and was predictive, but just how successfully predictive, I can't say. However, his model was capable of being visualized, and he also gave some pretty interesting suggestions as to why the Michaelson-Morely experiment failed to show any relative motion of a "medium", since it was orientated entirely in the horizontal. His suggestion that a vertical component of the apparatus would have shown a significant differential. It is possible to assume that the "extinction" event that is currently attributed to a massive object impacting the earth was due to an expansion event, and that any impact of any object followed this, rather than precipitated it. Since the gravity was suddenly increased while the orb expanded, any object in space affected to move out of a stable orbit would now be attracted. It would also be possible to assume as the shell of the earth was fractured by expansion, more massive areas might slip much more quickly, or plate-movement would be accelerated, and this could explain a lot about discoveries of masses of living forms being collected together as if they had been in a blender. Velikovsky (sp?) gives many references to findings of tons of bones and flesh gathered together in niches in the mantle that are generally attributed to floods or what-not (and he attributed to the near-passage of a planet). Just another alternative theory impossible to test, but possible to apply to further speculations. There are so many different ways to fit the competing theories together, yet the urge to be absolutist about these individual theories defeats each one in many ways which might make sense if the different components were applied together with varying degrees of values corrected for time and allowing for change in gravity values. Most theory assumes gravity constant, with no rational rejection hypothesis. Interestingly, Hilgenberg's theories also provide for reasons to believe the speed-of-light constant has to be rejected as a "locality prejudice" since we can't be sure what the speed of light is outside the environs in which we measure it, that is, in a cosmic or galactic sense.

Hello, Fabrosaur.

I have to say that your response 1. is a bit troubling as there's both no evidence to suggest such a thing and no reason to assume this was the case evolutionarily. You're asking to 'solve' a problem that doesn't exist. Selective pressures to grow large surely existed, because the animal grew larger, but there's no evidence to support the notion that gravity increase was among those pressures. Queztlcoatlus' wing area to mass ratio is much less favourable than its smaller, earlier brethren such as Thalassodromeus or Tupuxuara (A good chart to do the math from can be found in - Humphries S, Bonser RHC, Witton MP, Martill DM (2007) Did Pterosaurs Feed by Skimming? Physical Modelling and Anatomical Evaluation of an Unusual Feeding Method. PLoS Biol 5(8): e204 doi:10.1371/journal.pbio.0050204).

This sort of falls smack into point 2. Circumstantial evidence, of which I see very little, cannot hope to contend with physical, experimental and observational evidence in a fair fight.
Unless this circumstantial evidence is packing a knife. It had also best bring a pickaxe to break up and hide the sedimentary evidence which flows evenly and as expected in the geological record and never indicates this gravity difference.

And, I have to be frank, it's not up to me to 'falsify' lower paleogravity, it's up to you lot to falsify the evidence to the contrary as the case for this alternative theory is light enough to take flight in even the thin atmosphere we keep coming back to. Yet evidence against it is rather... weighty (no gravity pun intended).
The preponderance is upon you.
Extraordinary claims require extraordinary evidence.
When one claims that gravity change may have played a role in dinosaur extinction, one must being by answering the challenge of the scientific record which does not indicate anything of the sort took place.

And, forgive me... but what _is_ you boys' fascination with gigantism? LOL
Sure, there were giant things then and there are giant things now. There seems to be some notion that gigantism is an evolutionary goal. Every niche is not a large hole. But if one takes a 2 foot wingspan dragonfly-like insect and sticks it into our atmosphere, it will not survive. That's a point of a very fine nature. (as Dinotheorist rightly asks me to cite more in his response, I'm doing so here as well. See this story and associated papers which show recent studies bearing this out: http://www.sciencedaily.com/releases/2006/...61012093716.htm ). We know with a great degree of certainty the atmospheric makeup in question and there was definitely a higher oxygen concentration that allowed these insect to live (without the aid of respirators or oxygen tents). We also know how gases of a planetary body behave under different gravitational influences.

Lowering the gravity for the Mesozoic or the Cambrian would have a marked change on the Earth model and the inhabitants as observed. It would require us to set aside good evidence and say "that has to be wrong in order for this other theory to remain viable." And then we'd have to go change our climate models. The K-T event would need to look very different. We had an entire continent undergoing extreme volcanism AND miles away a large meteoric impact ... and now we need to lower the gravity too? What does this do to the Permian extinction with its even lower gravity? Sorry... it's like coming up to a sheer-faced cliff and saying "I have a notion that it might be thin as paper" while beside you someone's extracting a core samples doing comparative analysis.

I appreciate you responding and I hope things work out OK vis-à-vis the family.



Well.. I have a particular bent about this issue and you come up highly enough in Google that I really felt compelled to come have a chat. In case you're wondering why I've singled you out.



Well, we can agree on the above just fine.
Unless, of course, you're saying you intend to cling to that 'too heavy' belief to insulate your hypothesis despite the evidence you admit has been accumulated to the contrary.
It is still a false premise (you state as much in those last two lines).



I... cannot agree with your first statement. Within the framework of science one builds upon 'best evidence'. One does not have the luxury of working in a vacuum and then filling in around ones hypothesis, one must acknowledge, include and account for the evidences which have come before you. And, at the same time, one must push the boundaries to make sure the walls of some accepted notion do not cave in easily. There is an accepted model of Earth gravity. It is tested every day in any number of disciplines. It is part of our larger model of natural history. Scientists are finding evidence about dinosaurs and early Earth history which do not challenge that model nor suggest problems with it (again further substantiating it).

The 'question of lower gravity' has not shown itself to have merit. There's no conspiracy to ignore the idea, but there's no impetus to favour it. It is no longer considered because the evidence is to the contrary. You really would be asking that large chunks of good science be tossed aside just to reconsider the idea. And without some compelling evidence to defend such a pleading... why would anyone join the cause? It's like asking someone to abandon germ theory, setting aside all the evidence showing it to be true, because you really think there might be something to the miasmatic theory. No one's likely to jump on the bandwagon.



I think you'd be surprised how little your pedigree matters when you've made a profound finding. A bust of Nicola Tesla, a man whose bouts with education were troubled, brief and unfinished, sits in the library of Harvard University's physics department. Here is a man revered in a institute of higher learning so much that he is the only person whose face graces that library, yet he never finished a degree or held a doctoral title.

I hope you don't think I'm trying to shut you up. Neal Adams, yes. He needs to shut up because he's crazy. You, you seem like someone genuinely passionate about discovery. But, I feel, you're missing some pieces of this puzzle which has caught you up so eagerly. You've gone down a garden path that's overgrown for a reason. And you may be leading others down it precisely because you are a bright mind set on a spark (instead of a crazy little egomaniac or a delusional). That is what concerns me.



You do love your Bakker. I'm half-tempted to send you some new books. _grin_ Perhaps you'd be more of a John Hutchinson man, if we put Bakker on the table for a while. A lot has happened in the 20 years since Bakker's book. But, by the way, in that time it's still argued whether or not Diplodocus stood on its hind legs. And, again, why this push towards gigantism? You're attempting to reinvent Foster and Case and 'generations of educated men' whose research has withstood scrutiny. There are many factors which influence organism size and chief among them is the amount of energy an organism can take in for a given period. This is why your crocodiles don't grow into monsters. They're quite in balance with their place in the natural world. And a hyperoxic atmosphere can increase gigantism and did so in ages including the Paleozoic and Carboniferous (until the hypoxic crash of the Permian put a stop to it). (see Robert Dudley - The Journal of Experimental Biology 201. See also Kasier, Quinlan, et al. - No giants today...)

But... I need to understand something here. Are you saying that the gravitational increases were punctuated and not gradual/sloped? That the increases came in fits and spurts? (and do you have relative percentages of decrease in gravity? i.e. - at x million years gravity was x% of 1G.)

Also... Yes. The trees. Have you considered the trees, by the way? How they would behave in the Cambrian? Mesozoic? Permian? Carboniferus? and on as gravity supposedly increased? Just curious if you've thought about this.



I think you're quibbling with the whole 'adapted versus specialized'. Both animals flew/fly and walk/walked. See:

Posture, Locomotion, and Paleoecology of Pterosaurs - Sankar Chatterjee and R.J. Templin - Geological Society of America (ISBN 0-8137-2376-0)

In brief: Pterosaurs flew pretty well in the traditional sense (all calculations and derivations weighted in a 1G world), except for the very largest which still appear to have been rather good gliders,. They could also morph their wing shape.

Adaptation and specialization.



Density is a function of pressure and volume. Lower gravity, lower pressure, less density. Bug's gotta take in more air to get enough oxygen out of it. Bug's also got to work harder to fly.



Again, I hope things at home work out well and soon. And I would like to reiterate that I don't consider you a quack. I think there are gaps in your knowledge that are allowing you to fall into holes which don't have to be.



Recall what I said about Tesla. I am not making that argument. But, I will argue for the superiority of data. And those with access to the resources to investigate will necessarily produce superior data. Especially in the modern world we live in where that data is then passed on to others to peer at and poke and rip apart if they can, or acknowledge as strong when they cannot. And much of that same data is available to you, for you to weigh and consider. (hehe But please, put the Bakker down for now.) I would urge you to look into the work of Chatterjee and also Hutchinson to fill in the potholes.

Ella

PS - No, I'm not single. Sorry. And as for my blog, I do indeed host it using Wordpress software (but one could also use blogger or the like instead of hosting it yourself - I just do so because it works best for me). I don't actively promote the site, per se, but it gets enough traffic to keep me doing it (I blog elsewhere as well, but this site allows me freedoms I don't otherwise have. I stopped blogging at another site once I decided to do gwangivalley.com, and as you can see it hasn't been there very long.)

Response to guangivalley


When the impact theory of extinction was introduced there were many who opposed it. Many of those people had their careers damaged, funding for their research grants dried up and they were denigrated because they did not jump on the impact bandwagon. Those that have written books and articles supporting the impact theory