Dinosaurs And The Gravity Problem (by Ted Holden)

[John]

I was going to post my issues with the article but I think this site says it all http://www.talkorigins.org/faqs/homs/holden.html

Now not offense to the religious types but this guy is a loony.

Yes, he's the crackpot that claims his Pennsylvanian age coal balls and concretions are human remains. He's about as far out on the edge of nuttery as they get.

[Cris]

Let's not forget that the largest animal of all time isn't a dinosaur -- it's the living Blue Whale. The Blue Whale is larger than any dinosaur that ever existed and it is even bigger than any marine reptile of the dinosaur era.

Good post. Almost exactly what I thought when I heard that "animals never experimented with gigantism".

By the way, welcome to the Forum John.

[Guest solius symbiosus]

Yes, he's the crackpot that claims his Pennsylvanian age coal balls and concretions are human remains. He's about as far out on the edge of nuttery as they get.

Welcome! It is always nice to see another skeptic on the forum. Too, it is a testament to your fortitude that you managed to read the article. When I see some of those "key words" in wack-a-loon literature, I just roll my eyes, and close the page... it ain't worth it.

EDIT: Oooh, re the article:

[lordpiney]

thats why i posted the article in the first place! just so everyone could get a chuckle. i hope i didnt offend anyone by the utter stupidity of, and the overall long size of it. i promise i'll keep things shorter from now on.

[siteseer]

The article is pure crackpot science. Let's not forget that the largest animal of all time isn't a dinosaur -- it's the living Blue Whale. The Blue Whale is larger than any dinosaur that ever existed and it is even bigger than any marine reptile of the dinosaur era. By the author's "logic", shouldn't that mean that gravity on Earth must have actually been STRONGER in the past? Also, if any kind of external force (or lack thereof) caused vertebrate gigantism in the Mesozoic, why weren't there marine reptiles bigger than the Blue Whale?

It's also instructive to point out that the whole of the Cenozoic is just a fraction of the time dinosaurs lived on Earth. For nearly their first 100 million years the dinosaurs themselves were no bigger than the bigger mammals that exist today. The real giants aren't found until the late Jurassic, so gigantism in the dinosauria took from the Middle Triassic to the Late Jurassic to happen.

Even worse, the idea that Pangea was somehow "pulled together" by an oddity of gravity from the sun or anywhere else is just ridiculous. As most of us know, Pangea was the result of plate tectonics, a process that is easily observable and which needs no mysterious violations of physics to accomplish.

It's pretty clear that the author has only a weak grasp of everything from paleontology to high school physics and mixes them into a mish-mash of crackpottery that cherry picks facts to substantiate a claim that's so easy to disprove.

Yeah, it's the paleo version of astrology.

Uh-oh, I think we have an actual paleontologist among us. He knows about Mazon Creek stuff, dinosaurs, and plate tectonics. That narrows him down to just a few people in California. Welcome to the forum, John.

[Mike_H]

The article is pure crackpot science. Let's not forget that the largest animal of all time isn't a dinosaur -- it's the living Blue Whale. The Blue Whale is larger than any dinosaur that ever existed and it is even bigger than any marine reptile of the dinosaur era. By the author's "logic", shouldn't that mean that gravity on Earth must have actually been STRONGER in the past? Also, if any kind of external force (or lack thereof) caused vertebrate gigantism in the Mesozoic, why weren't there marine reptiles bigger than the Blue Whale?

It's also instructive to point out that the whole of the Cenozoic is just a fraction of the time dinosaurs lived on Earth. For nearly their first 100 million years the dinosaurs themselves were no bigger than the bigger mammals that exist today. The real giants aren't found until the late Jurassic, so gigantism in the dinosauria took from the Middle Triassic to the Late Jurassic to happen.

Even worse, the idea that Pangea was somehow "pulled together" by an oddity of gravity from the sun or anywhere else is just ridiculous. As most of us know, Pangea was the result of plate tectonics, a process that is easily observable and which needs no mysterious violations of physics to accomplish.

It's pretty clear that the author has only a weak grasp of everything from paleontology to high school physics and mixes them into a mish-mash of crackpottery that cherry picks facts to substantiate a claim that's so easy to disprove.

Yeah, it's the paleo version of astrology.

Unfortunately the Blue Whale arguement doesn't hold up. They are aquatic animals thus water holds up that bulk and allows them to get huges. But I do agree with the rest of your points.

[siteseer]

Unfortunately the Blue Whale arguement doesn't hold up. They are aquatic animals thus water holds up that bulk and allows them to get huges. But I do agree with the rest of your points.

At some point a blue whale's buoyancy could not offset a gravitational force greater than that which exists today. Any marine animal that needs to surface to breathe would feel the difference as they would have to exert themselves more just to swim level and even more to surface. Plankton-feeding might not be nutritious enough to support the extra constantly-required energy expenditure. Many whales might be pushed to extinction in that event.

[32fordboy]

Unfortunately the Blue Whale arguement doesn't hold up. They are aquatic animals thus water holds up that bulk and allows them to get huges. But I do agree with the rest of your points.

I agree with this one. I figure an aquatic animal can grow MUCH larger than a land animal partly because they are supported by the water, requiring less bone mass per pound, eliminating whales from this debate. This goes back to my original statment about how paraceratherium was pretty close to the maximum size for a land mammal based on bones structure, whereas larger sauropods had a different bone structure that could support a much larger weight. In my opinion, the only things that would affect size are: oxygen levels, bone structure, and skeletal support (wheather it be water or muscle). I hope that all makes sense-I'm no scientist.

[Mike_H]

I agree with this one. I figure an aquatic animal can grow MUCH larger than a land animal partly because they are supported by the water, requiring less bone mass per pound, eliminating whales from this debate. This goes back to my original statment about how paraceratherium was pretty close to the maximum size for a land mammal based on bones structure, whereas larger sauropods had a different bone structure that could support a much larger weight. In my opinion, the only things that would affect size are: oxygen levels, bone structure, and skeletal support (wheather it be water or muscle). I hope that all makes sense-I'm no scientist.

Exactly, 32fordboy.

siteseer, not totally true. Considering the volume of water on the planet and the whale's mass, more than enough water is displaced to keep the animal boyant. And we know how they can dive and surface through their lungs. Yes, their mass would cause them to sink but that is also why they are instantly moving.

It's not the gravitaional pull they would experiance but preasure. But that is one reason why they could have gotten so large. True that mauy be countered with the deep sea fish such as the angler but they evolved in the depths, whales did not. It is evident that large size in deep diving mammals is required. For example the sperm whale, they dive to depths than all other mammals cannot save for humans in a sub, even then that's risky.

As 32fordboy said, "oxygen levels, bone structure, and skeletal support (wheather it be water or muscle)."

So the whale aguement still does not hold "water" so to speak.

[Auspex]

At some point a blue whale's buoyancy could not offset a gravitational force greater than that which exists today. Any marine animal that needs to surface to breathe would feel the difference as they would have to exert themselves more just to swim level and even more to surface. Plankton-feeding might not be nutritious enough to support the extra constantly-required energy expenditure. Many whales might be pushed to extinction in that event.

Positive buoyancy only requires that the item in question weigh less than the volume of water it displaces. If we accept for the moment the preposterous idea of variable gravity, the weight of the displaced water would be effected too: the whale would be just as buoyant. The pressures would increase logarithmically with depth, however, and would certainly restrict the animal's dive depth.

[32fordboy]

I must add here: I absolutely love these threads! Gets the brain goin.

Nick

[John]

Good post. Almost exactly what I thought when I heard that "animals never experimented with gigantism".

By the way, welcome to the Forum John.

Thanks!

[John]

I agree with this one. I figure an aquatic animal can grow MUCH larger than a land animal partly because they are supported by the water, requiring less bone mass per pound, eliminating whales from this debate. This goes back to my original statment about how paraceratherium was pretty close to the maximum size for a land mammal based on bones structure, whereas larger sauropods had a different bone structure that could support a much larger weight. In my opinion, the only things that would affect size are: oxygen levels, bone structure, and skeletal support (wheather it be water or muscle). I hope that all makes sense-I'm no scientist.

Unfortunately, buoyancy is irrelevant here because, as I pointed out, there are no Mesozoic marine reptiles (or anything else in the ocean at the time) that rival the Blue Whale in size. If Holden's (?) claim were correct, why didn't the "weaker gravity" cause marine reptiles to grow at least to the size of Blue Whales, or even bigger?

It's also worth mentioning that sauropods do NOT have different bone structure from mammals, they have a different skeletal morphology. All higher vertebrate bone has the same tensile strength and structural properties. Reptilian and mammalian muscles are different, but the bones they attach to have the same physio-chemical properties.

[32fordboy]

Okay, I see what you're getting at with the marine reptiles. We were simply ignoring the fact that whales get larger than dinos (because of water support) for the sake of argument. As far as the bone structure, it might be the same on a microscopic level, but I've not seen too many dino bones that were built the same as mammal bones. From what I've read they are built very differently, but then again-I'm no scientist .

Nick

[fig rocks]

I think this answers all the questions in regard to the buoyancy issue.

[Mike_H]

There were marine reptiles that big, Liopleurodon. 82ft roughly in length. And dinosuars got bigger than the blue whale, Seismosaurs is thought to get 120+ feet long and about 100 tons. So, still, that arguement doesn't stand.

I'd like to see what you say about giant squid. I mean the lagest is about the same mass as a large whale.

[tracer]

i'm glad cats don't build card houses. if we had thumbs, ya'll be in deep doo-doo, no matter how much you weighed.

tc

p.s. - my bone structure's better than yours.

[Theorist]

Hello,

This is my first post and I'd like to join the discussion on Dinosaurs And The Gravity Problem.

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.

[siteseer]

Hello,

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.

Theorist,

At the end of the Jurassic there was a significant extinction event among the dinosaur groups, nearly wiping them out. An evolutionary restart in the Early Cretaceous allowed new groups or previously-uncommon groups to prosper. Groups such as the ankylosaurs, ceratopsians, pachycephalosaurs, hadrosaurs, and tyrannosaurs (plus therizinosaurs and ornithomimds) increased in size during the Late Cretaceous with the largest representatives living in the last five million years of it. The largest pterosaur (perhaps twice the size of Pteranodon which lived not long before it and which was also a big animal) also lived near the end of the Cretaceous. If gravity was somehow increasing across the Cretaceous, it would seem unlikely that dinosaur size would be on the upswing among so many (if any) groups during the same interval.

[Mike_H]

I would like to remind folks that we cannot really compare dinosaurs and giant reptiles of the mesazoic with mammals today. They were simply so vastly differant animals.

But if we must, 45 millian years ago, there was a carniverous whale that exceeded 100ft long.

I'm sorry but I do not buy the "variable gravity" theory. The earth's gravity is constant, there is nothing the prove otherwise in physics. The planet is revolving at a constant rate thanks to the moon's gravitational pull. Nothing has changed that as far as I know. It's just a matter of being built for large size.

Dinosaurs just grew very large because the evolved adaptations that could deal with it. Not to mention the numerous smaller species. Which many conveniently forget about when discussing dinosaur size.

Besides, why are we even discussing this crackpot theory by this crackpot pseudoscientist anyway?

[32fordboy]

'Cause it's fun!

[Auspex]

...The basic premise that gravity was less during the reign of the dinosaurs......I do agree with....

Can you cite the physics behind such a massive gravity anomaly?

[32fordboy]

Now that I think about it, and don't quote me on this, but I remember reading, probably in Astronomy Magazine that the Earth's rotation was faster back then, resulting in 18 hour days. Could the spinning force counteract more of the Earth's gravity? So gravity would really be the same, but an opposite force (from the faster spin) would make gravity appear to be weaker???????? That plus the moon was closer to Earth (I have no ideas what the implications of this might be). Hmmmmmm. Oh boy. I feel I'm digging a hole and I am all for constant gravity.

Nick

Edited September 10, 2009 by 32fordboy

[siteseer]

Now that I think about it, and don't quote me on this, but I remember reading, probably in Astronomy Magazine that the Earth's rotation was faster back then, resulting in 18 hour days. Could the spinning force counteract more of the Earth's gravity? So gravity would really be the same, but an opposite force (from the faster spin) would make gravity appear to be weaker???????? That plus the moon was closer to Earth (I have no ideas what the implications of this might be). Hmmmmmm. Oh boy. I feel I'm digging a hole and I am all for constant gravity.

Nick

Yes, the earth has been slowing its rotation but it's been by about three hours since the Silurian. That was in one of my geology texts over twenty years ago.

Yeah, you're right, it's fun.

[32fordboy]

hmm very interesting.