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https://www.researchgate.net/publication/26553081_Atmospheric_pressure_at_the_time_of_dinosaurs https://www.researchgate.net/publication/26553081_Atmospheri...

feoren 5y ago
I'm not great at evaluating the quality of Journals (Chemical Industry and Chemical Engineering Quarterly is at least peer reviewed), but that article has been cited 0 times, and its abstract reads like a YouTube video trying to convince me Bush did 9/11. > how can a giant dinosaur such as an apatosaur pump blood up to its brain (more than 13 m above its heart) when animal energetics and physics say that in no way can it do it. Do we have to change the laws of physics and biology? I don’t think so. The "Science says it's impossible! Either we have to change the laws of science, or <my one pet alternative theory out of 10 million other alternatives> must be true!" is just really characteristic of that style.
- robbedpeter 5y ago
  We don't have soft tissue or a specific understanding of internal organs. Maybe they had multiple hearts with multiple vascular systems, or maybe the rate of blood flow and chemistry of energy production differed from animals we do understand. All we know for sure is that the brontosaurus was way too big for its biology to be understood by similarity to any extant creatures. Maybe we'll be able to simulate dna, protein, and evolution at some point such that we can sample huge spaces to see if we can reconstruct creatures with similar features.
zardo 5y ago
Just skimming for what I was interested in, I don't see anything to suggest that a thicker atmosphere would provide support for a large land animal. That would require structures in the animal kept at below ambient pressure. e.g. heated air sacs
- lazide 5y ago
  Also basic density calculations doesn’t favor the theory. Even at 100bar, even with some weird composition difference (but not completely bizarre like sulphur hexaflouride) the atmosphere is on the order of 10-20kg/m^3. Even with the most implausible ‘what a dinosaur is made of’ theories I can come up with, unless the larger dinosaurs were born carrying around 100+ m^3 balloons full of helium, it doesn’t seem doable. There literally isn’t enough space in them to have enough sacs of lighter than air gas for that to make sense.

feoren 5y ago

I'm not great at evaluating the quality of Journals (Chemical Industry and Chemical Engineering Quarterly is at least peer reviewed), but that article has been cited 0 times, and its abstract reads like a YouTube video trying to convince me Bush did 9/11. > how can a giant dinosaur such as an apatosaur pump blood up to its brain (more than 13 m above its heart) when animal energetics and physics say that in no way can it do it. Do we have to change the laws of physics and biology? I don’t think so. The "Science says it's impossible! Either we have to change the laws of science, or <my one pet alternative theory out of 10 million other alternatives> must be true!" is just really characteristic of that style.

robbedpeter 5y ago
We don't have soft tissue or a specific understanding of internal organs. Maybe they had multiple hearts with multiple vascular systems, or maybe the rate of blood flow and chemistry of energy production differed from animals we do understand. All we know for sure is that the brontosaurus was way too big for its biology to be understood by similarity to any extant creatures. Maybe we'll be able to simulate dna, protein, and evolution at some point such that we can sample huge spaces to see if we can reconstruct creatures with similar features.

zardo 5y ago

Just skimming for what I was interested in, I don't see anything to suggest that a thicker atmosphere would provide support for a large land animal. That would require structures in the animal kept at below ambient pressure. e.g. heated air sacs

lazide 5y ago
Also basic density calculations doesn’t favor the theory. Even at 100bar, even with some weird composition difference (but not completely bizarre like sulphur hexaflouride) the atmosphere is on the order of 10-20kg/m^3. Even with the most implausible ‘what a dinosaur is made of’ theories I can come up with, unless the larger dinosaurs were born carrying around 100+ m^3 balloons full of helium, it doesn’t seem doable. There literally isn’t enough space in them to have enough sacs of lighter than air gas for that to make sense.