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388 years ago, Galileo worked out why human giants can't exist

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Re: 388 years ago, Galileo worked out why human giants can't exist

#51

Post by timedude »

Lumich wrote: post #46
kergonath wrote: post #39

Earlier quoted context omitted.

What do you mean? The Earth does not "grow" and is not really bigger now than at any point in the past (since the creation of the Moon). On the contrary, it is losing mass through the escape of light atoms escaping, but even that is absolutely tiny. Also, the Earth is absolutely not a living organism.

What he means is probably the idea of Earth Expansion . See Ott Christoph Hilgenberg, a disciple of Alfred Wegener, and more recently (but still a couple decades ago) Australian geologist Samuel Warren Carey. Here's a 1982 video featuring him on the topic of “Planet Earth: A Question of Expansion”: https://youtu.be/Othb0xsvZb4 – 26 minutes This view is kinda ostracized in geology and considered heresy.

It is growth and not simply expansion. All planets grow and are living organisms. This was common knowledge for the ancients. Carl Sagan made a similar remark once

Re: 388 years ago, Galileo worked out why human giants can't exist

#52

Post by timedude »

Lumich wrote: post #46
kergonath wrote: post #39

Earlier quoted context omitted.

What do you mean? The Earth does not "grow" and is not really bigger now than at any point in the past (since the creation of the Moon). On the contrary, it is losing mass through the escape of light atoms escaping, but even that is absolutely tiny. Also, the Earth is absolutely not a living organism.

What he means is probably the idea of Earth Expansion . See Ott Christoph Hilgenberg, a disciple of Alfred Wegener, and more recently (but still a couple decades ago) Australian geologist Samuel Warren Carey. Here's a 1982 video featuring him on the topic of “Planet Earth: A Question of Expansion”: https://youtu.be/Othb0xsvZb4 – 26 minutes This view is kinda ostracized in geology and considered heresy.

https://m.youtube.com/watch?v=7kL7qDeI05U

Re: 388 years ago, Galileo worked out why human giants can't exist

#53

Post by necovek »

ndr wrote: post #30
necovek wrote: post #16

Earlier quoted context omitted.

Regarding 1, horses in particular are known to jump off two hind legs and land on their two forelegs, putting a lot more force on them than their stationary weight. On 2, I believe that's the GP's point too — human leg bones (or horses') can obviously take a lot more than their standing/walking/running weight.

Agree re 1, but point 2 still stands. They can take more stress than standing, but the scaling law is still there. If you scale linearly height/section the max stress won't scale linearly because the weight will scale cubically.

As I mentioned elsewhere, eg. femur can take at least 30x body weight, and we've got two to carry us. If a giant is 10x the size, and femur is just scaled linearly, even with 10x the relative weight, it can still take 3x giant's body weight. So perhaps no jumping on one leg anymore, but walking or light jogging should be fine.

But, their bones could also have larger cross-section and a giant could be stockier yet still appear "human like".

Re: 388 years ago, Galileo worked out why human giants can't exist

#54

Post by stevenwoo »

Lumich wrote: post #49
stevenwoo wrote: post #12

Earlier quoted context omitted.

They were larger but not as dense as mammals, we know had adaptations like less denser bones and different respiratory systems that allow for more efficiency and much more rapid growth into maturity. Modern birds show evidence of all these traits. When the Chicxulub extinction event happened it reset things so mammals got the upper hand on large sizes and eventully won out for the most part. Highly recommend The Rise…

« Highly recommend The Rise and Fall of Dinosaurs » (by Steve Brusatte) This book fails to mention both Gideon Mantell (1790–1852) and Richard Owen (1804–92). It's through them that dinosaurs entered our modern, scientific world.

I don’t have good recollection of names of early scientists he notes but I think he discusses many of them if not in this work but also in either The Story of Birds or The Rise and Reign of Mammals. I read all three in quick succession so it’s mildly blurred in my brain. It’s pop science so I’m not expecting comprehensive overview but the most up to date science as of date of publication.

Re: 388 years ago, Galileo worked out why human giants can't exist

#55

Post by stevenwoo »

adrian_b wrote: post #22
stevenwoo wrote: post #12

Earlier quoted context omitted.

They were larger but not as dense as mammals, we know had adaptations like less denser bones and different respiratory systems that allow for more efficiency and much more rapid growth into maturity. Modern birds show evidence of all these traits. When the Chicxulub extinction event happened it reset things so mammals got the upper hand on large sizes and eventully won out for the most part. Highly recommend The Rise…

You are right that they had pneumatic bones and air sacs and they were not as heavy as mammals with the same volume would have been. Nonetheless, the biggest dinosaurs were several times heavier than the heaviest terrestrial mammals that have ever lived, which in turn were several times heavier than the biggest elephants of today. So probably dinosaurs were close to the size limit that is imposed by the mechanical pr…

For those interested, I think many of these issues are discussed (but not in the particular way we are) in the trilogy of books starting with the Rise and Fall of Dinosaurs, continuing with The Story of Birds and the Rise and Reign of Mammals.

Re: 388 years ago, Galileo worked out why human giants can't exist

#56

Post by kergonath »

Lumich wrote: post #46
kergonath wrote: post #39

Earlier quoted context omitted.

What do you mean? The Earth does not "grow" and is not really bigger now than at any point in the past (since the creation of the Moon). On the contrary, it is losing mass through the escape of light atoms escaping, but even that is absolutely tiny. Also, the Earth is absolutely not a living organism.

What he means is probably the idea of Earth Expansion . See Ott Christoph Hilgenberg, a disciple of Alfred Wegener, and more recently (but still a couple decades ago) Australian geologist Samuel Warren Carey. Here's a 1982 video featuring him on the topic of “Planet Earth: A Question of Expansion”: https://youtu.be/Othb0xsvZb4 – 26 minutes This view is kinda ostracized in geology and considered heresy.

> What he means is probably the idea of Earth Expansion.

No, it’s probably not what they meant, because otherwise that would be completely inconsistent with the bit about "increased gravity" (whatever that mean).

It’s also wrong. Less wrong than Earth being a living organism, but still quite wrong.

> This view is kinda ostracized in geology and considered heresy.

I know this is a figure of speech, but this is not the right metaphor at all for how science works.

Re: 388 years ago, Galileo worked out why human giants can't exist

#57

Post by boxed »

adrian_b wrote: post #33
boxed wrote: post #8

Earlier quoted context omitted.

That seems to not be the reason from the latest data. Insect oxygen transfer basically doesn't scale cleanly with oxygen in the atmosphere like the original hypothesis thought. What IS true though is that pterosaurs and later birds and bats came onto the scene, and that's just game over for giant dragonflies.

Vertebrates have 2 essential advantages over insects, at big enough sizes. An efficient circulatory system and myelinated nerves. At small sizes, the circulatory and respiratory systems of insects work better (less friction for blood in the absence of capillaries and less friction for the air that circulates as a gas through the body), but at big sizes those of vertebrates work better, due to efficient pumping. The m…

Exo- vs endoskeleton has some big consequences too.

Re: 388 years ago, Galileo worked out why human giants can't exist

#58

Post by Lumich »

kergonath wrote: post #56
Lumich wrote: post #46

Earlier quoted context omitted.

What he means is probably the idea of Earth Expansion . See Ott Christoph Hilgenberg, a disciple of Alfred Wegener, and more recently (but still a couple decades ago) Australian geologist Samuel Warren Carey. Here's a 1982 video featuring him on the topic of “Planet Earth: A Question of Expansion”: https://youtu.be/Othb0xsvZb4 – 26 minutes This view is kinda ostracized in geology and considered heresy.

> What he means is probably the idea of Earth Expansion. No, it’s probably not what they meant, because otherwise that would be completely inconsistent with the bit about "increased gravity" (whatever that mean). It’s also wrong. Less wrong than Earth being a living organism, but still quite wrong. > This view is kinda ostracized in geology and considered heresy. I know this is a figure of speech, but this is not the…

« probably not what they meant » – Right, he implied Earth is a “living organism”, which is an additional proposition on top of expansion. (Who knows, maybe it is.) The bit about “increased gravity” could mean that Earth may have gained mass (via some as yet unknown mechanism) at some point of her history, something Carey touches upon in the video I linked.

I wonder how people can be so certain that Earth first accreted from "constructive" collisions out of some dust cloud, but then, once her "correct" size attained (in accordance with "Laws of Nature"), did not suffer any further changes in size or mass, except for infinitesimal ± due to hydrogen escaping or collecting shooting stars. After all, there is zero direct evidence for that story/theory, just as the interior of the Earth continues to be empirically unknown to us beyond a depth of about 12 km.

What I think is that the idea of an expanding/growing Earth (“gotten drastically bigger” at some point in the not so distant geological past, a development which cannot be observed in the present) does not fit the overall science story (physics/cosmology, mass/matter/gravity) and hence is rejected despite the geological surface evidence (see Carey video).

Re: 388 years ago, Galileo worked out why human giants can't exist

#59

Post by Lumich »

kergonath wrote: post #56
Lumich wrote: post #46

Earlier quoted context omitted.

What he means is probably the idea of Earth Expansion . See Ott Christoph Hilgenberg, a disciple of Alfred Wegener, and more recently (but still a couple decades ago) Australian geologist Samuel Warren Carey. Here's a 1982 video featuring him on the topic of “Planet Earth: A Question of Expansion”: https://youtu.be/Othb0xsvZb4 – 26 minutes This view is kinda ostracized in geology and considered heresy.

> What he means is probably the idea of Earth Expansion. No, it’s probably not what they meant, because otherwise that would be completely inconsistent with the bit about "increased gravity" (whatever that mean). It’s also wrong. Less wrong than Earth being a living organism, but still quite wrong. > This view is kinda ostracized in geology and considered heresy. I know this is a figure of speech, but this is not the…

« how science works » – It's a human activity and as such it not only bears all the hallmarks of human behaviour (certainly filtered/tempered, yes) but is also subject to overarching "ideological" issues that govern society, all the more so as its material/social existence is usually institutionalized and tied to things like salary, reputation and careers.

I've seen evidence of scientists behaving in ways that warrant just the terms I used, ostracism and heresy, when "dealing with" someone questioning/attacking "core tenets" (which, if successful, perhaps after decades, can lead to a "paradigm shift", like "continental drift").

That's not to say all scientists behave alike, of course; psychologically and statistically, average human behaviour should be expected, which typically means conformist and aligned behaviour (civility/restraint, but also "don't upset the applecart").

Re: 388 years ago, Galileo worked out why human giants can't exist

#60

Post by Lumich »

timedude wrote: post #52
Lumich wrote: post #46

Earlier quoted context omitted.

What he means is probably the idea of Earth Expansion . See Ott Christoph Hilgenberg, a disciple of Alfred Wegener, and more recently (but still a couple decades ago) Australian geologist Samuel Warren Carey. Here's a 1982 video featuring him on the topic of “Planet Earth: A Question of Expansion”: https://youtu.be/Othb0xsvZb4 – 26 minutes This view is kinda ostracized in geology and considered heresy.

https://m.youtube.com/watch?v=7kL7qDeI05U

This video is by graphics artist Neal Adams (who I just learnt passed away in 2022). He had a whole series of these videos on his Youtube. I was fascinated when I discovered them ~2008. He was passionate about Earth Expansion. But despite the assertive tone of the voice and the triumphant music, it cannot be properly seen in this sketchy representation how exactly the continents were supposed to fit together on a smaller globe. And the artistic approach he chose suggests that he cared more about the general idea and vision than about the details, which of course is perfectly legit for an artist.
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