388 years ago, Galileo worked out why human giants can't exist(scientificamerican.com) |
388 years ago, Galileo worked out why human giants can't exist(scientificamerican.com) |
https://tvtropes.org/pmwiki/pmwiki.php/Main/SquareCubeLaw
It's the reason why giant robots probably couldn't be as agile or powerful as in something like Transformers or Gundam, and why kaiju like King Kong or Godzilla couldn't exist in the real world.
I'd also note that it does not take a lot for someone to be a "giant". When average height was 1.6m, someone 2.2m tall was certainly a "giant" (they are even today, but it means they'd frequently be asked if they are playing basketball :)).
But even if they were 4m tall, they'd certainly be called a giant and certainly regular human bones could handle weight up to say 450 kg. Heck, someone brought up horses and cows, and horses certainly jump off two hind legs and land on two front ones, putting a lot more than 600kg of their standing weight on them.
So in short, Scientific American is right to bring up the fact that someone like Galileo would put his genius to folk topics back in the day, we do have a bit more to lean on today to come up with even stronger conclusions — so they'd better highlight how his thinking compares to what was known back in the day.
Hopefully no cheese eating space mold gets up there or we're done !
2. That would be assuming that human legs are sized at the max capacity they can carry, which is not true.
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.
The practical limit for bipeds is probably ability to survive a fall to the ground. It's not super common, but enough people die simply from falling from standing.
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Also we know in the past there were dargonflys with wingspans greater than 2 feet and centipedes that grew as long as a car.
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 properties of vertebrate tissues like bones, tendons and muscles, while in the present terrestrial mammals the size is limited by the availability of food and by the humans who have always hunted preferentially the biggest animals they encountered, and not by the strength of their bones.
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.
> scaled-up wooden houses would not support their own roofs
Hmmm this argument fails to mention giraffes, elephants or dinosaurs. Clearly land animals with bones can be quite a bit larger than humans. Similarly the houses comment ignores that large multi-story wooden buildings that support their own roofs exist, and already existed in Galileo’s time.
There might be reasons today’s evolution of human anatomy can’t get any larger than 9 feet tall, but this argument about physics and bones and square vs cube growth rates is pretty unconvincing. The argument skips right past the idea of “giants” that are only 1.5x or 2x or 3x taller, rather than 10x or 100x taller. Sure animals cannot be “inordinately” bigger, but that does not explain why they can’t be twice as big.
True for Scientific American today, not true for Galileo.
“Dinosaur” wasn’t a thing we started knowing about until the early 1800s. Benjamin Franklin died not knowing Dinosaurs were a thing.
But Galileo would have certainly known about elephants though.