500-Year-Old Leonardo Da Vinci Sketches Show Him Grappling With Gravity (gizmodo.com) 32
An anonymous reader quotes a report from Gizmodo: A team of engineers studying the 500-year-old, backward writings of Leonardo da Vinci have found evidence that the Italian polymath was working out gravity a century before its foundations were established by Galileo Galilei. The team's findings come from a revisit of the Codex Arundel, a compilation of documents written by da Vinci that detail various experiments and personal notes taken down in the latter 40 years of his life. The codex is freely accessible online courtesy of the British Museum. The team's research is published in the MIT Press journal Leonardo. Mory Gharib, an engineer at Caltech, said he stumbled across the writings in 2017 when looking for some of da Vinci's work on flow in hearts. Though the codex was written over a long span of da Vinci's later years, Gharib suspects the gravitational musings were written sometime in the last 15-or-so years of his life. Gharib recruited co-author Flavio Noca, a researcher at the University of Applied Sciences and Arts Western Switzerland, to translate the Italian's backward writing on the subject.
Da Vinci understood some fundamentals of objects in motion. He wanted to make an experiment testing how the motion of a cloud would correspond to the hail it produced, if the cloud's velocity and any changes to it corresponded with the falling hail's velocity. In lieu of control of the weather, da Vinci substituted a pitcher for the cloud and sand or water for the hail. Reliable clocks weren't available until about 140 years after da Vinci's death in 1519, the researchers note, so the inventor was forced to substitute the constant of time with space: by assuming that the time it took each water/sand particle to fall from the pitcher was constant, he just kept the pitcher at the same height throughout the tests. Da Vinci's sketch shows the positions of the falling material over the course of its trajectory toward the ground. By drawing a line through the position of the material at each instance in time, da Vinci realized that a triangle could be formed, with the drawn line being the hypotenuse. By changing the acceleration of the pitcher over the course of the experiment, one would change the shape of the triangle. Leonardo knew that the falling material would accelerate and that the acceleration is downward. What he wasn't wholly certain on -- hence the experiment -- was the relationship between the falling material's acceleration and the pitcher's acceleration.
In one particular case, when the pitcher's motion was accelerated to the same rate as the falling material being affected by gravity, an equilateral triangle was formed. Literally, as Da Vinci noted, an "Equatione di Moti" or an "equalization of motions." The researchers modeled da Vinci's experiment and found that the polymath was wrong in his understanding of the relationship between the falling object and time. "What we saw is that Leonardo wrestled with this, but he modeled it as the falling object's distance was proportional to 2 to the t power [with t representing time] instead proportional to t squared," said Chris Roh, a researcher at Cornell University and a co-author of the researcher, in a Caltech release. "It's wrong, but we later found out that he used this sort of wrong equation in the correct way." The team interpreted tick marks on da Vinci's sketches as data points the polymath made based on his eyeballing of the experiment in action. In lieu of a timepiece, da Vinci found the gravitational constant to nearly 98% accuracy.
Da Vinci understood some fundamentals of objects in motion. He wanted to make an experiment testing how the motion of a cloud would correspond to the hail it produced, if the cloud's velocity and any changes to it corresponded with the falling hail's velocity. In lieu of control of the weather, da Vinci substituted a pitcher for the cloud and sand or water for the hail. Reliable clocks weren't available until about 140 years after da Vinci's death in 1519, the researchers note, so the inventor was forced to substitute the constant of time with space: by assuming that the time it took each water/sand particle to fall from the pitcher was constant, he just kept the pitcher at the same height throughout the tests. Da Vinci's sketch shows the positions of the falling material over the course of its trajectory toward the ground. By drawing a line through the position of the material at each instance in time, da Vinci realized that a triangle could be formed, with the drawn line being the hypotenuse. By changing the acceleration of the pitcher over the course of the experiment, one would change the shape of the triangle. Leonardo knew that the falling material would accelerate and that the acceleration is downward. What he wasn't wholly certain on -- hence the experiment -- was the relationship between the falling material's acceleration and the pitcher's acceleration.
In one particular case, when the pitcher's motion was accelerated to the same rate as the falling material being affected by gravity, an equilateral triangle was formed. Literally, as Da Vinci noted, an "Equatione di Moti" or an "equalization of motions." The researchers modeled da Vinci's experiment and found that the polymath was wrong in his understanding of the relationship between the falling object and time. "What we saw is that Leonardo wrestled with this, but he modeled it as the falling object's distance was proportional to 2 to the t power [with t representing time] instead proportional to t squared," said Chris Roh, a researcher at Cornell University and a co-author of the researcher, in a Caltech release. "It's wrong, but we later found out that he used this sort of wrong equation in the correct way." The team interpreted tick marks on da Vinci's sketches as data points the polymath made based on his eyeballing of the experiment in action. In lieu of a timepiece, da Vinci found the gravitational constant to nearly 98% accuracy.
Polymath? (Score:5, Informative)
The correct stock phrase for Leonardo to be used by lame journalists is not "polymath", which occurs in the quote three times.
It's "Renaissance man."
Re: Polymath? (Score:1)
It's not just a matter of ignorance; their brains didn't develop the way ours did.
Re:Polymath? (Score:5, Funny)
In his own time :Leonardo would have been called a "polymath", not a "Renaissance Man". If anyone doesn't understand why, I have a genuine ancient Roman coin for sale with the date stamped right on it: "43 BC".
43 B.C.E. (Score:2)
We know it is a fake. The Christians in Rome at that time were few in number.
A real coin would have been stamped B.C.E..
Re: (Score:2)
I have a genuine ancient Roman coin for sale with the date stamped right on it: "43 BC".
Obviously fake! It would have been stamped AC (Ante Christum) because they spoke Latin (yes I know that would ruin the joke but pedant's gotta pedant).
98% accuracy (Score:1)
means off by a factor of 2.
Cool! (Score:2)
500-Year-Old Leonardo Da Vinci Sketches Show Him Grappling With Gravity
Sounds like the first graphic novel, and an awesome one at that!
Re: (Score:2)
500-Year-Old Leonardo Da Vinci Sketches Show Him Grappling With Gravity
Sounds like the first graphic novel, and an awesome one at that!
It's certainly graphic, but not in the way you think: Bernarduccio Gravity was his, um, manservant.
Re: (Score:2)
The tragedy... (Score:5, Interesting)
... is that there was no scientific publishing industry in the era. A brilliant person's research may propagate to their pupils or those who they sent letters to, but never spread en masse. Da Vinci worked in an amazing diversity of topics far ahead of his time, but his work remained relatively obscure until the modern era.
One of my favourites is how close he got to the theory of evolution. He was unusual for his era for mountain climbing, and during his climbs, he was fascinated by the geology in the rocks, and the fossils therein - and particular, noted that they were aquatic fossils [bioone.org], and ones that didn't exactly match any known living organisms. He rejected existing theories, such as that it was just forces in the earth that created fossils to mimic life, noting for example holes made by woodworms, noting how absurd it would be for forces in the earth to mimic the damage created by other organisms - and also for example how there were fossilized burrows between layers, and material moved from one layer to the next, and that the fossilized animals had growth rings and other indicators of having lived a whole life.. He also rejected the notion of "Noah's flood", as he observed that the fossils were sorted into layers, not jumbled together, and that organisms changed incrementally from one layer to the next, with no signs of violent chaos, with delicate structures buried in place. He reasoned that the oldest areas were deepest, and that you could match up layers between different geographic areas by them. His theory was that the area that was now land used to be sea, that periodic river floods sent sediment into the sea which buried organisms in layers one at a time, the organizations present having time to change between layers, and then the mountains were uplifted and eroded. His conclusion, due to the number of layers, was that the world was immensely ancient.
At the same time, Leonardo was obsessed with comparative anatomy of living animals. He drew side by side, for example, the corresponding bone and muscle structure of a human limb and a dog's limb [pinimg.com], showing how they had the same basic components, all the way up to our coccyx / vestigial tail - just slightly differing in size and shape of each part.
Honestly, had Leonardo lived for another decade or two, I really think he would have put these two things together and reached a full theory of evolution.
Re: (Score:2)
Re:The tragedy... (Score:4, Funny)
Da Vinci's mechanical lion, the world's first programmable automata actually built (he had drawn diagrams of automata before but not actually built them) was built in 1515, only four years before his death.
When someone says "If only they had lived longer", they don't mean "If only they had gotten to the stage of being right on their deathbed, and then that had dragged out for another decade or two." Up until he had a pair of strokes (the second of which killed him), Leonardo was just as acute as he had ever been - and indeed, even after the first stroke paralyzed his right hand, he still continued work on anatomical sketches and sketches of cataclysms with his left hand.
Re: (Score:2)
Life expectancy at birth back then was below 50 years of age, but if you made it past childhood life expectancy was not too dissimilar to todays (maybe mid to late 60s versus todays late 70s/early 80s). Morbidity was a lot higher though so a lot of people lived with rashes, chronic conditions, and tooth decay (look at the physicians report of the early US presidents for example).
"Da Vinci" (Score:4, Informative)
Is not his surname.
And neither is DeSantis (Score:2)
And the surname of the former leader of Iraq isn't Hussein. That is a patronymic, And his last name isn't Al-Tikriti, either, the meaning of which is "from the city of Tikrit."
But patronymics and place names have become surnames in modern usage, especially when the INS requires one.
Too much credit (Score:2, Insightful)
Re: Too much credit (Score:3, Insightful)
The time and place were hardly favorable.
If he'd lived centuries earlier in the Islamic world - where science and learning were in vogue, his accomplishments would be less impressive.
Europeans were animals until the Age of Enlightenment.
Re: (Score:2)
Europeans were animals until the Age of Enlightenment.
Which is why modern people mock early Greek philosophy, Roman engineering, Norse sailors, and British cooking.
Re: Too much credit (Score:1)
However, implying that the Norse were somehow enlightened is simply ignorant; the tree at Uppsala says otherwise.
Re: Too much credit (Score:3)
Common knowledge but not the sort that is actually true.
https://www.discovermagazine.c... [discovermagazine.com]
Re: (Score:2)
"Vogue" is the key word there. They wore it like a set of clothes, the way East Asia has been doing in this century (no offense, guys). The European Enlightenment took the harder and more dangerous path.
Prometheus seems more like a self-aware prophecy than an ancestral myth.
Re:Too much credit (Score:5, Insightful)
Re: (Score:3)
Larson would have helped the old boy ... (Score:3)
All squaaaaaared away! [wordpress.com]
Re: Larson would have helped the old boy ... (Score:2)
Sweet mercy that's on point. Well played, wish I had mod points.
not constant. (Score:1)
the "gravitational constant" is no such thing. anyone who seriously looks into it realizes this.
In lieu of (Score:4, Informative)
Re: (Score:1)
In lieu of literally means "instead of." Go read your last sentence again, it doesn't make any goddamn sense.
Maybe he found the gravitational constant instead of the timepiece.
(to nearly 98% accuracy)
Marble fossils (Score:3)
dubious (Score:2)
The purpose of the journal is to praise Leonardo.
Disappointed, I honestly wanted to see (Score:2)