I may be missing something here, but there's a conceptual leap from "the acceleration produced by gravitational force" to "gravity as a form of acceleration".
Da Vinci certainly appears to be exploring the former. The latter was Einstein's great insight. I don't see much in the article to persuade me that da Vinci was equating gravity and acceleration in the way Einstein did, and so the title seems a little too suggestive.
Indeed; this seems to be an extreme example of what might be called the "whig history of science", which interprets the past in the light of what we know today, attributing, to historical figures, modern concepts which they surely never even conceived of, and which would undoubtedly baffle them until they had been brought up-to-date with current knowledge.
> attributing, to historical figures, modern concepts which they surely never even conceived of, and which would undoubtedly baffle them until they had been brought up-to-date with current knowledge.
I don't think that's quite what Whig history is. The Wikipedia article doesn't seem to imply that, either. If there was a "Tory history", I think this case would be more like that, as it presents a past figure as being more enlightened (while Whig history typically does the opposite in order to extol progress).
Yeah, I'm not certain about the analogy, and I'm basing it more on how I have seen the phrase used in other places, but my cursory search did not dig them up. IIRC, the complaint is that, in order to present history as the steady progress towards what they regarded as an enlightened present, Whig historians attributed influential and powerful historical figures with liberal motives and goals. Tory historians might have attributed them with illiberal motives and goals that were sometimes thwarted (leading to what they regarded as a suboptimal present), which might well be more plausible in general.
Looking a little further into the article, I see it mentions a whig history of science that ignores failed theories and dead ends, and I would agree that this is not the same as attributing successful theories to people who probably did not hold them, though the latter does also tend to present science in 'march of progress' terms.
You're right but upon reading the article it does seem to actually be a form of Whig history - the article attributes the actual first work on this to Galileo (not Einstein), so while the headline is misleading, the article content seems to simply be surprised someone in the 14th century could be aware that gravity causes objects to accelerate at all.
The idea that the Galileo in being the first to formalise an equation for precise calculation of acceleration was by extension the first in history to conceptualise that acceleration occurs at all is a severe infantalisation of all scientists who preceded him.
A conservative history would emphasize more the contingency of the scientific process and the fact that it wasn’t inevitable that we’d get where we got.
Extending this: the Whig story on contemporary science (sp. as it affects policy) is that this is the best science because scientists have been improving it forever, while the conservative story is that maybe the scientists are wrong now, they’ve so often been wrong in the past.
"... a characteristic of that kind of historical writing in which the author seeks antecedents of present-day institutions or ideas in earlier historical periods. This kind of anachronism is considered to be a form of Whig history ..."
Except in the rare case where a new idea emerges and is introduced fully formed in its final stage, there are precursors of present-day institutions and ideas in earlier historical periods so seeking them would just be normal history.
That's true in general, but that is not what seems to be the case here, and the full article on precursorism linked by poiuyt098 suggests that correct usage would be confined to such cases.
Like the other reply I question whether this is an example of what's in your wiki article. However I have often wondered why something like Democritus' atomic model of the universe is given such praise when it probably had very little going for it at the time, and now I know the terminology for this phenomenon, so I am grateful for that :)
I call BS on this particular account of a Vinci ;;
He was millennia ahead of his time, and I personally believe he had an understanding of physics but was existing in a time where the tools available to his understanding were what was lacking.
This guy predicted eddy-based hydrodynamic in the cardio vascular system before "human biology" was considered a science.
Look at da vinci's designs for the eddy-hydro-pump system...
Maybe he was a time traveling engineer who needed to plant seeds of knowledge in our past on this timeline to ensure advancement and growth of Humanity.
Someone has already incorporated this into the wiki entry for historical development of gravitational theory, which may or may not be entirely justified:
That's an interesting article, including some challenges to Aristotle's views and gravity-related concepts introduced by Indian and Islamic scholars of the 6th - 12th century eras or so.
Isn't that a core problem with Wikipedia? I don't understand why its reputation on HN improved, a few years ago, from 'infotainment but a symbol of mis-/disinformation' to 'source of truth'.
Which was in itself the genius of this newton guy. It’s one thing to realise that objects falling accelerate. It’s another to realise that F=ma, and that this can model objects falling as well as a bunch of other things. Surely da Vinci wasn’t lucky enough to have an apple fall on his head ? :)
> "gravity as a form of acceleration". […] The latter was Einstein's great insight. […] equating gravity and acceleration in the way Einstein did
This sounds like a gross misinterpretation of what Einstein said.
Einstein's great insight was that gravity defines inertial (i.e. non-accelerated) frames of reference. Put differently, in free fall you are not in an accelerated frame, despite what an outside observer on the surface of Earth might say. This is commonly abbreviated by "All massive bodies follow the same (inertial) trajectories in the presence of gravity, irrespective of their constitution", which is the Equivalence Principle.
What you are maybe referring to is what an observer experiences who stands still on the surface of a massive body: They can't free-fall, and so they're not in an inertial frame (= the thing defined by gravity) and thus actually accelerate upwards from the point of view of spacetime.
I see. Personally, the way I have always interpreted that quote is that here, in this particular case, "gravitational field" is supposed to mean "someone standing on the surface of Earth, experiencing gravity" or, more generally, "an observer in a spacetime who's not in free fall / not moving along a geodesic" (but e.g. standing on the surface of a massive body).
Otherwise, as outlined in my previous comment, it does not make any sense.
>I don't see much in the article to persuade me that da Vinci was equating gravity and acceleration in the way Einstein did
Thinking of the effect on speed of things falling down as acceleration (as opposed to constant), and even coming up with a formula, is already a bridge between these two things.
No, it is not at all a bridge to Einstein’s ‘gravity and acceleration are equal’, which is "the gravitational force is physically indistinguishable from any acceleration", which has to do with changing to relatively accelerating reference frames.
The insight of da Vinci’s here is anticipating Newton, not Einstein. And yes, this is already an accomplishment, but not the outlandish one the article would imply.
Hence "a bridge". It's not Einstein's result, but it's moving towards Netwon (and eventually that) from older ideas about the behavior of things "falling" (such as proportional to their weight and constant speed).
Early on in my physics career, my supervisor asked me to keep in mind “it’s about speed, not velocity” when doing calculations. In general a force is a change in momentum, i.e. a change in speed. Acceleration is a change in speed relative to some frame. It’s quite possible that da Vinci may unknowingly have seen gravity as an acceleration (as in my example above) and taken the next step to seeing it as a change in speed.
But the water droplets/sand particles do NOT form a straight line if you accelerate the jug. You have to decelerate the jug with exactly the right timing to form a straight line, not accelerate it. Nor do the beads in the Caltech video form a straight line, despite their dishonest attempt to arbitrarily impose a straight line on beads that are clearly not in a straight line.
In the second diagram, which is alleged to be an attempt to plot acceleration due to gravity to the position of an accelerating water jug, the values [0,1,2,4,8] are marked on the x-axis, and [0,-1,-2,-4,-8] on the y-axis. Da Vinci then plots lines from [0,-8] to the points (0,0),(1,0),(2,0),(4,0),(8,0). Doing so doesn't really establish any sort of relationship between accelerating jugs and acceleration due to gravity, even allowing for an incorrect equation of motion for an accelerating object.
Da Vinci spent most of his early career trying to sell military technology to potential patrons (largely if not completely unsuccessfully). One of the pieces of technologies he was trying to sell was a process for calculating improved artillery range tables (tables of elevation vs. range). He didn't manage to sell that either.
The second diagram is more easily interpreted as a doodle that makes an unsuccessful attempt to scry a relationship between elevation and range for artillery pieces.
Indeed, this can be thought of intuitively (though it is slightly counter-intuitive): as the article says, if the jug is moving at a constant speed, the drops will actually make a vertical line under the jug. This is because each drop will be move with the same horizontal speed as the jug.
A decelerating jug, as proposed above, would actually create a backwards line or curve. The drops at the bottom works actually be ahead of the jug.
An accelerating jug is the only way you can get the bottom drops behind the jug.
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My previous comment:
Indeed.
I was pretty sure this was correct, but wanted to model it to confirm. On a Chromebook right now, so Scratch was the easiest way to model and share:
In your program, each of the balls starts with zero horizontal velocity. This is not analogous to real life, in which the droplets from the jug will have the same horizontal velocity as the jug at the moment they detached. They shouldn't fall straight down, they should follow a ballistic arc. I don't have the skills to set up a simulation of this right now, but I wouldn't be too surprised if the total of those ballistic arcs forms a straight line.
You're totally right. Adding in the ball's horizontal speed makes the article's statement correct: you do have to accelerate the jug by g in order to get a straight line.
That's what I thought as well... But I think what the diagram isn't showing is that the drops are actually moving horizontally to the left at the speed that the jug was moving at the time the drop left the jug. This means each one is moving to the left slightly faster than the one before it... And as they fall this creates an increasing horizontal distance between them... The line is kept at a constant angle due to the fact that the earlier drops are falling downward slightly faster than the later drops. The horizontal and vertical difference between the adjacent drops maintains a 1 to 1 ratio.
>But the water droplets/sand particles do NOT form a straight line if you accelerate the jug. You have to decelerate the jug with exactly the right timing to form a straight line, not accelerate it.
You can make a right triangle via either acceleration or deceleration at the same rate as gravity. However, you can only make an Isosceles Right Triangle with acceleration
Actually a constant horizontal velocity will make a straight vertical line of droplets under the jug. This is because the drops will have the same horizontal velocity as the jug.
That's true. In the zero acceleration case you get a vertical straight line. If you have acceleration or deceleration equal to G, you get a straight angled line. If you have any acceleration or deceleration that doesn't match G, you get a curve
> "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," Roh says. "It's wrong, but we later found out that he used this sort of wrong equation in the correct way." In his notes, da Vinci illustrated an object falling for up to four intervals of time—a period through which graphs of both types of equations line up closely.
All lines look straight if plotted on a log-scale and drawn with a thick enough marker.
Just finished reading Leonardo da Vinci by Walter Isaacson. Was a very good read, learned a lot about da Vinci that I was never taught or discovered on my own.
^ I also just finished it. Really loved it. Really loved how Isaacson allowed himself to interject here and there with his own thoughts and his own appreciation of daVinci. I felt like it really highlighted some of the unique aspects of the man.
I also came to appreciate some of the artwork and now I can look at the Mona Lisa and have my own thoughts on the work.
I would think that individuals from antiquity would understand that an object rolling down hill picks up speed, or a rock dropped from higher hits harder.
The existence of acceleration aspect may not have been novel, but measuring the rate seems to be the novel part
isn't indeed easier to measure a rolling object going down from a ramp? measuring water falling from a jar while moving the jar sounds very complicated.
IMHO, this is less surprising discovery about him considering this probing is around 300 years ahead of his time, and Da Vinci already has proof for concepts 500 ahead of his time.
Speaking of Leonardo: I noticed that the Mona Lisa has a new much better (more transparent) protection glass, at least new since I last visited a few years ago. It makes it imho more worthwhile to go see it. Also pro tip, go in February -- there's only a moderate crowd, not a crazy dense throng as in the summer.
Here's another pro-tip: there are other "copies" of the Mona Lisa which, IMHO, are more interesting to look at than the deeply varnished one on display at the Louvre. The Prado Mona Lisa is one I particularly like.
Mathematicians and physicists in several parts of the world – including Europe – had a pretty solid scientific understanding of gravity and acceleration well before the 1500s, so I'm not sure why this is so notable.
Da Vinci's work on water's management and hydrolics ultimately pushed us through the technological wall the Romans hit, that lead toward waterworks and the first industrial revolution.
Would it be correct to say that you feel gravity/weight because the ground is accelerating upwards in your local reference frame, and your body's inertia resists that acceleration?
Years ago when I was really into [various philosophies] and [secret society]...
They stated that gravity actually pushes up but it is mass and movement that counteract gravity's push
it was the vibrations of cymatics and sound that could counter-act mass on gravity and take advantage of gravity pushing up... and this is how the ancients knew to move/manipulate matter in space...
This is what Tesla alludes to through 3/6/9 vibrations, and how Ed Skalnanin built the coral castle.
Its all about changing harmonious vibrations, and both Skalnanin and the Egyptions had interesting vibratory circular tools which are missing parts, but basincally from spinning them they could manipulate the vibratory frequency of matter such that their mass didnt effect gravity and took advantage of gravity's push...
So the idea was to think of mass as the inverse of gravity when the frequencies are not sync'd..
I know it science-fiction, but its fun to think about.
I think the more interesting effect to look at is centrifugal forces. I think that everything spins because a constant turning (warping) of space-time (gravity pushing) 'UP' is how mass stays 'co-herent' 'co-hesion'
Think of superconductive levitation. Slow the spin of an object "in-motion" and it can levitate...
What if rather than through temperature control on manipulating the rotation of Atoms, you could use sound to levitate objects.. (seen the frog levitating in ultra-sound...
The conspiracy idea is that it is mapped out in certain stone carvings for the frequency.
Like the Rose church, which has Cymatic [atterns carved into its walls, which tell you the frequencies used...
Think of how certain alloys are made under magnetic
fields, and ceramics. Imaging forging an alloy under both a magnetic field & a cymatic frequency.
I love this conspiracy theory as its a great foundation to science-fiction writing as well.
I don't see how any of that follows. If the ground is accelerating upwards, then making an object levitate would require stopping that acceleration. Even with scifi magic, that problem sounds more difficult than "blocking gravity" in one location.
When you aren't moving you feel pressure due to you and the planet trying to free fall into each other to make a black hole, or at least pass each other in very close orbit, but being blocked by the repulsion of your electrons vs your shoes'/floor's/ground's.
When you are falling, you are feeling the air that is hitting you because it is not falling, causing the electron effect above, and your guts feel weird because your brain is noticing that nothing is pushing on them anymore.
One of the things that irritates me a little about Da Vinci is he gets disproportionate credit for inventing things that don't actually work. The list of things he invented that he actually got to work is vanishingly small.
Even when claims are made that he is "prescient", there has never been, nor will there ever be a functional "helicopter" that looks like Da Vinci's helicopter.
You always compare people against their contemporaries. Da Vinci has his reputation because he was exploring ideas far above and beyond his contemporaries, and because his breadth of knowledge and skills covered a wide swathe of subjects.
His killing machines seemed to work just fine [1], although some seem to go towards a more interesting counterpoint for when HBO will make the inevitable series Da Vinci: The Machine, staring Leonardo di Caprio [2].
I actually think the tools and environment are more important that the genius.
There are thousands, maybe millions of people with genius-level intellect, all capable of being the next Leonardo or Einstein. Out of them only a small fraction grew up in the right environment, usually wealthy families, but that's still a lot of people. The next, and I think most important requirement are the tool needed to make the discovery, or even just to know that a discovery is to be made.
For example, if you don't have the tools needed to notice that the speed of light isn't infinite, special relativity makes no sense. General relativity requires even more tricky measurement, in fact it didn't came long after people noticed something was wrong with Newtonian mechanics.
Tools are in the general sense. Physical object like a computer or a good telescope, manufacturing techniques and even maths, think of the "shoulders of giants" thing.
So it would be more like giving the graphing calculator the genius it needs rather than going back in time and giving the genius a graphing calculator.
Yes! During his lifetime, he was mainly seen as an artist. He probably earned well but still magnitudes lower than what he would have needed to get something done. Just imagine if there would have been something like venture capitalists.
I guess in terms of the big five, he was super-high in openness but no so high in conscientiousness. In today's world he would fit better because he could run an institute or a company.
I asked an Italian native speaker about this and she said she calls him “da Vinci.” She has a PhD in linguistics, and in general she’s pretty precise with her language. She doesn’t seem to see anything wrong with it. Just as a datapoint.
You’re wrong because everyone in the English speaking world refers to him as da Vinci which means da Vinci is the name that refers to the person Leonardo. That’s how names and language work. Now back to playing with my LEGOs.
Da Vinci certainly appears to be exploring the former. The latter was Einstein's great insight. I don't see much in the article to persuade me that da Vinci was equating gravity and acceleration in the way Einstein did, and so the title seems a little too suggestive.