For added incentive for those who make the poor call to not check out the videos, he doesn't just recreate the mechanism... He invents or re-invents the tools and techniques required to make it, using only materials and technology known to be available at the time.
Great videos. It's so fascinating that they were able to make such a device back in that time. Still wondering how they have done without the machines we have these days, though.
What happened to these advanced civilization of the antiquity? We have drawings of highly advanced siege engines yet it seem that after the fall of Rome we all went back to fighting with sticks for a few centuries. Why is that?
In the case of the Antikythera mechanism, it turns out the knowledge and technology weren't entirely lost. There's a fairly well-established throughline now from Babylonian observation-based astronomical tables to Greek philosophical views and mathematics (and craftmanship) to Arabic astrolabes (retaining some of the gear-train tech) and then back to Europe, to the monastic astronomical clocks. Then the escapement was invented and added in, and boom you got modern industrial technology.
There are a lot of loss and bottlenecks along that journey, though. And many notable locations, installations and individuals. The history of instrument-making and how it is intertwined with philosophical and religious views on the skies and the topology of the universe is quite fascinating (e.g. the motivations for observing the sky, being able to produce predictions at all, crafting models, etc).
Knowledge is passed on from master to apprentice. Nearly-universal literacy helped to alleviate this issue somewhat, but even today most practical knowledge is passed on by people working together.
The result is that even a gap of a single generation is enough for some knowledge to be lost. That's why Roman concrete was forgotten, why we can't build a Saturn V anymore, why you can't just start a chip-fab with enough money, and why it's so hard to maintain code without access to someone that designed the code-base.
Most things, even if they're written down, are more accurately modelled in someone's brain.
Very broadly speaking we tend to now think of history or time as being fairly linear with progress being made while ancients tended to think of history as cyclical and those before them as random.
The Antikythera mechanism or the somewhat inexplicable late bronze age collapse and the unidentifiable "sea people" that caused it are good examples to indicate there's some degree of cyclicality, wherein people stumble across ruins more advanced than their own civilization and wonder where they could have gone.[1]
Getting to the "why" part, Peter Turchin's work expanding on Ibn Khaldun's concept of Asabiyyah seems the most compelling to me.
The fall of the Roman empire was essentially a post-apocalyptic event for the West. The economic and political collapse of Rome's satellite states halted the progress of technological and cultural development across subsequent generations. Many ancient Greek classics, such as the works of Aristotle might have been lost forever had they not been saved by Islamic scholars.
And don't think it couldn't happen again. We've stored the entirety of our cultural knowledge on an ephemeral digital network that depends upon an intricate and vastly complex technological infrastructure. If that collapses, so does modern civilization, and we're back to horses and buggies.
When the Western Roman Empire collapsed, the various successor states didn't have enough organizational capacity / surplus / numbers to do things like arm permanent standing armies with advanced siege engines, or build aqueducts and long paved roads everywhere. But there was still technological advancement in plows, water mills, and crop rotation even shortly after the collapse.
A imperial decline mostly means a lot of chaos for a couple of decades, I think the most recent example would be the soviet union. It took Putin like almost 2 decades to recover/stabilize from the western plunder of Russia in the 90s via Russian oligarchs. Russia lost a lot of brain power in that period and lost a lot of institutional knowledge which might takes generations to rebuild again.
Also the engineers and high ranking members of society have to resources to flee to more stable regions and carry their knowledge with them. Its also the engineers that are usually given grace or offers by a opposing forces/rivals.
Can anyone help me understand why gears with prime numbers of teeth would not be mechanizable?
For Venus the original designer faced a dilemma: the known period relation (5, 8) was very inaccurate, whereas the accurate (720, 1151) was not mechanizable because 1151 is a prime number, requiring a gear with 1151 teeth.
I thought that gears with prime numbers of teeth would be advantageous because it would spread the wear evenly across the gear that it contacted.
In addition to the other comments, gears with a prime number of teeth were undesirable because they couldn't be laid out by iterative division of a circle. A gear with 64 teeth can be easily laid out by dividing the circle into fourths, dividing those fourths into fourths, and again to get 64 even divisions. For a gear with a prime number of teeth, the only option is to guess-and-check walk a pair of calipers around the circle, adjusting them iteratively until you make the exact number of steps and wind up at the exact same place. Without vision magnification, this was extremely difficult to do accurately. Clickspring (see top comment) did some experiments with a large dividing plate that makes the process somewhat easier, but it would still be far more difficult than making a non-prime number of teeth.
The other commenters are all correct, but I wanted to say something I didn't see mentioned: you can totally do it, it's trivial to imagine a working gear with 13 teeth. But you can't make two smaller gears that have a ratio of 1:13, because 13 is prime, so you literally have to make it be 1 gear. That means the 1:1151 ratio literally has to be 1 big gear, which is hard to make.
You do have a misunderstanding about the wear. Unless your gear is oscillating back and forth, it will always move in a complete circle and always wear the teeth evenly. Note that the involute tooth design leads to less wear on an individual tooth, but it doesn't have to do with how many teeth are on the gear.
You can't split them up into several smaller gear pairs, so you actually need two gears with 720 and 1151 teeth. A gear with 1151 teeth is impractical to make, both in terms of size and in terms of the manufacturing capability at the time.
One way to do a ratio of 720:1151 is to construct a gear with 720 teeth, and a second gear with 1151 teeth, and mesh them together. This wouldn't be impossible, but it would be a lot of work. If it takes you 5 minutes per tooth, that would be 156 hours sitting there with a file, grinding teeth away. Plus, perhaps most importantly, they'd be enormous- you're talking gears that are like 2 feet across for 1/8" teeth. The Antikythera mechanism was a little over a foot on its long axis, and 8 inches across the other.
Let's say instead of a ratio of 720:1151, the ratio happened to be 720:1147. You construct gears with 24, 30, 31, and 37 teeth. (24x30 = 720, 31x37 = 1147) 720 and 1147 are still coprime, so you can't be reduced the way 720:1152 can be reduced to 5:8. (or more likely, 20:32) You connect the teeth of your 24 tooth gear to your 31 tooth gear, connect your 31 tooth gear to the 30 tooth gear via a common shaft, and connect the teeth of your 30 tooth gear to the 37 tooth gear. The final gear ratio of this mechanism will be 720:1147.
This only works because both 720 and 1147 can be factorized into manageable primes.
Constructing those 122 teeth will take 10 hours at 5 minutes a pop, which is a lot of work but not unmanageable. Furthermore, those four gears can be constructed by four workers, and it will take the 37 tooth worker 3 hours, but a worker working on a 1151 tooth gear will require 96 hours. The gears will be much smaller, easily fitting in your fingers.
----------------------------------------
It's also more difficult to construct gears with prime numbers of teeth. If you need to construct a gear with 32 teeth, you bisect the angles a few times until there are 32 portions, then cut teeth there. If you need to construct a gear with 30 teeth, you split it carefully into thirds, carefully split each third into fifths, and then cut two teeth in each fifth. This would probably be a bit rough, but probably within tolerances. You split into thirds or fifths with a straight edge and compass, the way you can with bisecting, but you can wrap some string around the edges and even split string into thirds pretty easily, and fifths with some effort.
If you need to construct a gear with 31 teeth, there's not really a convenient way to do it. There's a lot of pedagogy involved; I think the best way would be to guess about how large a tooth is gonna be, add that to a string you've wrapped around the blank wheel, then repeatedly bisect the string into 32nds, then check if the 32nd tooth overlaps the 1st tooth well enough. If not, start over. But there might be a more convenient way to do it.
It's tough to make gears with that many teeth, especially if you want them to mesh with smaller gears.
Also, meshing against a 1-tooth gear is problematic, so you would need to probably increase that to >4 teeth to have it work. Then your bigger gear needs to have >4x the teeth to get the desired ratio.
1151 is too many teeth for a gear. The teeth would not be deep enough to transmit power effectively. You can't make this exact ratio using gears with fewer teeth because 1151 is prime (more generally, whenever the numerator and denominator are coprime).
This cites Price's "Gears from the Greeks" (1974), one of the major papers on the Antikythera Mechanism. I read through it once for a university assignment. It's fascinating and well worth checking out if you're interested in the device.
Archimedes in the Sand Reckoner cites to be solving on a problem from the "Eastern Philosophers". The problem is also in the Vajra Sutra where the numbers of sands in the cosmos is contemplated.
Archimedes Father was an astronomer.
Great parallel lives material that never maid it into the original.
The Antikytheron is written in a Corinthian dialect, from where Archimdes father is said to have come from.
My musing consiracy theory for the Roman sacking of Syracuse was for the Antikythera from which harvest and thus taxes could be better calculated - i.e. Thales.
But the Romans killed the only guy who understood how the Antikythera worked.... so it became a generals paper weight.
If you want to go deeper, I can recommend Jo Marchant's book on the device as a lovely summary of what it does, the research history and how it all relates to the rest of world history.
Sadly or maybe only interestingly, the Clickspring folks' recent article[1] arguing that the mechanism used a lunar calendar doesn't seem to be cited in this new article.
Given how recent his publication is, it is quite likely that the authors of this were already in the final edit stages when they became aware of it, and so it didn't affect anything in their paper and so wasn't cited.
Sometimes I think the Antikythera Mechanism is more of an ancient Greek Rorschach blot: what people are certain it was supposed to do may reveal more about what is important to them than it does about the mechanism and its maker's intent.
I read someware that in 2000 years the books we managed to save from the middle ages and up to about 1850 will still be around but anything printed after that will be gone because the paper of the modern age is to fragile to last.
[+] [-] jdefelice|5 years ago|reply
[1] Playlist: https://www.youtube.com/watch?v=ML4tw_UzqZE&list=PLZioPDnFPN...
[2] https://www.youtube.com/watch?v=MkKgdq57uOo
[3] https://bhi.co.uk/antikytheramechanism/
[+] [-] rfrey|5 years ago|reply
[+] [-] wdb|5 years ago|reply
Thanks for posting it
[+] [-] dylan604|5 years ago|reply
[+] [-] JKCalhoun|5 years ago|reply
I wonder if we'll ever discover another.
[+] [-] belval|5 years ago|reply
[+] [-] sho_hn|5 years ago|reply
There are a lot of loss and bottlenecks along that journey, though. And many notable locations, installations and individuals. The history of instrument-making and how it is intertwined with philosophical and religious views on the skies and the topology of the universe is quite fascinating (e.g. the motivations for observing the sky, being able to produce predictions at all, crafting models, etc).
[+] [-] ontekhunhsentuh|5 years ago|reply
The result is that even a gap of a single generation is enough for some knowledge to be lost. That's why Roman concrete was forgotten, why we can't build a Saturn V anymore, why you can't just start a chip-fab with enough money, and why it's so hard to maintain code without access to someone that designed the code-base.
Most things, even if they're written down, are more accurately modelled in someone's brain.
[+] [-] kipchak|5 years ago|reply
The Antikythera mechanism or the somewhat inexplicable late bronze age collapse and the unidentifiable "sea people" that caused it are good examples to indicate there's some degree of cyclicality, wherein people stumble across ruins more advanced than their own civilization and wonder where they could have gone.[1]
Getting to the "why" part, Peter Turchin's work expanding on Ibn Khaldun's concept of Asabiyyah seems the most compelling to me.
[1]https://www.poetryfoundation.org/poems/46565/ozymandias
[+] [-] progre|5 years ago|reply
[+] [-] rozab|5 years ago|reply
https://youtu.be/pW-SOdj4Kkk
[+] [-] tokai|5 years ago|reply
[+] [-] krapp|5 years ago|reply
And don't think it couldn't happen again. We've stored the entirety of our cultural knowledge on an ephemeral digital network that depends upon an intricate and vastly complex technological infrastructure. If that collapses, so does modern civilization, and we're back to horses and buggies.
[+] [-] jtolmar|5 years ago|reply
[+] [-] dragonelite|5 years ago|reply
Also the engineers and high ranking members of society have to resources to flee to more stable regions and carry their knowledge with them. Its also the engineers that are usually given grace or offers by a opposing forces/rivals.
[+] [-] unknown|5 years ago|reply
[deleted]
[+] [-] 4gotunameagain|5 years ago|reply
[+] [-] LegitShady|5 years ago|reply
[+] [-] m-app|5 years ago|reply
[+] [-] nograpes|5 years ago|reply
For Venus the original designer faced a dilemma: the known period relation (5, 8) was very inaccurate, whereas the accurate (720, 1151) was not mechanizable because 1151 is a prime number, requiring a gear with 1151 teeth.
I thought that gears with prime numbers of teeth would be advantageous because it would spread the wear evenly across the gear that it contacted.
[+] [-] vgel|5 years ago|reply
[+] [-] CGamesPlay|5 years ago|reply
You do have a misunderstanding about the wear. Unless your gear is oscillating back and forth, it will always move in a complete circle and always wear the teeth evenly. Note that the involute tooth design leads to less wear on an individual tooth, but it doesn't have to do with how many teeth are on the gear.
[+] [-] biggieshellz|5 years ago|reply
[+] [-] nwallin|5 years ago|reply
Let's say instead of a ratio of 720:1151, the ratio happened to be 720:1147. You construct gears with 24, 30, 31, and 37 teeth. (24x30 = 720, 31x37 = 1147) 720 and 1147 are still coprime, so you can't be reduced the way 720:1152 can be reduced to 5:8. (or more likely, 20:32) You connect the teeth of your 24 tooth gear to your 31 tooth gear, connect your 31 tooth gear to the 30 tooth gear via a common shaft, and connect the teeth of your 30 tooth gear to the 37 tooth gear. The final gear ratio of this mechanism will be 720:1147.
This only works because both 720 and 1147 can be factorized into manageable primes.
Constructing those 122 teeth will take 10 hours at 5 minutes a pop, which is a lot of work but not unmanageable. Furthermore, those four gears can be constructed by four workers, and it will take the 37 tooth worker 3 hours, but a worker working on a 1151 tooth gear will require 96 hours. The gears will be much smaller, easily fitting in your fingers.
----------------------------------------
It's also more difficult to construct gears with prime numbers of teeth. If you need to construct a gear with 32 teeth, you bisect the angles a few times until there are 32 portions, then cut teeth there. If you need to construct a gear with 30 teeth, you split it carefully into thirds, carefully split each third into fifths, and then cut two teeth in each fifth. This would probably be a bit rough, but probably within tolerances. You split into thirds or fifths with a straight edge and compass, the way you can with bisecting, but you can wrap some string around the edges and even split string into thirds pretty easily, and fifths with some effort.
If you need to construct a gear with 31 teeth, there's not really a convenient way to do it. There's a lot of pedagogy involved; I think the best way would be to guess about how large a tooth is gonna be, add that to a string you've wrapped around the blank wheel, then repeatedly bisect the string into 32nds, then check if the 32nd tooth overlaps the 1st tooth well enough. If not, start over. But there might be a more convenient way to do it.
[+] [-] wolfd|5 years ago|reply
Also, meshing against a 1-tooth gear is problematic, so you would need to probably increase that to >4 teeth to have it work. Then your bigger gear needs to have >4x the teeth to get the desired ratio.
[+] [-] blt|5 years ago|reply
[+] [-] redwall_hp|5 years ago|reply
[+] [-] noisy_boy|5 years ago|reply
[+] [-] maxerickson|5 years ago|reply
So it would be a coincidence, likely without much meaning.
[+] [-] rexreed|5 years ago|reply
https://en.m.wikipedia.org/wiki/Antikythera
[+] [-] exDM69|5 years ago|reply
Thus the mechanism has no relation to the sanskrit word.
[+] [-] jcrubino|5 years ago|reply
Archimedes in the Sand Reckoner cites to be solving on a problem from the "Eastern Philosophers". The problem is also in the Vajra Sutra where the numbers of sands in the cosmos is contemplated.
Archimedes Father was an astronomer.
Great parallel lives material that never maid it into the original.
The Antikytheron is written in a Corinthian dialect, from where Archimdes father is said to have come from.
My musing consiracy theory for the Roman sacking of Syracuse was for the Antikythera from which harvest and thus taxes could be better calculated - i.e. Thales.
But the Romans killed the only guy who understood how the Antikythera worked.... so it became a generals paper weight.
[+] [-] sho_hn|5 years ago|reply
[+] [-] throwaway81523|5 years ago|reply
[1] https://bhi.co.uk/antikytheramechanism/
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