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A Model of the Cosmos in the Ancient Greek Antikythera Mechanism

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121–130 of 136 posts

Re: A Model of the Cosmos in the Ancient Greek Antikythera Mechanism

#121

Earlier quoted context omitted.

We really like trash made of plastic.

I'm not so sure. A lot of trash plastic degrades over long periods of time. They might find the plumbing (which is a type of plastic that lasts longer), but that isn't trash in general.

How long will PVC pipes last? 1000 years is a long time.

Re: A Model of the Cosmos in the Ancient Greek Antikythera Mechanism

#122
post #84

Earlier quoted context omitted.

That's basically correct. Rome organized things on a very large scale with high productivity. Its replacement by less-organized tiny local systems cratered productivity, and the resulting systems couldn't afford to do the things Rome had done.

I came by this analogy by Dan Carlin. He was talking about "Germania" but the same applies to Sweden. When Sweden was christianized around 1000 AD this was basically equivalent to "being connected to the internet". Suddenly the vast resources (intellectual and communicational) of the catholic church where available to the (now christian) elite, giving them a huge advantage.

Expanding on the theme a little bit, here's the opening from East Asia Before the West ( https://www.amazon.com/dp/0231153198/ ):

> In 1592, the Japanese general Hideyoshi invaded Korea, transporting over 160,000 troops on approximately seven hundred ships. He eventually mobilized half a million troops, intending to continue on to conquer China. Over sixty thousand Korean soldiers, eventually supported by over one hundred thousand Ming Chinese forces, defended the Korean peninsula. After six years of war, the Japanese retreated, and Hideyoshi died, having failed spectacularly in his quest.

> The Imjin War "easily dwarfed those of their European contemporaries" and involved men and material five to ten times the scale of the Spanish Armada of 1588, which has been described as "the greatest military force ever assembled" in Renaissance Europe. [2]

> [2] The Spanish armada consisted of thirty thousand troops on 130 ships and was defeated by twenty thousand English troops.

The Korean peninsula is about 86,000 square miles. Japan is about 146,000. (Modern) Spain is 195,000 square miles.

The fragmentation of Europe had really severe effects on the resources it was able to muster.

Re: A Model of the Cosmos in the Ancient Greek Antikythera Mechanism

#123
post #62

Earlier quoted context omitted.

And that is super cool. I think we'd very significantly underestimate what our earlier brothers and sisters could actually do. And I also believe, since communication was spotty, and took a long time, that there were pockets of real Mastery in the world. But everyone didn't benefit, just because of the communication and knowledge-sharing difficulties from that time. I think Travelers had an amazing experience. They c…

You can do this today: hang out with a reindeer herder in Siberia and then pop over to Shanghai. Nothing's changed.

I agree, but the experience is a little bit less fantastic just because we know more. We know that the Futures in some places and we can still see the past. That was not true for Traveller way back then

Re: A Model of the Cosmos in the Ancient Greek Antikythera Mechanism

#124

Earlier quoted context omitted.

You can do this today: hang out with a reindeer herder in Siberia and then pop over to Shanghai. Nothing's changed.

I agree. I also have had a strange feeling my last few travels though. There is a pervasive sameness. Even in more traditional parts of India, Mexico. Obviously in places like the US, Western Europe, Canada. Once I step out of the temple, or get off the horse in the remote village, there’s this familiarity. I think an example is what I now think of as “the uniform”: sneakers, jeans, a t shirt with a brand on it. 9 to…

Yes I see this too. For The Travelers back in those times the world could look very different. And not that it doesn't look different now, but you're right there's a lot more of the same things were more homogenized and we know more about other places in the world than they ever could have back then

Re: A Model of the Cosmos in the Ancient Greek Antikythera Mechanism

#125

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 wea…

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.

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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.

Re: A Model of the Cosmos in the Ancient Greek Antikythera Mechanism

#126

Earlier quoted context omitted.

Can you elaborate on the Saturn V a bit more?

This came up when people started looking sideways at the ballooning costs of the Space Launch System. Even though we have extensive blueprints and even parts left over from Saturn V rockets, the institutional knowledge to use any of those things simply doesn't exist anymore, and would have to be re-created at exceptional cost of you wanted to build another one. https://space.stackexchange.com/questions/6281/why-not-b…

IIRC, even if we could, we can do better. For example a Saturn V engine is around 5,000 parts, though we've lost the knowledge to assemble them. However, a contemporary study of that found that, with modern manufacturing techniques, you can build an equivalent today with just 40 parts.

Re: A Model of the Cosmos in the Ancient Greek Antikythera Mechanism

#127

The design, so slim, so dense, so well engineered. There has to have been ones that came before. Too clever to not be an iteration. I wonder if we'll ever discover another.

> The design, so slim, so dense, so well engineered. It's the Apple M1 of its time.

There are some interesting parallels between the technological and cultural history of mechanical watches and smartphones... call it an iphone of its time, or apple watch of its time, and you're on to somthing.

Re: A Model of the Cosmos in the Ancient Greek Antikythera Mechanism

#128

Clickspring has been recreating the Antikythera[1] and findings[2] went into a research paper.[3] [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/

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.

Thanks for posting it

Re: A Model of the Cosmos in the Ancient Greek Antikythera Mechanism

#129
post #62
post #29

Earlier quoted context omitted.

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.

And that is super cool. I think we'd very significantly underestimate what our earlier brothers and sisters could actually do. And I also believe, since communication was spotty, and took a long time, that there were pockets of real Mastery in the world. But everyone didn't benefit, just because of the communication and knowledge-sharing difficulties from that time. I think Travelers had an amazing experience. They c…

> I think we'd very significantly underestimate what our earlier brothers and sisters could actually do.

I think what happens is that we forget that you can make a heck of a lot of even complicated and precise things with simple technology if you have a lot of time, have a lot of money to pay for labor, and don't need to produce more than a handful of the thing.

Need 100000 pairs of matched gears with a very precise fit, and you need them next month and cheaply? You need modern techniques.

Need one pair, and you've got years to produce it, and plenty of money? All you need is someone with a fine file to hand file the teeth, frequently checking the fit and tweaking it.

Re: A Model of the Cosmos in the Ancient Greek Antikythera Mechanism

#130

Earlier quoted context omitted.

The flipside of being so small and dense is that was fragile, which is a problem when you're trying to preserve something for a millennia. It was also undoubtedly expensive, meaning few were produced in the first place and they would be a prime target for thieves and artifact hunters. The one in the article could easily be the last one remaining.

Would the maker have really been thinking that the thing being made would still be usefull 50, 100 or 1000 years later? Sure, it could be used to look that far ahead, but would they have been concerned about longevity of the device itself?

On one hand, it's hard to imagine a craftsperson considering the life of a piece beyond the life of the craftsperson themselves.

But I suspect a craftsperson is first and foremost focused on the quality of materials, quality of the construction — no doubt in large part so that the piece is durable. The degree to which that adds to the longevity is probably unimportant.

Like arguing wether the workbench you built will last 200 years or 400. What does it matter and who could know?

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