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Early navigation. Antikythera Mechanism.

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Early navigation. Antikythera Mechanism.

Old 16th Mar 2021, 17:17
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Hopefully Clickspring will get to complete his replica before too long, so we can all see how this amazing machine worked for real. I find the idea that there were skills like this around over 2,000 years ago just mind boggling. I can't help but compare this to the other recent thread about the Apollo Guidance Computer. It seems that a similar understanding of science and technology went into designing and building both.

The comment in the video lecture (relating to Arthur C Clarke, I think) about where mankind might be today, had the technology and knowledge in ancient Greece have gone in a different direction reminded me of being really puzzled when on holiday in Egypt about 30 years ago. There was evidence there of advanced science and engineering skills from several thousand years ago, coupled with evidence all around that many in modern Egypt would struggle to repair a bicycle. Made me wonder what had happened to both prevent that knowledge advancing, and , in fact, to actually seem to make it go backwards. Perhaps what we think of as technological civilisation is really a very fragile thing, that could be lost rather easily.
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Old 16th Mar 2021, 17:40
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Yes, that's for sure. The notion that the portal(s), with their closable doors, would be aimed at Sirius if we map the sky back 3000 years has fascinated me for years, but it wasn't solid science, only an enthusiastic presenter with a laptop. But just who would think along these lines?

One thing my link left me gasping for was more about another layer of library under the sacked one in Alexandria. More things on the list. I'll try to find the article about the age of that skull in north Africa. Of course, this is all too easy to be steered down the route to Atlantis. But why then would the Antikythera mechanism be geocentric? The brains needed to display that 9 year variation on a bogus heliocentric model would have surely known the truth. As I inferred, perhaps even they were not allowed to consider us being anything less than God's focal point.
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Old 17th Mar 2021, 03:20
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This is odd. Nick Deakin's post of the picture on a lump of granite - it's even got the pin holes!

A lot of arguments on Quora, many from years back.

https://www.quora.com/Is-the-Antikyt...nism-overhyped
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Old 17th Mar 2021, 06:51
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Somehow I seem to have watched the whole thing, and I am not asking for my time back. A well-spent couple of hours.

My first theory is that it was a teaching device for a Greek school, incorporating the sum of human knowledge of the heavens in a mathematical and artistic mechanical model, as opposed to or complementing theoretical written texts.

Was the sunken ship loaded with loot from the destruction of a city, or was it possibly carrying cultural objects out of a city under siege, from a civilization in immediate danger of cultural extinction?
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Old 17th Mar 2021, 08:29
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What I find incredible is the ability to make the components to such exacting tolerances, something the Chinese didn’t manage for clocks till the 10th century - and the failure of his gear maker being able to consistently do so leading to the failure of Babbage to finish his Difference and Analytical Engines.
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Old 17th Mar 2021, 08:52
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Also, in Egypt; the technology to fit stones together so perfectly that a piece of paper cannot be slid between them. And the stone jars and plates which were clearly made on a lathe. And the hieroglyph 'carvings' which were probably etched by a chemical process similar to printing. The perfection of the Sphinx carving and surface finish. The incredible flatness and trueness and perfect right angles of massive stone sarcophagi found deep inside the pyramids. The amazing trueness and flatness of stone pillars and structures of other buildings - something we would struggle to achieve today.

So, no doubt, there was very advanced technology around in those ancient times. The question is, where are the tools they used? There seems to be no evidence of them - except the Antikythera mechanism. What did the ancients do with the tools they used? All we have found so far are copper items - too soft to carve stone, especially to such fine tolerances and perfection. There must have been diamonds to carve stone.

And what happened to the civilisation itself? There is evidence of huge abandoned cities now being discovered in the desert with drone surveys etc. Why did they leave. Why did their descendants lose all their knowledge? There must have been an horrendous plague like Covid or perhaps global warming, or thousands of years of droughts. But even so, where are the tools?
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Old 17th Mar 2021, 16:47
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Uplinker,

I ask simply out of curiosity - is there any solid evidence that either the Egyptians, Greeks or Romans used lathes for metal work? I ask because of the concentric tubes used in the Antikythera Mechanism.
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Old 17th Mar 2021, 17:16
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Pedal turning lathe, Ancient Greek Technology

THE TEN BOOKS ON ARCHITECTURE


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Old 17th Mar 2021, 22:25
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What I find incredible is the ability to make the components to such exacting tolerances, something the Chinese didn’t manage for clocks till the 10th century - and the failure of his gear maker being able to consistently do so leading to the failure of Babbage to finish his Difference and Analytical Engines.
ORAC,

To be fair, Babbage required much higher precision and accuracy than the makers of the Antikythera mechanism, who used triangular teeth on the gears. There is a very good discussion of these teeth and why they were advantageous, at 3:10 in this Clickspring video:


Antikythera Mechanism gears:


Difference Engine gears:

Last edited by India Four Two; 17th Mar 2021 at 23:00.
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Old 17th Mar 2021, 23:54
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Remember the large hub not being turned out of the solid, but a rectangular belt heated and fastened to the periphery. I've no doubt the result would still need turning so I wonder why so much extra work.
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Old 18th Mar 2021, 09:10
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Originally Posted by Bergerie1 View Post
Uplinker,

I ask simply out of curiosity - is there any solid evidence that either the Egyptians, Greeks or Romans used lathes for metal work? I ask because of the concentric tubes used in the Antikythera Mechanism.
I don't know - I am only going by the high uniformity of the stone jars and plates in museums. It is hard to believe such things were made freehand, but where is the evidence for machine tools? The huge stone sarcophagi are, apparently, flat and square to modern standards: a couple of thou over a couple of meters, so did the Egyptians have huge stone finishing machine tools?

I guess it is possible that lathes and machine tools were made from wood, with stone cutting edges? The wood has rotted away, and the stone pieces fell into the sand?

Bodgers in the woods, used to form chair legs for furniture with wooden lathes powered by a foot treadle, (and metal chisels). So I guess you could make a similar lathe to turn pieces in brass, which is relatively soft.

The whole thing is fascinating, and it would be good to know how they really did it. Any machinists in the house who could comment?
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Old 18th Mar 2021, 09:48
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Perhaps this gentleman had the answers after all?
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Old 18th Mar 2021, 09:53
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Hidden in plain sight?

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Old 18th Mar 2021, 11:34
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Utterly fabulous lecture.
A great find Loose, thoroughly immersive and enthralling, and I just couldn't turn it off. Thank you for sharing, it made my day today.
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Old 18th Mar 2021, 11:54
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On the topic of machine tools in ancient civilisations, were these really necessary to make a device like this? I know that it's not at all comparable, but I stripped, cleaned and rebuilt an old grandfather clock not long ago. It was a bit rough and ready, nothing at all fancy about it, just a simple stained pine case and painted dial, with an apparent date of 1851 ( scratched into the backplate of the movement). There was little evidence of machining in any of the parts, most looked as if they had been fabricated by hand, with clear hand tool marks on the gears, shafts etc. Even the iron tapered pins holding the front and back plates tightly to the spacers looks as if they had been filed by hand, as did the square ends of the shafts driving the hands . It seems feasible that someone with a great deal of skill and patience, and only hand tools, to make all the parts needed for the antikythera device. Looking at the Clickspring videos it seems that he made things like the gear wheels just with hand tools, sawing out the discs and filing the teeth and central square holes

What puzzles me more is the metrology involved. The tolerances look to be pretty tight, and that means that whoever made it had some sort of standardised system of measurement, together with the ability to repeatedly measure dimensions to fractions of a millimetre We sort of take measurement for granted now, as anyone can buy a rule that's highly accurate (by ancient standards) for a few pence, and know that what they measure with it will be the same as someone using a similar rule anywhere else on earth. I wonder how the makers of these devices ensured they were all as accurate as they needed to be to function properly?
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Old 19th Mar 2021, 02:33
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It sounds like von Daniken was an utterly sociopathic conman, utterly without scruples. I recall being fascinated by Chariots, but it asked a lot of questions without answers, so was kind of a frustrating read as well.


Logical and factual errors

That writing as careless as von Däniken's, whose principal thesis is that our ancestors were dummies, should be so popular is a sober commentary on the credulousness and despair of our times. I also hope for the continuing popularity of books like Chariots of the Gods? in high school and college logic courses, as object lessons in sloppy thinking. I know of no recent books so riddled with logical and factual errors as the works of von Däniken.
— Carl Sagan, Foreword to The Space Gods Revealed
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Old 19th Mar 2021, 14:39
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I rmember from the TV many years ago someone demonstrating, in relation to the antikythera,
how it was possible to cut gears with simple tools. Sadly I do not remember how.
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Old 20th Mar 2021, 00:18
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Given the huge rings built for astronomy before the telescope, I wouldn't think making a dividing head would be too hard if one had to do it every day. I'd make a wheel, at least 10' in diameter, and then build a floor above it. Half a floor perhaps. The centre shaft would enter the workroom via a hole in the floor. Minions would turn the carefully divided big wheel, the quality of its build and its inertia would ensure the accuracy of the top turntable. It seems the division ratioes would be fairly routine for these geniuses. I wonder if they set flint chippings into bronze.
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Old 20th Mar 2021, 05:45
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Yeah, but 223 is prime.
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Old 20th Mar 2021, 08:59
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Hopefully Clickspring will get to complete his replica before too long, so we can all see how this amazing machine worked for real.
What techniques is he using?

I was struck by the comment, near the end if the video, that they had a project under way to investigate the techniques used in its construction as they were different to current methods.

e.g. Modern gear mechanism kept the gear trains separated vertically whilst the original had gears lying flat against each other’s with sliders between them.
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