[HN Gopher] The Antikythera mechanism - 254:19 ratio
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The Antikythera mechanism - 254:19 ratio
Author : 082349872349872
Score : 148 points
Date : 2024-12-15 18:46 UTC (1 days ago)
(HTM) web link (leancrew.com)
(TXT) w3m dump (leancrew.com)
| zefhous wrote:
| I'm just here to fulfill the Hacker News rule that any post
| mentioning the Antikythera Mechanism must have a comment linking
| the excellent Clickspring build videos.
|
| https://youtube.com/playlist?list=PLZioPDnFPNsHnyxfygxA0to4R...
| beeforpork wrote:
| Thank you! I was waiting for it so I could click on it again.
| :-)
| mattbillenstein wrote:
| Excellent videos - and the one thing that sticks with me was
| the speculation that watchmaking and the processes that it
| requires eventually leads to the type of technology we have
| today. I think the line goes if the greeks of that era had been
| allowed to progress another 300-400 years, they may have been
| able to land on the moon...
| etrautmann wrote:
| This is why I love HN, thanks for sharing
| sgt101 wrote:
| https://www.bbc.co.uk/programmes/m0024x0g
|
| Up to date and with a very good discussion of the 254:19 gearing.
|
| Also much more detail on the history of the mechanism.
| Alex3917 wrote:
| If you're in Athens, the Herakleidon museum has not only an
| exhibit about this, but about all sorts of other advanced Greek
| technology: coin-operated vending machines, drink-serving robots,
| water-powered telegraphs, etc. While this specific device may (or
| may not) have been a one-off, it's undeniable that ancient Greece
| was basically the real-life version of a Steampunk-based society.
| (With the caveat that ancient Persia probably had similar
| technology at one point also, but most of that has since been
| destroyed by the British and others throughout history.)
| hyhconito wrote:
| Oh damn it. Missed that one entirely. I will have to come back
| again.
| jcims wrote:
| Same!!!
|
| I just asked chatgpt "Based on what you know about me, what
| do you think I would be interested in seeing in Athens?"
|
| The Herakleidon Museum was third on the list. May have to try
| this again in the future.
| hyhconito wrote:
| Never thought of using it for that.
|
| Annoyingly I'm in Athens right now but flying back tomorrow
| way too early to sneak a visit in :(
| jcims wrote:
| That airport is a bit of a haul. :/
| hyhconito wrote:
| Was even worse last week. Got off plane and metro was on
| strike.
| dwighttk wrote:
| what does chatgpt know about you?
| fragmede wrote:
| As you chat with it, it'll pick up random details from
| conversations (eg owns a cat) and stick it into a limited
| memories folder, which can be manually inspected and
| cleared out as desired.
| Terr_ wrote:
| > water-powered telegraphs
|
| This phrasing oversells it a bit too much: The water wasn't a
| power source and there was no long distance movement of it.
|
| They signaled between users with the light of a burning
| handheld torch, and the duration of the light corresponded to
| predefined messages.
|
| Water was used at each end for independent stopwatches, to
| measure the duration of the light. It's easy to imagine an
| equivalent system using sand hourglasses.
|
| https://en.m.wikipedia.org/wiki/Hydraulic_telegraph#Greek_hy...
| hyhconito wrote:
| Ha literally just saw that this morning in the National
| Archaeological Museum in Athens! Lurking here paid off. A good
| read.
| meew0 wrote:
| > I've always liked blogging about calendrical things, but I
| don't remember doing anything on the Metonic cycle before. If I
| had written faster, I could've published it on Friday the 13th.
| Too bad.
|
| On the other hand, you published it during a full moon. That's at
| least slightly appropriate given the subject matter :)
| casenmgreen wrote:
| I was living in Athens, and visiting the museums, and I had no
| idea - I walked around a corner in the National and pow - the
| Mechanism, _THE_ Mechanism, was there, _right in front of me_.
|
| _WOW_.
|
| Also, Elgin marbles need to be returned. Parthenon is defaced by
| their absence.
| sneak wrote:
| They're not putting them outside again; they'd be inside in the
| Acropolis museum. The Parthenon (blown up as it is) would still
| be missing them.
| euroderf wrote:
| Speaking of which, where's the apology from Turkiye for
| storing ammo there ?
| globnomulous wrote:
| Elgin marbles don't need to be returned and are safer in the
| UK.
| lioeters wrote:
| > In 2021, UNESCO concluded that the UK government had an
| obligation to return the marbles and called upon the UK
| government to open negotiations with Greece.
|
| > Asked about the possible return of the Marbles, the British
| Culture Secretary, Michelle Donelan replied: "I can
| sympathise with some of the arguments but I do think that is
| a very dangerous and slippy road to embark down."
|
| > ..Fulfilling all restitution claims would empty most of the
| world's great museums - this has also caused concerns among
| other European and American museums.
| atmosx wrote:
| > My sketch of the Sun-Earth-Moon system assumes a heliocentric
| solar system, something that wasn't known to the Greeks of the
| first century BCE.
|
| I am not sure this is entirely accurate. According to Wikipedia:
|
| > The notion that the Earth revolves around the Sun had been
| proposed as early as the 3rd century BC by Aristarchus of
| Samos,[1] who had been influenced by a concept presented by
| Philolaus of Croton (c. 470 - 385 BC). In the 5th century BC the
| Greek philosophers Philolaus and Hicetas had the thought on
| different occasions that the Earth was spherical and revolving
| around a "mystical" central fire, and that this fire regulated
| the universe.[2] In medieval Europe, however, Aristarchus'
| heliocentrism attracted little attention--possibly because of the
| loss of scientific works of the Hellenistic period.[b]
|
| Source: https://en.m.wikipedia.org/wiki/Heliocentrism
|
| Contrary to the recent revisionist version of the "dark ages",
| they were pretty dark if you were a Greek of the Hellenistic
| period, an Athenian 5th century BC or a Roman the next 500-800
| years. Loss of philosophical (locked in monasteries) and
| technical knowledge is common and Heliocentrism or the blood
| circulation system (Egyptians during the Ptolemy era had
| knowledge comparable to the one we will acquire again 18th
| century) are two prime examples.
| arp242 wrote:
| You can argue semantics on this, but "wasn't known to the
| Greeks of the first century BCE" is basically accurate, or
| certainly "accurate enough" for this context. All of the
| heliocentric writers were basically little more than "this idea
| some guy had", and geocentric views as described by e.g.
| Aristotle were dominant.
| globnomulous wrote:
| If that's true, then by the same reasoning you're also saying
| that heliocentrism wasn't known to the Europe of (insert any
| time before the mid 1600s), because it was little more than
| an idea some guy had, not dominant or accepted.
|
| But nobody would characterize the history of the science that
| way, because it simply isn't true. "Wasn't known to the
| Greeks" is inaccurate, particularly in its historical
| context, since science and philosophy were often "little more
| than 'this idea some guy had.'"
| noncoml wrote:
| Does geocentric go hand in hand with flat earth?
|
| Because it was pretty common scientific knowledge that earth
| was round back then. A knowledge that got lost during the
| dark ages.
|
| For example: In the third century BCE , Eratosthenes, a Greek
| librarian in Alexandria , Egypt , determined the earth's
| circumference to be 40,250 to 45,900 kilometers (25,000 to
| 28,500 miles) by comparing the Sun's relative position at two
| different locations on the earth's surface.
| zardo wrote:
| > A knowledge that got lost during the dark ages.
|
| Any examples of that? I've heard it called a myth.
| atmosx wrote:
| Google "the Galileo Affair".
| zardo wrote:
| I meant specifically that the Earth is roughly ball
| shaped.
| ithkuil wrote:
| I suggest you read about it again. It was about geo-
| centric vs helio-centric models. It was not about flat vs
| globe.
|
| The geo-centric model assumed the earth was spherical but
| it didn't rotate or otherwise move.
| atmosx wrote:
| True, I didn't follow the thread closely, my bad.
| landswipe wrote:
| This guy Sagan's...
| gattilorenz wrote:
| > Egyptians during the Ptolemy era had knowledge comparable to
| the one we will acquire again 18th century
|
| Citation needed, especially given the "comparable".
|
| The "dark age's revisionism" afaik doesn't claim that there was
| no loss of technical and philosophical knowledge (not that the
| average roman soldier would normally be a philosopher...), but
| that it's limited to a few centuries. By the 12th and 13th
| century it's very difficult to speak of dark ages.
| atmosx wrote:
| Thisnlink is not the one that I had in mind - a Wikipedia
| link that talks specifically about blood circulation details
| explained in ancient Egyptian mummification texts
| rediscovered in Europe during that time - but in some sense
| it is more accurate[^1].
|
| [^1]: https://pmc.ncbi.nlm.nih.gov/articles/PMC4290745/
| analog31 wrote:
| Reminds me of finding a pair of gears in a box of lathe
| accessories, with 50 and 127 teeth.
| mauvehaus wrote:
| For anyone who isn't aware: that's the pair of gears with the
| smallest number of teeth (and by extension, largest teeth for a
| given size pair of gears) in the ratio of 2.54:1.
|
| As I'm not a machinist, I'm not going to try to explain just
| where in the geartrain you'd use this pair to convert your
| metric machine lathe into a US customary lathe, but that's what
| they're for.
| analog31 wrote:
| There's typically a gear train that communicates the rotation
| of the spindle to the threading mechanism. This is so that
| you can turn a precise number of threads per unit length, and
| to take multiple passes to reach the desired thread depth.
| There's a multi-ratio gearbox that sets the thread pitch.
|
| The 2.54 ratio lets you turn metric threads on a US machine,
| with the help of tables in the manual for how to set all of
| the levers. Machinists hate it, and these days will prefer to
| buy a die for the occasional threading job.
| mikewarot wrote:
| I think if I had to do metric threads often, I'd switch to
| an electronic leadscrew, like the one from Clough42.[1]
|
| [1] https://github.com/clough42/electronic-leadscrew/wiki
| mauvehaus wrote:
| The remaining problem is that metric threads are specified
| by the mm between peaks, whereas US customary threads are
| specified by threads/inch.
|
| It's not immediately obvious to me (not a machinist) that
| the 127/50 ratio gets you the ability to cut metric threads
| without a mess of other head-scratching because you're now
| dealing with period instead of frequency.
| analog31 wrote:
| Indeed, the charts for cutting metric threads are
| complex, and I'm not sure all of the standard pitches are
| even possible.
|
| The lathe that I use hasn't had its threading gears
| installed in ages.
|
| A weird historical tidbit is that after WWII a couple of
| standards emerged for bicycle parts in Europe, where they
| used metric diameters and inch thread pitches.
| mauvehaus wrote:
| The Italian bottom bracket threading standard is
| completely insane. Like, how do you even cut that, and
| why would anyone come up with that in preference to
| literally anything else?
| analog31 wrote:
| The only thing I can imagine was a supply of American
| machine tools from the rebuilding of Europe after a WWII.
| You can always cut any diameter, only the thread pitches
| are ruled by the capabilities of the lathe.
|
| Also, left handed threads involve their own issues since
| the spindle chuck wants to unscrew itself.
| robertlagrant wrote:
| Hah - I watched that Veritasium video the other day.
| hoseja wrote:
| I once heard that the mechanism was too fine/the gear train too
| large that it could not possibly actually work without stripping
| the gears or seizing due to friction.
| floxy wrote:
| Does anyone know if Clickspring ever finished making a copy of
| the mechanism? Seems like the last update was from ~2 years
| ago.
|
| https://www.youtube.com/watch?v=ML4tw_UzqZE
|
| https://www.youtube.com/@Clickspring/videos
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(page generated 2024-12-16 23:02 UTC)