Researchers home in on possible “day zero” for Antikythera mechanism
arstechnica.com
arstechnica.com
> “This is a very specific and unique date,” Voulgaris said. “In one day, there occurred too many astronomical events for it to be coincidence. This date was a new moon, the new moon was at apogee, there was a solar eclipse, the Sun entered into the constellation Capricorn, it was the winter solstice.”
That's only if you consider them globally, as a solar eclipse (especially a partial one) covers only a small part of Earth. A single particular location e.g. Ancient Greece would see a full solar eclipse roughly every 360 years and some kind of partial eclipse roughly once a century, so that's quite a big difference, making a solar eclipse exactly during the winter solstice in Greece a very rare once in a 10000 year event.
You can’t really work it like that. If I roll a dice and get a 6, you’d maybe say that this might be a coincidence because there’s 6 possible outcomes, with 1 chance of a , so a high chance it was a coincidence. But there’s 365 days in a year, and 200 countries in the world. So actually the fact that I rolled a 6 on this day and in this country has a 1:73000 chance and clearly can’t be just a coincidence. Now clearly something must be up, and I must be cheating at dice!
Once a day, you roll a dice with 3,650,000 sides. Only one of them shows a solar eclipse. On the day of the 200-year solar eclipse, the dice shows the solar eclipse side. Not a coincidence.
You're incorrectly applying a basic abstract statistical principle to a complicated real-world situation.
Slightly tangential, but the whole pre/post-Copernicus narrative seems unlikely to be true to me. At least I find it difficult to believe it wasn't until the 16th century that someone worked this out and everyone prior was of some woefully mistaken (yet suspiciously Christian-aligned) view that the Earth was the center of the universe.
And even with Copernicus's insight, he was still missing some key details which made it harder to believe he had the general idea right. Copernicus modeled the solar system using circular orbits, not elliptical orbits. To fit the observed data to this model, he needed epicycles, just as the geocentric model required.
We even have record of someone reasoning this out of simple observations nearly 2000 years prior. This suggests to me it was known (at least by intellectuals) for a very very long time.
If I'm not mistaken, there is quite a bit of evidence that they knew the correct model was with the Sun in the center and they only used epicycles because it was easier to calculate with the tools they had (compass etc).
EDIT: I think the argument is at section "10.12 Seleucus and the Proof of Heliocentrism" of the book.
Also, a heliocentric model still requires epicycles if the orbits in the model aren't elliptical.
In particular, it removed the need for a particular type of epicycle called an Equant. Ironically, the Equant somewhat resembles Kepler's second law, meaning it arguably is a better approximation of reality than Copernicus' circles-only Heliocentric model.
I'm not sure I can find the exact book. There's, like, so many books about Copernicus on Amazon. This is my best guess: https://www.amazon.com/Book-Nobody-Read-Revolutions-Copernic...
There were certainly heliocentric models of the universe proposed before Copernicus, but Copernicus' one was the more well-developed. In some cases we don't even have a model, as such, just some third-hand accounts mentioning that someone thought the sun must be in the center of the universe.
I suspect the most famous example of that is Aristarchos of Samos, for whose heliocentric theory we only know via a very brief and poorly detailed passage in Archimedes' The Sand Reckoner:
You [King Gelon] are aware that "universe" is the name given by most astronomers to the sphere, the centre of which is the centre of the earth, while its radius is equal to the straight line between the centre of the sun and the centre of the earth. This is the common account (τά γραφόμενα), as you have heard from astronomers. But Aristarchus brought out a book consisting of certain hypotheses, wherein it appears, as a consequence of the assumptions made, that the universe is many times greater than the "universe" just mentioned. His hypotheses are that the fixed stars and the sun remain unmoved, that the earth revolves about the sun on the circumference of a circle, the sun lying in the middle of the orbit, and that the sphere of the fixed stars, situated about the same centre as the sun, is so great that the circle in which he supposes the earth to revolve bears such a proportion to the distance of the fixed stars as the centre of the sphere bears to its surface.
https://en.wikipedia.org/wiki/Heliocentrism#Aristarchus_of_S...
So it's not that there weren't heliocentric models of the universe before Copernicus, just that they didn't really catch on, I guess.
My point was maybe this had something to do with why it "didn't really catch on." Given how viciously the idea was attacked by the Roman Inquisition as being heretical it was probably not the first time the church encountered the concept.
IIRC, monks were the predominant scribes in the western world pre-printing press. If intellectual ideas didn't conform to religious canon they could've theoretically been nearly completely erased via censorship only to be "newly discovered" by Copernicus etc.
I don't reckon it was an easy job to be an astronomer in those days...
The heliocentrism model was only proven by the successive efforts of Kepler and Newton. Kepler made it more accurate by formulating his laws of motion (which allow for an elliptical motion and eliminate the last need for epicycles), and Newton showed how Kepler's laws of motion could be derived from F = GMm/d^2. Kepler was a contemporary of Galileo, and Newton came later.
Regarding the treatment of Galileo, Galileo was on very good terms with the Roman Church until he openly insulted geocentrism proponents in a book, and presented the heliocentrism theory as a proven fact. The book is also notable for presenting an incorrect theory of tides, not giving credit to his contemporaries, omitting the more accurate and profound theory of Kepler, and attacking a strawman that nobody was defending (in the sense that the favoured model of the time was Brahe's, and not the complicated epicycles model that Galileo was attacking).
It should be noted that the Ancient Greeks did consider the idea of the Earth moving, but there was no empirical evidence for it. Specifically no parallax as even Aristotle wrote in De Caelo (II.14):
> Again, everything that moves with the circular movement, except the first sphere, is observed to be passed, and to move with more than one motion. The earth, then, also, whether it move about the centre or as stationary at it, must necessarily move with two motions. But if this were so, there would have to be passings and turnings of the fixed stars. Yet no such thing is observed. The same stars always rise and set in the same parts of the earth.
* http://classics.mit.edu/Aristotle/heavens.2.ii.html
* https://en.wikipedia.org/wiki/On_the_Heavens
Bradley noticed stellar aberration in ~1728:
* https://en.wikipedia.org/wiki/James_Bradley
Giuseppi Calandrelli finally directly measures parallax in α-Lyrae in 1806.
In general, the way I understand it is that most of what the ancients believed about the universe was based on empirical observations. They didn't just come up with some arbitrary theory, they had observations and they were trying to explain them. The epicyclical model persisted all the way to Copernicus (whose model also had epicycles) just because it was so good at predicting future observations.
I think their main axiomatic assumption that was based on their metaphysical beliefs, rather than actual observations, was the assumption that the luminaries must move on circular orbits. Again, to my understanding, they had a mechanistic view of the universe that demanded order and symmetry, and they just couldn't imagine how a planet would move in any other orbit than a circle- hence why they were mystified by the apparent "retrograde" motion of the planets and had to come up with epicycles to model it.
The combination of their axiomatic belief in a mechanistic universe and the limited observations they could make with the naked eye conspired to keep them from a better model.
A mechanistic view of the universe, taken up later by Christianity, is what allowed science (in the modern sense) to be created. Contrast it with a worldview in which phenomena occurred because of the will(s) of deity(s).
* https://en.wikipedia.org/wiki/Naturalism_(philosophy)#Provid...
Things have causes with-in themselves. If you deny secondary causation you tend to fall into Occasionalism.
The path is the church did accept we watch from earth but every heaven body revolve around the sun except us. Catholic use this model and very accurately beat the Muslim and the Hans (do not want to use chinese as the fight started in yuan dynasty, Mongolian and Tibetan etc are not Hans) in the Far East precisely of these tables based on actual observation.
This comes from a guy x then his student called kepler pointed out … Newton use Kepler not just a Copernicus model only.
The key is Copernicus is only partially right as the orbit is NOT as he said. It is not circular. and in fact he did not have the details and hence might as well not exist and might not affect the history. That is why his book is ok for many decades after publishing. It is only of the models. And not exactly right like others. the actual path is those who have calculation and a detailed accurate projection which Copernicus did not have.
That revolve around the earth model worked. Not Epicircie.
In truth even today if you observe the sky from earth you cannot just have a solar model. You have the earth factor as well (like the earth minor movement around its axis abd hence North Star change from vega to polar then back to vega). Just solar modal is not right.
Now whilst the looking thru telescope did disturb the worldview. It does not matter.
And it is the attitude of Galileo that is more an issue. The pope is his friend you know well before he is a pope. Teasing him as a joker does not work in those days.
I am not saying C and G is totally wrong. I just say if they were more careful (like C publish his only after his death). And G accept the practical model of using sun as a centre based on actual observation and do not write satire … instead proposing a model that incorporates elliptical orbit, earth role etc but everything revolve around the sun except the earth (then do something about it gradually).
Anyway that is not the history of hero we read. We want drama. We want …
However, the main problem with most of the achievements of the Ancient Greek Philosophy is that, unlike for logic and mathematics, for theories about natural objects they did not have good methods to determine which of several alternative theories is right.
So in the natural sciences there are a lot of questions about which some Ancient Greek philosophers have guessed the correct answer while others have guessed wrong.
Now we know who was right and who was wrong, but at that time this was non-obvious and in most cases the popularity of the alternative explanations was determined more by the rhetoric skill of their supporters than by their agreement with the observations of nature.
Even when the agreement with observations was actually checked, the methods of measurement were seldom precise enough to allow a non-ambiguous decision between 2 theories.
This also applies to the heliocentric theory and the geocentric theory. Both theories had their supporters, but in the end the geocentric theory became the main theory for almost 2 millennia because it happened to be the theory chosen by Hipparchus and then improved by Ptolemy.
Ptolemy made a more detailed kinematic model of the movements of the bodies in the Solar System, which agreed better with the observations of the planets than all the earlier models, so those were abandoned until Copernicus revived the heliocentric model.
I'm skeptical the previous heliocentric ideas were truly organically abandoned. More on that in my other comment: https://news.ycombinator.com/item?id=30991734
In fact, at the time the evidence for many models was equally strong. So, based on the limited available evidence of the day it actually would have been incorrect to believe too strongly in any model, even the one that we now know to be better than the others.
"Archimedes then estimated an upper bound for the number of grains of sand required to fill the Universe. To do this, he used the heliocentric model of Aristarchus of Samos. The original work by Aristarchus has been lost. This work by Archimedes however is one of the few surviving references to his theory...."
One key element is that heliocentric models where just not as good at making predictions. It took new data for them to finally get to a dominating position.
That was because we do not perceive the Earth moving, but we see the stars move. Nobody could answer objections like why we don't go flying off the Earth if it's spinning. Yet any idiot could take a ball, put a rock or something on it, spin the ball and show you what happens. Why is the Earth itself somehow different? It's like how they knew that stellar parallax should exist, but nobody could measure it, which caused heliocentrism to be lacking evidence for quite a long time because the stars are just that far away that it's tiny.
If you go to the average person now, I think you'll find that most people who accept all this science can't even give full explanations for why.
A heliocentric model wasn't simpler and more obvious until Kepler introduced elliptical orbits, doing away with epicycles in the heliocentric model. Crucially, elliptical orbits didn't work for the Ptolemaic model. Suddenly, a heliocentric solar system seemed much more elegant and likely.
I'm sure it must have occurred to more than one back then that the planets go around the Sun in elliptical orbits. The Antikythera mechanism even models the elliptical orbit of the moon around the Earth, so it's not farfetched that they could have figured out the rest.
However, convincing all the right "authorities" of the copernican view back then would have been culturally very difficult.
Solar eclipses by definition happen on a new moon, so that's not much of a coincidence. "The sun entering capricorn" is just arbitrary bullshit, not a precise measurement, but surely it has to either always fall on the solstice or never? Eliminate those duplicates, and it is looking a lot less impressive.
Since we have only one device like this and it was found under rare circumstances (shipwreck), it seems like you could do a Bayesian analysis to get a rough order of magnitude estimate of how many of these were built.
https://www.scientificamerican.com/article/an-ancient-greek-...
I assume that the average person who encountered one would have been very impressed, so I find it really surprising that we don't have more texts that at least mention the existence of these devices.
Very few people were in the circles of the highly educated. With many other intricate, rare instruments throughout history, the case is that they were commissioned by the extraordinarily wealthy from the most notable scholars and inventors
There is a nice serie of videos by Clickpring partially building a copy. He used tools that he guess were available at that time. It's more a good guess by a current expert than a 100% accurate historically based list of tools, but it looks like a good guess.
Main part, building the device: https://www.youtube.com/playlist?list=PLZioPDnFPNsHnyxfygxA0...
More details about the tools: https://www.youtube.com/playlist?list=PLZioPDnFPNsGnUXuZScwn...
However, maybe that attribution is similar to attributing the light bulb to Edison. We don't know who Archimedes might have been working with, who's shoulders he might have been standing on, etc.
It seems similar to a clockwork mechanism and there are some wonderful explainer pages on mechanical clocks[1]. Something like this for the Antikythera mechanism would be really helpful.
To put it simply: No.
To put it in more words: The most recent and accurate model of how it is expected to have worked is from just last year [0]. We have had working models produced in the real world, and have had computer simulations as well, but they have involved best-guesses at some parts here and there. However, even that model has a major flaw - it depends on the Greeks having access to a technology (hollow tubing of a particular accuracy), that we have no evidence that they did.
[0] https://www.theguardian.com/science/2021/mar/12/scientists-m...
Any chance someone engraved it on the device after it was built?
Alternatively, why does something engraved on the front necessarily have to be involved in the device calibration? Maybe they put that on there simply because it's a yearly important event that is related to astronomy?
irregardless (adj.)
an erroneous word that, etymologically, means the opposite of what it is
used to express; probably a blend of irrespective and regardless, and
perhaps inspired by the colloquial use of the double negative as an
emphatic. [1]
Start with the auto-antonyms: https://en.wikipedia.org/wiki/Auto-antonym
* Cleave can mean "to cling" or "to split apart".
* Clip can mean "attach" or "cut off".
* Dust can mean "to remove dust” (cleaning a house) or "to add dust" (e.g. to dust a cake with powdered sugar).
* Fast can mean "without moving; fixed in place", (holding fast, also as in "steadfast"), or "moving quickly".
* Ravel can mean "to separate" (e.g. threads in cloth) or "entangle".[11] Sanction can mean "approve" or "penalize".
* Table can mean "to discuss a topic at a meeting" (British English) or "to postpone discussion of a topic" (American English).
If you've not seen it, I highly encourage this 6 minute take by Stephen Fry on Language:
https://www.youtube.com/watch?v=J7E-aoXLZGY
And besides, while you may be honing a blade or skill, my Homing Pigeon is homing in on home.
"Honing" is more metaphorically akin to polishing. To hone a skill means to practice at it.
So is Merriam-Webster now going to say "here, here" is equivalent and acceptable?
Legalizing a hearing mistake is not the same thing as adjusting to usage changes.
https://books.google.com/ngrams/graph?content=home+in%2C+hon...
It's "home in." Merriam-Webster's next change will probably say "it's a doggy-dog world" is acceptable.
I might have to steal your idea.
Robots were so prevalent in the imaginative and material culture of the Greek-speaking world that they were seen as emblematic of Hellenistic culture by others. Buddhist legends focused on north-eastern India from the fourth and third centuries BCE recount the army of automata that guarded Buddha’s relics, built with knowledge smuggled from the Graecophone world. In one version, which features both killer robot-assassins and robot-guardians, a young man travels in disguise to the land of the Yavanas (Greek speakers) to learn the art of automaton-making, a secret closely guarded by the yantakaras (automaton makers) there, knowledge that he then steals to make the artificial guards. We find stories of automatic warriors guarding the Buddha’s relics in Chinese, Sanskrit, Hindu, and Tibetan texts. Additionally, mechanical automata also appear elsewhere in the Chinese historical record: for example, at the court of Tang ruler Empress Wu Zhou (c.624–705 CE).
https://thereader.mitpress.mit.edu/the-ancient-history-of-in...
Nowdays, we're better known for our army of civil servants guarding state pensions :/
Dr. A. Medes, the project's head researcher from Kythera University said, "the real breakthrough was decoding the instruction set of the RISC Antikythera in order to understand what the ancient JTAG interface was telling us".
Google verified the device no longer has Android security updates available.