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Precursors of Copernicus' heliocentric theory (johncarlosbaez.wordpress.com)
54 points by chmaynard 15 days ago | hide | past | favorite | 21 comments



> Aristarchus had come up with a heliocentric theory way back around 250 BC.

He notably did convincing calculations showing that the sun should be larger than Earth. However, this was not convincing enough for his opponents who argued notably that usually fire hardly remains in a fixed position. Also, if Earth was moving, it was hard to understand why there was no observed parallax on the stars at night. Actually, the first apparent proof that Earth was moving came after inventing instruments precise enough to observe parallax on far enough stars, in 1727, from James Bradley. It actually had different results from expectation, due to the finite speed of light [1].

Just after Aristarchus came also Seleucus of Seleucia [2]. He supposedly had a theoretical argument for heliocentrism, but it was lost.

[0]: https://en.wikipedia.org/wiki/On_the_Sizes_and_Distances_(Ar...

[1]: https://en.wikipedia.org/wiki/James_Bradley

[2]: https://en.wikipedia.org/wiki/Seleucus_of_Seleucia


I have recently been listening to the "The Complete History of Science" podcast [1]. I have not gotten to the Copernicus portion yet, but I really enjoyed the ancient Greek astronomy episodes (including the episode on Aristarchus).

[1] - https://thecompletehistoryofscience.buzzsprout.com/1916377/e...


> Earth was moving

They believed that the stars and Earth moved relative to each other, as far as I can tell. Why does it matter if they thought the Earth was moving or if they thought the stars were moving?

Maybe the math is simpler if it's the Earth.


The night sky obviously rotates, but that the earth translates relative to the stars is not so obvious. This was especially a problem because it was generally thought the stars were much closer than they actually are, because stars do have an apparent diameter to the naked eye (and through a telescope) which we now know to be an optical illusion (Airy Disk), and if you extrapolate this like with the planets they are either not that much further away or ludicrously big, like many solar systems, and parallax measurements were precise enough to at least put a high bound on their distance if the earth moved with respect to the stars, and gigantic stars wasn't a popular option.

For anyone interested in the topic of Copernicus' heliocentrism, I can recommend Arthur Koestler's 'The Sleepwalkers': https://en.wikipedia.org/wiki/The_Sleepwalkers:_A_History_of....

While it does contain some speculation that is, in my opinion, poorly grounded, overall it is very informative and does a good job of dispelling some of the oversimplified narratives that are told about e.g. Galileo's persecution by the Church. (Of course since this is HN I can't wait to hear somebody tell me about some oversimplified narratives due to Koestler!)

It's also just very written and full of amazing anecdotes - e.g. about how Kepler's mother was accused of witchcraft(!)


update: I consulted my copy of 'The Sleepwalkers' again, and I see that Martianus Capella is listed twice in the index.

Koestler claims that Martianus Capella's system, wherein Venus and Mercury orbit around the Sun, while the rest of the planets orbit around the Earth, is originally due to Herakleides (https://en.wikipedia.org/wiki/Heraclides_Ponticus, not to be confused with Heraclitus), a 4th century BC Greek philosopher. But I see that wikipedia links to an article [1] by Eastwood from 1992 that claims this to be a complete misattribution lacking any evidence. Link for the interested: https://adsabs.harvard.edu/pdf/1992JHA....23..233E.

[1] Eastwood, B.S., 1992. Heraclides and heliocentrism: Texts, diagrams, and interpretations. Journal for the History of Astronomy, 23(4), pp.233-260.


There's a currently ongoing anime called Orb: Movements of The Earth m. It depicts a compelling albeit fictionalized account of the rocky and often dangerous road faced by proponents of heliocentrism in the 16th century. Despite its fictional nature, the show makes reference to real thinkers such as Aristarchus and Occam, among others.


I understand that it isn't supposed to be accurate, given that it's based on a fictional country 'P' and based on a fictional church 'C', but the parallels are obvious to Polish/Catholic regime.

As someone living in a country where blasphemy lynching are still a part of life, and professors are made to renounce scientific beliefs[1], it feels disturbingly familiar to me.

[1]: https://www.dw.com/en/pakistani-clerics-cancel-theory-of-evo...


By fictionalized, I mean to say that certain aspects of the anime are inconsistent with historical record. I don't just mean the thinly-veiled references to Poland or the Catholic Church. For instance, one glaring anachronism is the Pear of Anguish. While the inquisitor in the show refers to his as a "prototype", no such device in any form existed until some two to three centuries later. The Pear in the show is a literary device that gruesomely establishes the stakes faced by the characters. It also operates as a visual metaphor for the Church's desire to silence dissent. But in no way or shape was it an instrument of torture in the 16th century.

Another point is that none of the characters in the show have existed in any capacity. They are not analogues of or stand-ins for the historical contributors to the heliocentric model. The characters' personalities and backgrounds, while consistent with the setting, are the inventions of the mangaka.

Now with all that said, the show excellently conveys the difficulty and threats faced by thinkers across the ages in the course of the Scientific Revolution. The historical circumstances were no less dire than what was depicted in the anime. But as a show, it still has more in common with romanticized depictions of men looking up at the night sky, such as in the Sarah Williams poem, the Old Astronomer, than it does with a thoroughly scrutinized biography of the astronomers of the era.

> As someone living in a country where blasphemy lynching are still a part of life, and professors are made to renounce scientific beliefs[1], it feels disturbingly familiar to me.

It pains me to know the spirit of the Inquisition is still present in the 21st century.


> By fictionalized, I mean to say that certain aspects of the anime are inconsistent with historical record. I don't just mean the thinly-veiled references to Poland or the Catholic Church. For instance, one glaring anachronism is the Pear of Anguish. While the inquisitor in the show refers to his as a "prototype", no such device in any form existed until some two to three centuries later. The Pear in the show is a literary device that gruesomely establishes the stakes faced by the characters. It also operates as a visual metaphor for the Church's desire to silence dissent. But in no way or shape was it an instrument of torture in the 16th century.

I can somewhat empathize with this—the torture that did exist at the time (crushing someone to death, breaking their bones on the wheel, Schwedentrunk, flaying people alive, and far too many other practices I'd like to avoid mentioning at all) I would be more than happy to never see visualized. The historical record is important, but sometimes inaccuracies are useful in conveying symbolic power and threats. Some translation and interpretation is always necessary if you want to produce a coherent narrative.

Realistically, with history-as-entertainment, if you can capture some things well you're doing far better than many even try to. I love Ridley Scott but his depictions of history are far more of a discussion about how the west views itself today rather than even trying to translate something from the time to today. Which is fine! It's entertainment. And many do far better than he does.


> The historical record is important, but sometimes inaccuracies are useful in conveying symbolic power and threats. Some translation and interpretation is always necessary if you want to produce a coherent narrative.

Translation and interpretation is something I have no problem with, as these are not flaws of the work. However, I'm of the view that valuing a work of art requires being able to scrutinize it, while still being able enjoy it. It doesn't do one any favors to accept false facts. There are several works that establish "truths" compelling enough to be credible for someone without the background knowledge. To those who fail to question if something is true, art becomes artifice and fiction becomes indistinguishable from reality.

> Realistically, with history-as-entertainment, if you can capture some things well you're doing far better than many even try to.

> I love Ridley Scott but his depictions of history are far more of a discussion about how the west views itself today rather than even trying to translate something from the time to today.

That you're able to appreciate the ideas being conveyed and the motives behind doing so is precisely the reason a sense of scrutiny is necessary. Kingdom of Heaven is definitely an example of a movie that provides a retrospective/revisionist examination of the Crusades rather than an historical one. Such an insight can't obtained from mindlessly watching it as a "realistic Lord of the Rings".

While these things might be discussed in interviews, behind-the-scenes featurettes, or in the audio commentary, public exposition of these aspects of storytelling is rarely afforded to anime or manga.


Apologies, didn't mean to criticise you, I just wanted to gush over the show.

Acc to reddit, the show's characters are proxies for famous scientists of the era, like Kepler, Copernicus etc. Not their lives, but they seemed to be mapping their theories to characters in that way.


There's no need to apologize. I didn't take your statements as criticism I simply assumed you were confused as to what I meant. "Fictionalized" often has a negative connotation, and I only wanted to clarify my usage of the term was in the strictest and most technical meaning.

Nevertheless, It's certainly a show worth gushing over. It's a well-done work of art.

> Acc to reddit, the show's characters are proxies for famous scientists of the era, like Kepler, Copernicus etc. Not their lives, but they seemed to be mapping their theories to characters in that way.

The relationships between some of the characters are reminiscent of the real-life relationship between Tycho Brahe and Johannes Kepler as noted in a biography called The Nobleman and the Housedog by Kitty Ferguson. You might find it interesting.

If you like this anime, you might enjoy Spice and Wolf. Although, since you're on Reddit, you might have already seen either adaptation.


Haven't seen the anime, but at the time of Copernicus Poland wasn't THAT Catholic. I mean it was Catholic, but it wasn't extermist about that compared to Western Europe.

Polish Kingdom had a long-standing conflict against Teutonic Knights over Prussia (which is where Copernicus lived). Prussian Confederation joined Poland to be defended against Teutonic Knights and Copernicus even participated in defence of Olsztyn castle against them.

Czech hussites (protestants before Luter) participated in wars against Teutonic Knights on the Polish side, and Polish king supported them to some degree against Catholic crusades.

Few decades before Copernicus Poland even sent a delegation to Council of Constance defending the right of pagans no to be invaded in crusades and supporting Lithuanians against Teutonic Knights. The guy making this argument was Paweł Włodkowic who taught in Kraków Academy before Copernicus studied there.

Also - Polish nobility was starting to embrace reformation in 16th century and even forced Polish kings to give them guarantees of religious freedom. https://en.wikipedia.org/wiki/Warsaw_Confederation

TL;DR: Poland was pretty tolerant for the time. It became hardcore Catholic after counterreformation.


I made a mistake in the timeline of Orb: On the Movements of the Earth. It begins in an unspecified year of the early 15th century, not the 16th, and thus several decades before Copernicus and his subsequent discoveries. It does, however, stretch across multiple periods of time.

All the same, thank you for the information as it provides significant context for the setting and for what could be a future plot point should the show decide to exploit it.

As I've mentioned in another thread in this comment section, there are a number of fictionalizations in the show that might, for lack of better phrasing, "stand out" to those who are more familiar with the history of the setting and era. But in spite of all that, it has an excellent story and the characters roles are very well performed. It's a real gem from studio Madhouse and I have no reservations in recommending it.


Is it true you still have to sign halafnama against Ahmedis to get your PhD?


To get your phd? That I don't know, but to get your passport, yes.


Fitting with epicycloids is a form of Fourier analysis/synthesis and such curves can approximate any smooth closed curve -- universal approximators.

With deep NNs being used for Physics research to fit data it does make me wary if we are getting into epicycles again.


"Sometime between 410 and 420 AD, Martianus Capella came out with a book saying Mercury and Venus orbit the Sun, while the other planets orbit the Earth!"

Was there ever serious considerations of Capella's model? How do we know it is wrong? For instance, Tycho's model was found to be wrong because, if I remember correctly, some orbits crossed each other and that ruined the theory. Is there such a contradiction with Capella's model?


> How do we know it is wrong?

Well, for one thing, we have now sent assorted space probes to the other planets, something that requires precise knowledge of their current and future positions, something that cannot be done without an accurate model of their orbits.

Are you seriously suggesting that Mars, Jupiter et al orbit the earth rather than the sun, or am I badly misreading your comment?

> Was there ever serious considerations of Capella's model?

TFA discusses at length how that model was quite popular in Europe for centuries.


I highly recommend this channel. The human story behind the discovery.

Copernicus: The Man Who Made A God

https://www.youtube.com/watch?v=OgVOhbk8H1c




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