Name: Mysterium cosmographicum
ISBN: 9780913870648

What Hacker News says

zogrodeaJul 2024

Reading The Sleepwalkers by Arthur Koestler may be interesting for you. Science and cosmology has progressed tremendously because of people like Kepler who have had right conclusions despite incorrect methods.

One relevant excerpt:

“A phrase seems to have been humming in his ear like a tune one cannot get rid of; it crops up in his writings over and again: there is a force in the sun which moves the planet, there is a force in the sun, there is a force in the sun. And since there is a force in the sun, there must exist some beautifully simple relation between the planet’s distance from the sun and its speed. A light shines the brighter the nearer we are to its source, and the same must apply to the force of the sun: the closer the planet to it, the quicker it will move. This is his instinctive conviction, already expressed in the Mysterium Cosmographicum; but now, at last, he has succeeded in proving it.

In fact he has not. He has proved the inverse ratio of speed to distance only for the two extreme points of the orbit; and his extension of this ‘Law’ to the entire orbit was a patently incorrect generalization. Moreover, Kepler knew this, and admitted it at the end of the thirty-second chapter,18 before he became airborne; but immediately afterwards, he conveniently forgot it. This is the first of the critical mistakes which ‘as if by a miracle’ cancelled out, and led Kepler to the discovery of his Second Law. It looks as if his conscious, critical faculties were anaesthetized by the creative impulse, by his impatience to get to grips with the physical forces in the solar system.“

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jpreteMay 2024

He did attempt to explain why. Wikipedia: "On 4 February 1600, Kepler met Tycho Brahe....Tycho guarded his data closely, but was impressed by Kepler's theoretical ideas and soon allowed him more access. Kepler planned to test his theory from Mysterium Cosmographicum based on the Mars data, but he estimated that the work would take up to two years (since he was not allowed to simply copy the data for his own use)."

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throw0101bDec 2023

> He was right.

Monkeys throwing darts can also (just happen to) be "right" when picking stocks that do well in the market. Galileo had as much evidence in believing Copernicus was right as the monkeys.

If he had simply stuck to simply arguing both sides of an hypothesis in his Dialogue, which he was asked to do by the pope in the first place, it would have saved everyone a lot of trouble. Heck, Kepler's stuff was already around for decades, and Galileo completely ignored it (along with Tycho):

* https://en.wikipedia.org/wiki/Dialogue_Concerning_the_Two_Ch...

If you want to argue 'for science' then Galileo is not a good example: the only thing he just happen to be right about was that the sun was the centre of things, whereas everything else in the Copernican system (including epicycles) was just as messy as in Ptolemy. There was no practical reason to switch systems, and no evidence to think it was correct.

At the end of the day the person who actually got things right was Kepler, and he kept plugging away at the problem because of this belief that the physical world reflected the spiritual realm (KGW XIII, letter 23, 35; 1595)

> In this way, then, the Sun, itself at rest in the middle and yet the fount of motion, carries the image of God the Father and creator. For what creation is to God, motion is to the Sun. Moreover, it moves [the planets] in a fixed place, as the Father creates in the Son. Unless the fixed stars offered a place, thanks to their motionlessness, no movement could exist. I defended this axiom while still in Tübingen. The Sun distributes motive virtue through the medium space, in which the planets are found: just as the Father creates by spirit or by the virtue of His spirit. And from the necessity of these presuppositions, it follows that motion is in proportion with distance.

See Kozhamthadam's "The Religious Foundations of Kepler's Science" and "Theological Foundations of Kepler's Astronomy" by Barker and Goldstein.

Going further, one needs to believe in certain metaphysical assumptions before you can even start doing what we know call science:

* https://en.wikipedia.org/wiki/Naturalism_(philosophy)#Provid...

There were plenty ideas floating around at the time, but ideas are cheap. Galileo certainly made important improvements to telescope technology, but his efforts in moving forward new models (specifically Copernican) were a dead end, and he made no practical difference to things: Kepler was already defending Copernicus in his Mysterium Cosmographicum (1e 1596), and put forward his laws in Astronomia nova (1609), a copy of which he sent to Galileo, which Galileo promptly ignored even two decades later when he published his Dialogue (1632).

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axiologistSep 2023

»Convinced that he had discovered a subtle geometric relationship between the diameters of the planetary orbits and their distances from the Sun, Kepler wrote Mysterium Cosmographicum ('the cosmic mystery'), published in 1596. The scheme worked well with the planetary distances then accepted, but even Kepler could see that it wasn't perfect. Assuming that better data on planetary orbits would bear out his theory, he devoted the rest of his life to justifying his vision through scientific observation and hard mathematical proofs. In pursuing his quest to pin down the cosmic mystery, Kepler transcended formidable obstacles in his personal and professional life and rose to become one of the immortal names in European astronomy.«

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antogniniDec 2020

The article reproduces a famous illustration of Kepler's Platonic solids model of the Solar System from book Mysterium Cosmographicum. There is another beautiful illustration from his later book De Stella Nova that is relevant to the Great Conjunction that occurred just a few days ago:

https://en.wikipedia.org/wiki/Great_conjunction#/media/File:...

This is the so-called "trigon" which was used to predict the location of Great Conjunctions over time. Each conjunction between Jupiter and Saturn occurs every 20 years and about 120 degrees separated in the sky, thereby forming a triangle. But after a cycle the triangle gets rotated by about 8 degrees, so over time you see a slowly rotating triangle. After three or four cycles the locations of the conjunctions shift from one set of constellations to another. These shifts were considered astrologically significant and received a lot of study.

At any rate, this drawing inspired Kepler to try using inscribed polygons to model the distances to the planets. This did not fit the data well so he generalized to three dimensions with Platonic solids and ended up with the model represented by the figure in the article.

It is a shame that it is so difficult to produce good, clear illustrations because, as the article explains, a clear diagram can make a tremendous difference in understanding a difficult concept.

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danharajSep 2017

Reminds me of Kepler's Mysterium Cosmographicum: https://en.wikipedia.org/wiki/Mysterium_Cosmographicum

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