A beautifully told story with colorful characters out of epic tradition, a tight and complex plot, and solid pacing. -- Booklist, starred review of On the Razor's Edge

Great writing, vivid scenarios, and thoughtful commentary ... the stories will linger after the last page is turned. -- Publisher's Weekly, on Captive Dreams

Saturday, October 5, 2013

9. The Great Ptolemaic Smackdown: From Plausible to Proven

Previously: Part 8, Trial and Error

From Plausible to Proven

The great dishonesty of Galileo’s Dialogue was to present a contest between the Copernican and Ptolemaic models.  By that time, both had been smacked down and the real contest was between the Tychonic/Ursine models and Kepler’s model, with the Ursine model being “ahead on points.”  Galileo did not mention either one. He regarded the Tychonic/Ursine models as unaesthetic and klunky.  He seems to have regarded Kepler's model, which came annexed to a physics in which the Sun put out a mysterious force that chivvied the planets about, as occultism.  Besides, he was committed to perfect Platonic circles, and Kepler had ellipticated them.  Boo. 

Galileo’s book “proved popular amongst literati who were not astronomers [and] who enjoyed his very obvious polemic writing skills; but contrary to popular opinion it didn’t play a significant role in the contemporary scientific discussion.”  (Christie, Galileo’s great bluff 2010)  One could even make an argument that Galileo managed to delay acceptance, although TOF does not do so.

What it came down to is that the issue would not be settled by astronomical mathematics, but by a new physics.

Please Help Me, I'm Falling....

The objections to geomobility on the part of the physicists were manifold, but because the old physics is gone, Patient Reader will blink in astonishment at some of the objections and a little thought-balloon reading WTF? will form over his or her noggin.  For example, heavy bodies will in the common course of nature fall toward the center of the world.  If the Sun were in the center of the world, cannon balls dropped from the tower of Pisa would fly off toward the Sun; but we see that they do not, therefore etc.  Us Moderns in our wisdom are left scratching our collective heads and saying Really?

Other objections made more sense, in that we can understand why people would have raised them.
Those headwinds sure are strong!
  • If the world is turning at a high rate toward the east, why is there no steady breeze coming from the east?  This is a sort of ancient Michelson-Morley experiment.  
  • If the earth is whipping around the sun, why isn't the Moon left behind?  (Or the oceans and the atmosphere?)  

Of course, there were answers to these, even then.  "Common motion" asserts that the air shares the earth's rotation, and therefore there would be no particular east wind.  And the moons of Jupiter showed that, whether we knew why or not, moons are not left behind as their planet moves. 

As the earth revolves, the relative positions of the stars
should change
  • If the earth were whipping around the sun, we should see parallax among the fixed stars, but do not.  The Copernicans answered, "Well, yeah, but maybe the stars aren't just far away but really really far away."  But you cannot save an unproven hypothesis by asserting a second unproven hypothesis.  The stars had to be relatively close because otherwise their observed diameters would mean they were ginormous entities. Some Copernicans embraced this and said "Goddidit!"  Who cared how enormous the stars were, since God was infinite.  
As the earth turns a ball at the top of the
tower has a greater eastward velocity
and will fall east of the plumb line
  • If the earth were rotating, objects at the top of a tower would have a greater eastward motion than those at the bottom of the tower; and therefore, a dropped object would not only fall but move eastward realtive to the tower.  No such deflection is observed.  "Well, yeah," said the Copernicans, "it's probably a really small deflection that falls within the error of measurement." 
Maybe so, but science is supposed to be more rigorous than a dorm bull session.  It's not enough to concoct a plausible story.  Sooner or later, there has to be empirical evidence that the story is true.  And this evidence cannot be the same evidence that was used to concoct the story in the first place!

The problem of history, John Lukacs used to tell us is that we "must consider the battle of Salamis as if the Persians might still win."  Meaning that you want to understand what happens in 1633, you can't consider things learned in 1687 or 1803.  The mid-17th century had no clear concept of inertia, of gravitation, of forces, etc.; and while ontologically there may still be no clear concept of these (and therefore we are blind to the foolishness over which our descendents will one day mock us) the same is certainly true of 380 years ago.  After all, the classical, medieval, and Renaissance folks laughed at the ancient belief that the world was flat.  (The Chinese at this point still did believe.)  But because Aristotle had demonstrated that the world was a sphere, the Scriptural passages describing the sky as a tent pitched over a flat earth were no longer understood as literal. 

What was needed now was a new theory of motion.

Just Dropped in to See What Condition My Condition was in

A new theory of motion was already in development.  Aristotle had declared that heavier bodies would fall faster than lighter bodies.  But Albrecht of Saxony described a thought experiment in the 14th century in which he imagined two equal-sized falling bodies attached by a string, and then mentally cutting the string.  It was absurd to imagine the two separate bodies would suddenly decelerate to half speed.  Thomas Bradwardine and the Merton Calculators proved the Mean Speed Theorem and described the free fall of bodies.  Doubts about Aristotle's physics began to circulate.  
1543  Benedetto Varchi publishes a book listing experimental evidence from Francesco Beato and Luca Ghini contradicting Aristotle's view of free fall.

1544  Domingo de Soto, a Dominican philosopher, publishes a book with the first correct statement of the law of free fall.

1570  In Opus novum de proportionibus, Girolamo Cardano, demonstrates that two balls of different sizes will fall from a great height at the same time.

1574 Girolamo Borro, one of Galileo's teachers, describes experiments repeated several times where a wooden and lead ball were thrown out of a high window and the wooden ball reached the ground first.

1575  Guiseppe Moletti, Galileo's predecessor at University of Padua, drops balls of the same volume but different materials and of the same material but different weights and discovers they hit ground at same time.

1585  Flemish Scientist Simon Stevin conducts an experiment dropping two balls, one weighing 10 times the other from 30 feet and discovers that they reach ground at same time.
Aristotelian physics was tottering well before Galileo took up a sledge hammer.

1632.  Bonaventura Cavalieri publishes Specchio Ustoria (On Burning Mirrors).  Otherwise a book about mirrors, it's the first book to describe the parabolic nature of projectile motion. Both Thomas Harriot and Galileo Galilei had described this motion before Cavalieri, but in private notes never published.  Well, Harriot never published nothing, but Galileo was not one for staying mum.  Projectile motion does not sound very heliocentric, but folks are creeping up on a calculus of motion.  For all practical purposes, up to now mathematics basically consists of arithmetic and geometry, with geometry having pride of place.  No wonder Aristotle thought mathematics was unsuited to physics, which involved changeable matter.

Meanwhile, Back at the Glass...

Late 1632.  Leander Bandtius, Abbot of Dunisburgh, (and owner of a particularly fine telescope)  notes a large red spot on Jupiter. 

1636.   In Harmonie Universelle, Fr. Marin Mersenne diagrams the construction of reflecting telescopes in configurations similar to the Gregorian and Cassegrain telescopes.  Parabolic mirrors are notoriously difficult to grind.  Can we say "Hubble Space Telescope"? 

1637.   Galileo Galilei publishes Dialogues Concerning Two New Sciences.  The two sciences are strength of materials, in which he describes the square-cube law, and the physics of motion, in which he confirms De Soto's law and Bradwardine's medieval observations.  He even uses Nicole d'Oresme's graphical geometric proof of the Mean Speed Theorem.  Without attribution, of course.  (The Wikipedia article contains several infelicities.)

Technically, Galileo had been forbidden to publish any new works; but he started writing this while under house arrest in the palace of Archbishop Piccolomini and had arranged for Elsevier to print it in the Netherlands.  The same three characters carry on the dialogue here as in his previous work, but curiously, Simplicio is no longer presented as a stubborn and foolish dork.  (TOF wonders if this was a sort of peace offering to He Who Must Not Be Compared to a Simpleton.)  No one came after Galileo for publishing a new work, so this may simply be an example of the old Renaissance game of official severity coupled with practical leniency.

Jerry Horrocks spots Venus; forgets to tell
anyone else.
4 Dec 1639*.  Jeremiah Horrocks makes the first recorded observation of a transit of Venus from his home near Preston, England.  Horrocks has corrected Kepler's calculations for Venus' orbit and realizes that transits of Venus occur in pairs 8 years apart.  Kepler had predicted a near miss transits for 1639 but Horrocks correction predicts a full-fledged, no-foolin', straight-up Venusian transit.  He has it pegged for 3:00 pm, more or less, the more-or-less part being tricky.  Also, the day is cloudy.  But, shazaam!  The clouds clear at 3:15 pm.  He calculates the size of Venus from the dot in his projected image and from it estimates the Astronomical Unit (mean distance between the Earth and the Sun). He's wrong of course, but he is less wrong than anyone previously.  Then -- wait for it -- true to the great tradition of Harriot, his results will not be published until 1661, after his death.  What is it with those English?
(*) 24 November under the Julian calendar then in use in England.
Francesco Maria Grimaldi.jpg
1640.  Jesuits Francesco Maria Grimaldi and Giovanni Battista Riccioli drop weights from the Torre di Asinelli in Bologna and times the fall using a pendulum. From this he calculates the acceleration due to gravity (g) as 9.144 m/s².  (The modern value is 9.80665 m/s².  Both men have craters named for them on the Moon for the excellent reason that they were the ones who named the lunar craters.

View straight down from the Torre di Asinelli
12 Mar 1641.  In a letter dated, March 13, 1641, Vincenzo Renieri, a professor at the University of Pisa, reports to Galileo on experiments he conducted the day before in which he dropped balls from the Tower of Pisa.  Renieri is an Olivetan monk, an order co-founded by one of the Piccolominis of Siena, and it was at Archbishop Piccolomini's palace that Renieri met Galileo (1633).  When Galileo dies next year, he will leave all his unfinished scientific work for Renieri to complete; but Renieri himself will die shortly after (1647).  Galileo's friend and biographer, Vincenzo Viviani, also a friend of Renieri, will ascribe the Tower of Pisa experiment to his master, starting a legend that lives to this day.

8 Jan 1642.  Galileo goes off to that great observatory in the sky.  Urban's animus pursues him, and will not permit the Archbishop of Florence to bury him in the cathedral as proposed.  Geez, can't he let bygonesbe bygones?

29 July 1644.  Urban VIII finishes his bucket list and kicks off.  Everything is much quieter now. 

I got an idea!  Let's replace wars of dynasties with
wars of nationalism!  Then things will be peaceful!
15 May 1648.  The Peace of Münster is signed, finally ending the Spanish-Dutch portion of the Thirty Years War. 
24 Oct 1648.  The Treaties of Münster and Osnabrück are signed, ending the rest of the Thirty Years War: between the Empire and France and the Empire and Sweden, resp.  But during the peace conference...
All those weeks, all those days, all those last futile hours, they had been fighting at Prague, and went on fighting for nine days longer before they, too, had news of the peace.  Then they, too, fired their salvo to the skies, sang their Te Deum and rang their church bells because the war was over. 

Almost all -- one excepts the King of Sweden -- were actuated rather by fear than by lust of conquest or passion of faith.  They wanted peace and they fought for thirty years to be sure of it.  They did not learn then, and have not since, that war breeds only war.
-- C.V. Wedgwood, The Thirty Years War
Tychonic and Copernican systems argue
on the frontispiece to the New Almagest
while Ptolemy lies prostrate crying
"I will rise again!"

1651. Riccioli publishes his masterwork Almagestum novum. In one section, he presents both major theories -- Copernican and Tychonic -- and gives arguments for and against each one: 
  • 49 arguments in favor of Copernicanism, with rebuttals to each, and 
  • 77 arguments against Copernicanism, with rebuttals to each.   
This is the book Galileo was supposed to write, weighing the pros and cons.  Contrary to popular belief, Riccioli did not simply count the number of arguments, since they were of unequal weight; nor did he decide on the Tychonic model for religious reasons.  Rather, he emphasizes the need for sensible [empirical] evidence as the deciding factor. 
“Both sides present good arguments as point and counter-point. Religious arguments play a minor role in the debate; careful, reproducible experiments a major role.  To Riccioli, the anti-Copernican arguments carry the greater weight, on the basis of a few key arguments against which the Copernicans have no good response.  …  Given the available scientific knowledge in 1651, a geo-heliocentric hypothesis clearly had real strength, but Riccioli presents it as merely the “least absurd” available model…” 
(Graney, 126 Arguments Concerning the Motion of the Earth 2011.)
You are here.  Riccioli's lunar map.
Actually, you are not here; but you once were
The “key arguments against which the Copernicans had no good response” are the lack of parallax and Coriolis effects.  Graney states, “Today, a new theory which predicts observable effects that are not observed, while requiring the ad hoc creation of an unprecedented new type of object [gigantic stars], would have limited appeal, even were it mathematically elegant.”  The Tychonic model fit the data better.  It predicted all the same phenomena as the Copernican, plus it explained why there was no visible parallax or Coriolis.

Unlike Galileo's Dialogue, which was a polemic written for the public, and like Scheiner's Rosa Ursina, Riccioli's New Almagest was a dense, scientific and mathematical tome written for scientists.  It remained a standard text into the 18th century.  In it, Riccioli also reports the value of g for gravitational acceleration, gives the geography of the moon*, shows that bodies do not fall at the same rate,** et al. He gave detailed descriptions of the experiments so that anyone who wished could duplicate them.
(*) geography of the moon. The New Almagest has the first detailed lunar map, with the sea and crater names that we still use.  Riccioli named craters for Copernicus and his followers and for Tycho and Ptolemy and their followers, acknowledging in this offhand manner the collegial and cumulative nature of science.  
(**) do not fall at the same rate.  If two heavy objects of differing weight are dropped simultaneously from the same height, the heavier one descends more quickly provided it is of equal or greater density.  If both bodies are of equal weight, the denser one drops more quickly.  Air resistance does matter.
Christiaan Huygens.jpg
Chris Huygens
1655.  Christian Huygens builds the most powerful telescope ever and  spots a bright moon in orbit around Saturn, which he calls “Saturni Luna.” (In 1847 John Herschel will decide to name it Titan. 

1659.  Huygens studies Saturn some more and discovered the true shape of the planet’s rings. Galileo and others with less powerful telescopes had thought the rings were love handles

The 1660s.  Nearly 120 years after heliocentrism had been formally proposed, Kepler’s elliptical model has won the contest.   The astronomical community has accepted the ellipses with nary a murmur and the Third Law with positive glee.  However, the Second Law (the Equal Area law) is rejected as ugly and Kepler’s proof is deficient.  But the Rudolphine Tables are just plain easier to use.  In the Platonic Renaissance, that carries weight.
There is a long-standing tension between Aristotelians and Platonists over the nature of mathematical physics.  The issue is whether something is true simply because the mathematical model is elegant and "works."  To the Platonists, the mathematics can be more real than the physics. We see that today in the reliance on complex computer models, in which the model output is sometimes, amazingly enough, called "data."  So the Keplerian model was accepted because it was so damn elegant it had to be true and if we keep the faith, sooner or later we'll find the data.  But as Einstein once said to Heisenberg, "Theory determines what can be observed." 
A chronology of Chronos. 
1665.  Riccioli publishes Astronomia Reformata (Reformed Astronomy), a condensed and updated version of the New Almagest.   It incorporates Keplerian ellipses into the Tychonic model.  It includes reports on Bandtius' observation of the Great Red Spot, on the Jovian cloud belts disappearing and reappearing, on the appearance of Saturn's rings from time to time. 

1672. Nicolas Mercator develops a correct mathematical derivation of Kepler's Second Law.  (Christie, Galileo’s great bluff 2010)

1687. Newton presents his theory of Universal Gravitation.  It’s hard for the Late Modern to grasp what a stunning achievement this is.  Suddenly, everything makes sense!  He does not use calculus to do this.  The Principia is carefully structured in correct Aristotelian form, with axioms and deductive logic, to ensure that is true scientia.  There is one elegant solution to all the planets, to all the motions!  Kepler's laws can be deduced from the principle.  Finally, a simple, elegant reason why Kepler’s model ought to be true! 

Just one problem; or rather two:
•    There is still no @#^$% parallax. 
•    There is still no *#^%$ Coriolis effect. 

Dang!  But we can’t let inconvenient facts get in the way of a really kool theory. 

Fat lady finally sings! 

By this time everybody supposes that stellar parallax is simply too small to detect, but there is not yet any empirical evidence that the stars lie at the enormous distances required. 

The lack of Coriolis is more troubling.  Even though a rotating Earth had been more easily accepted than a revolving Earth, the rotation is still undetected.  Newton had described an experiment – dropping a musket ball from a tower – and Hooke had carried it out.  But he reported finding no deflection.

Then comes something really unexpected. 

How aiming a telescope is like running in the rain with an umbrella
If the earth is moving, the telescope will move during the
time light from a star travels down the tube.  Thus you have
to tilt the tube a little bit.

1728.  Building on efforts by Flamsteed, Hooke, and others attempting to detect that old bugaboo, parallax, James Bradley detects stellar aberration in γ-Draconis (Phil. Trans. Royal Soc., 1729).

A similar phenomenon appears when you drive through a snow storm.  Even though the snow is falling straight down, it appears to originate at some point forward of your car.  This is because as snow falls, your car is moving toward the snow.  Similarly, as the starlight falls down the telescope tube, the telescope tube is moving with the earth and the light ray will hit the side of the tube instead of the eyepiece unless the telescope is tilted slightly.  

The effect is small, and detectable only with special instruments, but it counts as a proof that the Earth is moving.  

Huzzah!  Sorta.  It may not convince non-specialists, however.  

1734.  Bradley’s paper is translated into Italian

1744.  A "corrected" copy of Galileo's Dialogue is printed in Italy.  Not a word is changed, but the term "if" is inserted in various marginal topic headers.  This would have been all that was necessary had the original recommendation of the extensor been followed in the Galileo trial.

1758.  Copernicanism is removed from the Index.  Stellar aberration seems to have been sufficient.  

Jun-Sep, 1791.  In a series of experiments, Giovanni Guglielmini, a professor of mathematics at the University of Bologna, drops weights from the Torre dei Asinelli in Bologna -- the same tower used earlier by Riccioli and Grimaldi -- and finds an eastward (and southward) deflection.  Concerned with windage, he repeats the experiment down the center of the spiral staircase at the Instituto della Scienze and finds a 4 mm Coriolis deflection over a 29 m drop; thus providing direct empirical evidence of the rotation of the Earth.  These experiments are later confirmed in Germany (using a mine shaft) and in the United States.

1806.  Giuseppi Calandrelli, director of the observatory at the Roman College publishes "Ozzervatione e riflessione sulla paralasse annua dall’alfa della Lira," reporting parallax in α-Lyrae.  This provides a simple direct observation of the revolution of the Earth. 

Zeus: I've got a splitting headache!
Courtier: Uh... Got wimmin on yer mind?
Keplerian heliocentrism had been accepted because it was computationally easier and because it popped out mathematically from Newton’s theory like Athena from the brow of Zeus.  But now, finally, 263 years after Copernicus, the dual motions are established by empirical fact.  Hot diggity. 

1820.  Giuseppe Settele, astronomy professor at the Sapienza (now the University of Rome) incorporates these findings into the second volume of his Elementa di Ottica e di Astronomia, and tells his colleague, Benedetto Olivieri (who is then Commissary of the Holy Office) that this provides the demonstration requested by Bellarmino back in 1616.  Olivieri agrees, and convinces the Office and Pope Pius VII.

12 Aug 1820.  The injunction is lifted in light of the astronomical discoveries made since Galileo's time:
Decree of Approval for the work "Elements of Astronomy" by Giuseppe Settele, in support of the heliocentric system
The Assessor of the Holy Office has referred the request of Giuseppe Settele, Professor of Optics and Astronomy at La Sapienza University, regarding permission to publish his work Elements of Astronomy in which he espouses the common opinion of the astronomers of our time regarding the earth’s daily and yearly motions, to His Holiness through Divine Providence, Pope Pius VII. Previously, His Holiness had referred this request to the Supreme Sacred Congregation and concurrently to the consideration of the Most Eminent and Most Reverend General Cardinal Inquisitor. His Holiness has decreed that no obstacles exist for those who sustain Copernicus’ affirmation regarding the earth’s movement in the manner in which it is affirmed today, even by Catholic authors. He has, moreover, suggested the insertion of several notations into this work, aimed at demonstrating that the above mentioned affirmation [of Copernicus], as it is has come to be understood, does not present any difficulties; difficulties that existed in times past, prior to the subsequent astronomical observations that have now occurred. [Pope Pius VII] has also recommended that the implementation [of these decisions] be given to the Cardinal Secretary of the Supreme Sacred Congregation and Master of the Sacred Apostolic Palace. He is now appointed the task of bringing to an end any concerns and criticisms regarding the printing of this book, and, at the same time, ensuring that in the future, regarding the publication of such works, permission is sought from the Cardinal Vicar whose signature will not be given without the authorization of the Superior of his Order.
Original Latin source: W. Brandmüller and E.J. Greipl, eds., Copernicus, Galileo, and the Church: The End of the Controversy (1820), Acts of the Holy Office (Florence: Leo Olschki, 1992), pp. 300-301.
 The imprimatur was granted in 1820 and the ban on teaching heliocentrism as proven fact was lifted.

That’s a long time to hold out for empirical confirmation.  

Aside: The Crucial Role of Galileo. 

There was none.  Every discovery made by Galileo was made by someone else at pretty much the same time.  Marius discovered the moons of Jupiter one day later.  Scheiner made a detailed study of the sunspots earlier than Galileo.  The phases of Venus were noted by Lembo and others.  And so on.  Even his more valuable work in mechanics duplicated the work of De Soto, Stevins, and others.  Matters would have proceeded differently -- certainly with less fuss and feathers -- and some conclusions may have taken longer, or perhaps shorter times to achieve.  The thing is, science does not depend upon any single individual.  No one is "the father of" any particular theory or practice.  As Newton observed, he stood upon the shoulders of giants -- a sentiment expressed by Bernard of Chartres back in the Early Middle Ages!  Regarding heliocentrism, Galileo's biggest accomplishment was to get some folks so riled up that the conversation was inhibited for a short time in some quarters.

HISTORY MUST BE CURVED, for there is a horizon in the affairs of mankind.  Beyond this horizon, events pass out of historical consciousness and into myth.  Accounts are shortened, complexities sloughed off, analogous figures fused, traditions “abraded into anecdotes.”  Real people become culture heroes: archetypical beings performing iconic deeds.  (Vansina 1985)

In oral societies this horizon lies typically at eighty years; but historical consciousness endures longer in literate societies, and the horizon may fall as far back as three centuries.  Arthur, a late 5th cent. war leader, had become by the time of Charlemagne the subject of an elaborate story cycle.  Three centuries later, troubadours had done the same to Charlemagne himself.  History had slipped over the horizon and become the stuff of legend.
In AD 778, a Basque war party ambushed the Carolingian rear guard (Annales regni francorum).  Forty years later, Einhard, a minister of Charlemagne, mentioned “Roland, prefect of the Breton Marches” among those killed (“Hruodlandus Brittannici limitis praefectus,” Vita karoli magni).  But by 1098, Roland had become a “paladin” and the central character,  the Basques had become Saracens, and a magic horn and tale of treachery had been added (La chanson de Roland).  Compare the parallel fate of a Hopi narrative regarding a Navajo ambush (Vansina, pp. 19-20). 
This suggests that 17th century history has for the bulk of the population already become myth.  Jamestown is reduced to “Pocahontas,” and Massachusetts boils down to “the First Thanksgiving.”  And the story of how heliocentrism replaced geocentrism has become a Genesis Myth, in which a culture-hero performs iconic deeds that affirm the rightness of Our Modern World-view. 

Conclusion: Our ancestors were not fools. 

In three centuries, the long complex story of how the mobile Earth replaced the stationary Earth dipped below the horizon from History into Legend.  Like all good legends, the story of heliocentrism and the culture-hero Galileo is simple and general and geared toward supporting the Rightness of the Modern worldview.  But history is always detailed and particular.

The reasons for the stationary Earth were rooted in empirical experience and successful modeling.  The dual motion of the Earth is not sensibly evident and was difficult to establish on empirical grounds.  Heliocentrism triumphed first of all because Neoplatonic number mysticism had become au courant during the Renaissance, and Platonists equated mathematical elegance with physical evidence.

Resistance to heliocentrism was rooted in the science of the day and religion entered the picture mainly because the Church Fathers had interpreted Scripture in the light of that science.  They weren’t about to change until there was solid evidence that the science (and hence the interpretation) was wrong; not in the middle of no honkin' Reformation they weren’t.  Thomas Huxley said after investigating the affair that “the Church had the better case.” But Pierre Duhem put it differently.  The Copernicans were “right for the wrong reasons.”  The Ptolemaics were “wrong for the right reasons.”

Science doesn’t follow a mythic positivist ideal but the plural scientific methods described by Feyerabend: a mixture of empiricism, flights of fancy, intuition, aesthetics, doggedness, and jealousy.  Scientific theories are underdetermined.  Any finite set of facts can support multiple theories, and for a long time the available facts were equally explained by geostationary or geomobile models.

In the Legend, the conflict was between Science and Religion.  But in the History, the conflict was between two groups of scientists, with churchmen lined up on all sides.  Copernicanism was supported by humanist literati and opposed by Aristotelian physicists; so it was a mixed bag all around. 
Science does not take place in a bubble.  International and domestic politics and individual personalities roil the pot as well.  The mystery is not why Galileo failed to triumph – he didn’t have good evidence, made enemies of his friends, and stepped into a political minefield.  The real mystery is why Kepler, who actually had the correct solution, constantly flew under the radar.  A deviant Lutheran working in a Catholic monarchy, he pushed Copernicanism as strongly as Galileo; but no one hassled him over it.  Too bad he couldn’t write his way out of a paper bag.

TOF doffs

The end.  Thank goodness.  We now return you to your regularly scheduled blog.  


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    Christie, Thony (2013) He didn’t publish and so he perished (historically).
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  26. Osiander, Andreas.  Foreword to Copernicus' Revolutionibus.  unsigned.
  27. Palmieri, Paolo.  Re-examining Galileo’s Theory of Tides.  Arch. Hist. Exact Sci. 53 (1998) 223–375
  28. Peters, Edward. Inquisition University of California Press, 1989
  29. Ptolemy, Claudius. Syntaxis Mathematiké. In The Great Books Series. Chicago: Encyclopedia Britannica/Univ. of Chicago, 1952.
  30. Rowland, Wade. Galileo's Mistake. New York: Arcade Publishing, 2003.
  31. Sant, Joseph (2012). Jesuits and the Early Telescope:Scheiner and Grienberger.
  32. Sant, Joseph (2012). Timeline of the telescope.
  33. Sant, Joseph (2012). Timeline of mechanics.
  34. Sharratt, Michael. (1994)  Galileo: Decisive Innovator 
  35. Shea, William R. & Mariano Artigas. Galileo in Rome. Oxford: Oxford University Press, 2003.
  36. Shea, William R. & Mariano Artigas.  The Galileo Affair.  A short summary of previous, with slides.
  37. TOF (2011).  The Far Seeing Looking Glass Goes to China
  38. Vansina, Jan. Oral Tradition as History. Madison: University of Wisconsin Press, 1985.
  39. Wallace, William A. The Modeling of Nature. Washington, DC: Catholic University of America Press, 1996.
  40. Wedgwood, C.V. (1938, 1995) The Thirty Years War. (Book of the Month Club reprint)
  41. plus sundry Wikipedia biographies and topic pages, to be used with caution.


  1. Damn fine work. But why don't you boil this down to one paragraph so that it can be communicated and understood on the internet? Who will ever bother to learn such a long and complicated story???? ;-)

    In all seriousness, I'd really like to bone up on how to present some of these mathematical demonstrations to students (e.g., exactly how to calculate the size of the stars). Any of these sources show how?

    1. This shows how to calculate the distance and/or true size of an object, given its angular size as seen from earth.
      The ancients did it through Euclidean geometry.

    2. I can see how they got their distance value by triangulation, but to calculate real size they need to observe/measure the angular diameter. The most common modern method I've found involves the assumption that the earth is good for what I want to do.

      Did they use a giant sextant that could actually measure these small min/sec, or did they have something better? That's the part that's got me stumped right now. I guess what I'd really like is to find out each of the methods all these observers used through the decades/generations until we cheated with radar.


    3. Giant sextant. The instruments at Tycho's Uraniborg observatory were quite enormous. There was a link to them somewhere.... ah.

    4. Found this super-attractive link as well; Brahe's own description of the devices.

      It's humbling to think how accurate they were. Terrific geometric thinking. Thanks for putting me onto my latest history-hobby.


  2. One more question: if the issue was *settled* settled in 1820, why such a sensation over Foucault's Pendulum in 1852? Easier for the layman to understand?

    1. Foucault was French and had at the time abandoned Roman Catholicism, while Guglielmini was an Italian priest. French civil society was in that era intensely anti-clerical. In fact, fifty years after Foucault, such elements would ensure that Pierre Duhem's seminal work on the history of physics would be barred from publication. (We might say, 'placed on the secular index.') Guglielmini's demonstration of the Earth's rotation was more straightforward IMHO.

      One of Duhem's more ominous statements prior to the censorship is worth noting:

      "Science does not know of spontaneous generation. Not even the most unforeseen discoveries have ever been made in all detail in the mind which generated them."

    2. Wow. Knew that 1) by Foucault's time, heliocentricism was 'settled science'; yet 2) Foucault is famous for 'proving' it. Never suspected French politics had anything to do with it. I suppose the moral is: always suspect French politics has something to do with it. Something like that.

      And, yes, direct observation of the Coriolis effect is much cleaner evidence than Foucault's pendulum (unless you could set one up on the on one of the poles - that would be pretty clean).

  3. Brilliant work, Mr. Flynn! Congratulations! Your series will permanently be uploaded onto my Internet Bookmarks. Now, I do have a question: If we wanted a hard copy of this history, which book would you recommend out of your Bibliography? Which did you find most helpful and accessible?

    As an upcoming secondary education history teacher, I want to thank you for this.

  4. If I knew the Irish for "That's just freakin' awesome!" I'd post that...Only, you know, make it sound more classy. Thank you for all the extra reading on our behalf!!

  5. Is there one post that has links to the whole series? or can this post have a "previously on" link so someone can follow the chain to the top?

  6. You have my thanks for this thorough and nuanced treatment of events that are too frequently glossed over.

  7. "In the Legend, the conflict was between Science and Religion. But in the History, the conflict was between two groups of scientists, with churchmen lined up on all sides"

    And then there was Galileo persecuted by the Catholic Church. Let me know when the church corrects this, and then we can start accepting that the the conflict was really just between political powers that may have been incidentally religious.
    "If the earth were rotating, objects at the top of a tower would have a greater eastward motion than those at the bottom of the tower; and therefore, a dropped object would not only fall but move eastward realtive to the tower. No such deflection is observed.

    "Well, yeah," said the Copernicans, "it's probably a really small deflection that falls within the error of measurement."
    Maybe so, but science is supposed to be more rigorous than a dorm bull session.

    Like how much more rigorous would one expect to discount the movement of the Earth in that time period given "no such deflection is observed"?

    What was the value of g measure then, and now?

    1. "And then there was Galileo persecuted by the Catholic Church. Let me know when the church corrects this, and then we can start accepting that the the conflict was really just between political powers that may have been incidentally religious."

      Did you even read this series?

  8. Fantastic and 95% over my head but interesting reading nonetheless! More please! Could you do a series on the evoluation of Evolution?

  9. Really excellent series; perhaps this series will delay the conversion to legend by a few years.

    You referenced de Santillana and some of your conclusions seem to echo what he wrote in Hamlet's Mill. (The ancient engineers weren't fools). Have you written anything about Hamlet's Mill?

  10. This is an outstanding essay, superbly documented and with just the right leavening of wit.

    To the extent that the Church's position on science and the Bible can be gleaned from your exposition of the Copernicus-Kepler-Galileo story, I glean it as follows:

    A scientific theory which does not contradict the language of Scripture may be taught as fact.

    A scientific theory which does contradict the language of Scripture may be taught as fact only after every possible objection to that theory has been conclusively refuted.

    Would you agree, and if not, why not??

    1. A theory cannot be taught as a fact, ever, for the excellent reason that it is not in fact a fact. A theory is a story we tell that helps us "make sense" of a body of facts. It may be well-supported but, as Hume, Popper, and others have pointed out, it can never be known absolutely as true.

      The geo- and helio-centric theories were actually mathematical models. They either predicted or failed to predict accurately. They could be regarded as factual in the sense that the stars and planets really were arranged as the model claimed. That is, they were 'theories' only in the sense that they suppositions about matters of fact. This would be like a 'theory' that there is life on a planet around Tau Ceti. This is not like the theory of electromagnetism or the theory of relativity.

      Such hypotheses can be taught as fact only if they are established as fact. But if the hypothesis leads to the conclusion that there must be stellar parallax and Coriolis effects, then so long as no such consequences can be observed it remains only an hypothesis, no matter how appealing, mathematically amenable, or compatible with a new Zeitgeist it may be.

  11. Impressive... a detailed and whimsical rehash of the Galileo affair, historically accurate, with nary an error....Well done - until you dealt with science in chapter 9. Ah, just one chapter too far.... one step over the line, me boys, just one step over the line.
    Was stellar aberration really the fat lady's swan song? Then why were the critical science details left missing, but not the historical details in the 8 chaps prior?

    1-Aberration is the APPARENT deflection of a light path due to an observer's motion.... as the snowfall-car metaphor supports. But this is a real snow job - the monocausal fallacy. The flakes could be deflected by the wind(aether flow) while the car(Earth)was at rest!.. with the same aberration result. The annual North-South ebb and flow of the cosmic aether that produces starlight aberration is evident to us all in the seasonal N-S migration of the Sun, the solar system, the whole MW....

    2- Parallax?? Shmarallax! Parallax is the APPARENT relative motion of 2 objects relative to a fixed fiducial object. In HC the Sun is assumed to be fixed then, mirabile dictu, it then is proven to be fixed - a classical circular fallacy. For if one instead chooses the Earth as the fixed reference object as in GC, then the Earth is proven fixed! Parallax can compute geometrical relations, but not establish absolute motion.

    3- Free fall deflection in mm. is measured in fact to be eastward and often also southward. Mainstreamers claim the eastward deviation from vertical is due to the Earth's spin; they have no corresponding myth for the southern deflection.
    As it spins around the Earth every sidereal day, the stellar aether produces the eastbound result, the same daily aether vortex that also causes all the stars and galaxies to rotate. As the N-S aether oscillates yearly between +/- 23 degrees of the equator, it creates the average southbound deflection, which varies by day of year and time of day. Aetherodynamics embraces both east and south deviations.
    btw1: Is any logic permitted here? If the Earth were really proven to ALWAYS be in motion, then relativity would be disproven! Oopsie.
    btw2: The daily sidereal aether vortex accounts for the results of other tests: Foucault Pendulum... Michelson-Gale...the greater speed of westbound EM signals over eastbound...
    btw3: The best Galileo ref.? see

    Stick to your talent for embellished historical research - that would be sensible - and leave science and logic to the remnants of the trad Church.

  12. Mike - is there any chance of getting an electronic copy of the whole thing?


    1. I just returned here again and have saved all nine articles to Evernote, just in case this site goes away. Any chance of getting one big PDF or similar?

  13. You are forgetting sth.

    Why "stellar aberration" is not proof. Same reason as why parallax as observed is no proof, nearly. If stars are not immobile and glued to the primum mobile, but have some leeway of proper motion (proper motions given as unidirectional movements to up to 10 arcseconds per year would seem to confirm this), if angels are not just metaphysically able to move celestial bodies if allowed to do so, but regularly given the task of moving them, as both St Thomas and Riccioli thought, how do you know "stellar aberration" and "stellar parallax" aren't simply dance steps that angels take with the celestial bodies that they move?

    I said that Riccioli and St Thomas thought angels move celestial bodies, you have already stated yourself that Galileo took Kepler's theory on celestial motions as a kind of occultism, one can add that his parallel Newton was a practising occultist ...

    You did know Isaac Newton, on top of being a secretive Arian, was also an alchemist, astrologer and generally magician, right?

    ... but I did not give you Riccioli's full list of namedropping in favour of angelic movers.

    Nor the very curious turnabout by 1891, Paris.

    Here I link to Riccioli:

    What Opinion did Riccioli call the Fourth and Most Common One?

    Here I link to a very revised Cornelius a Lapide, edition of 1891, on work of day four:

    What did Cornelius a Lapide REALLY write about Work of the Fourth Day?


  14. Many thanks for filling some of the gaps for me with your witty account. One small thing, it's Newton's Law of Gravity. He wrote that he "brooked no hypothesis" regarding the cause of (explanation for) gravity.

  15. "The religious are the firsts that not belief in God, thus the Inquisition, thus they abuse of the innocents, thus they mislead to the foolish and thus they buy to the folks (Galileo Galilei)"... IT´S TRUTH THAT RELIGION IS LIE

    1. Your meaning is unclear. I take it that English is not your milk language. But the comment seems to have little to do with astronomical mathematics.

    2. unclear are the religious shameless and their buyed "defenders". Is not "unclear" say the truth. People already go to schools and everybody know that religion is a lie. Out religion from the humankind´s future. That is all "friend"

    3. Your grammar makes it difficult to read, but it certainly seems off-topic.

  16. Dear TheOFloinn:

    I am currently teaching "Physics and Astronomy for the Pedestrians" in the University of the Philippines, obviously in the Philippines. In this regard, I have always assigned as a reading material for this great account of yours.

    I would wish that this material be made available to a greater public to put balance into the whole matter especially in the "Galileo Affair". I've seen in your introduction that a State University has been granted privilege to print the whole series for free. Can we do the same as reading material for our teachers in the Philippines?

    Hoping of your approval on this matter. Thank you very much.

    Best regards,


    1. Yes, provided you give full credit and it is not used 'for profit'.

    2. This is great. When we say "full credit" how is this done? :-) I believe it will be used by the Government so, I'll ask them to contact you should it need be. Thank you in advance!

    3. I think:

      Flynn, Michael. "The Great Ptolemaic Smackdown" Parts 1-9. (The TOF Spot, Aug 24, 2013, et al.) <> accessed <> (c)2013, used by permission.

  17. there are very much people like this blog, defending religious miserables. Say this blog: "the great dishonesty of Galileo was...", always the same eh?, people bribed by religious criminals defending pontifices, priest, religious...people bribed for a bowl of lentish. But this is "out" topic. The main topic is: religion and its bribed defenders unclears: out from the Humankind´s Future

    1. It's unclear what you are trying to say. Your comment reads like it was machine generated.

  18. What a great post. I’m really like it! Very, very dgdeeac good!

    flat earth map

  19. There's a lot of snark aimed at Galileo in this series. It's clear you don't like him personally, and I wonder why. It just comes off as a vendetta piece.

    You make two very fundamental errors about the way in which scientific theories are evaluated. Firstly, you argue throughout your series that if a theory makes a prediction (i.e., stellar parallax), that that prediction must be observed. The error in this thinking is that the theory may not predict how large the effect will be. If the theory does not require the effect to be large, the absence of an observed effect is no problem at all. Secondly, you downplay the importance of elegance in a theory. By that, I don't only mean, "I subjectively like this theory." I mean that the theory manages to capture a whole range of phenomena with a smaller set of ad-hoc assumptions. This is an advantage that heliocentric models had over both geocentric and geo-heliocentric models. Perhaps most importantly, the simplest heliocentric model, with circular orbits and no epicycles, already explains retrograde motion - something not even the Tychonic system does (for the outer planets). These types of elegance arguments are very important to scientists (and at a basic level, all scientific thinking is grounded in the idea of parsimony of assumptions).

    Your conclusion about Galileo, that he had no "crucial role," is rather silly. That could be said about any great physicist, including Newton and Einstein. Every major discovery made by either of them would have been made by someone else, had they not existed, and they had contemporaries who were working along similar lines. Galileo, Newton and Einstein are generally counted among the greatest scientific minds in history not just because they were first in one or another publication, but because of the great breadth of their work. It's a truism that scientific progress doesn't depend on one person, but that doesn't mean that the individual scientists do not make outsize contributions to science.

    1. The intriguing thing is that at the time, the scientists did not accept the geomobile theory. The humanists did, and this was largely because it elevated the status of the earth from the bottom of the world to the third heaven. The physicists still wanted some empirical proof that the mathematical model was physically true. Even the mathematicians (astronomers) were hesitant. It's important to remember that Neopythagorean thinking was not entirely ascendant and few were yet in thrall to the notion that a model must be true simply because it was mathematically elegant. Things that scientists accept today with an "of course" were brand new back then. Heck, even Hawking has made the remark that the existence of a term in a mathematical model does not obligate the physical world to go along with the gag.

      A simple "heliocentric" model without epicycles explained nothing, because there wasn't one. Without Copernicus' twenty or so epicycles, the geomobile model would have been so badly off on the positions of the planets as to be useless.

      The Copernicans did respond to the lack of parallax with the plea that the parallax might be much smaller because the stars were much farther away than believed; but this is trying to save one unproven hypothesis with the introduction of another, unproven hypothesis. Physics demands physical demonstration, not plausible argumentation. They said, fine. Show us the parallax or show us some reason why it must be so. (Recall that the distance to the stars had been measured by their apparent brightness and diameters. No one would know until George Airy that those "diameters" were illusions caused by aberration. Until then, stars like Procyon could not be too much farther off than Saturn without being incredibly large -- larger, in fact, than the entire solar system -- and they were reluctant to multiply entities without cause.

      The problem was that none of Galileo's observations demonstrated empirically that the Earth possessed a dual motion, nor any motion of all. Nor did Copernicus' mathematics demonstrate a reason to overthrow all of physics. Geomobility required not just new star tables, but new physical theories such as "inertia," "mass," etc.

      Galileo was not a physicist. He was a mathematician, a lower rung on the academic ladder. (Imagine if a computer programmer today promoted a new physics theory that would require overthrow of the Standard Model.) Nor did he even devise any new mathematics. Unlike Kepler, he simply pumped for Copernicus' model.

      If geomobile theories more elegantly explained retrograde motion than did epicycles, they failed utterly to explain the apparent lack of parallax and Coriolis effects. The Tychonic and Ursine models explained the apparent lack of motion without the need for ad hoc hypotheses about distances and sizes. So as to which was more elegant, it was a toss-up. The Prussian Tables (Copernicus) and the Tychonic tables made all the same predictions. And the Tychonic predictions were better -- because Copernicus had worked with old corrupted data from the Alphonsine Tables, while Tycho had made fresh, calibrated observations. This required Galileo to mock Tycho in the fine old Renaissance style. Neither system made a good account of Mars (whose orbit is highly elliptical). That's why Kepler and his elliptical orbits deserves the oxygen that Galileo sucked out of the room, at least so far as astronomical models go.

      In sum, hindsight is always 20/20, but it was not evident at the time which model was more true nor even why one model ought to be more true. That was the contribution of Newton's theory of universal gravitation: it gave a theoretical reason why Kepler's model should be true even in advance of empirical evidence.


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