Category Archives: History of Astronomy

Looking up to Marius

One of the principle principal goals of the Simon-Marius-Anniversary-2014 has been achieved. The committee of the International Astronomical Union (IAU) responsible for the naming of minor planets, comets and natural satellites has announced that the asteroid “1980 SM” will in future be known as “(7984) Marius”. The minor planet in the so-called main belt between Mars and Jupiter was first observed at the Klet’ Observatory (Hvězdárna Kleť) on 29th September 1980.

The Minor Planet Center (MPC) announced the decision of the Committee for Small-Body Nomenclature of the International Astronomical Union (IAU) at the end of March, whereby the asteroid discovered by the Czech astronomer Zdeňka Vávrová will be named after the Ansbach Court Astronomer, Simon Marius (1573–1624). The heavenly body has an orbit of 4.27 years and is 2.63 AU distance from the sun. Its average speed is 7.57 km/s.

Marius-Solar-System Norman Schmidt

Norman Schmidt

The recognition by the International Astronomical Union is a great honour for the Franconian astronomer whose magnum opus “Mundus Jovialis” was published four hundred years ago. In this work he describes the discovery of the four largest Jupiter moons, which Galileo Galilei and Simon Marius observed for the first time in January 1610. Galileo, having published first, accused Marius of plagiarism, a charge that was only shown to be unfounded at the beginning of the twentieth-century.

Various events within the framework of the Simon-Marius-Anniversary 2014 recognise his achievements and the Nürnberger Astronomische Gesellschaft has setup the 24-Language Marius-Portal, which brings together all the electronic sources as well as the secondary literature to make them available to the international research community and all other interested parties. The naming of the asteroid is the second milestone.

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Filed under History of Astronomy

Did Edmond tells Robert to, “sling his hooke!”?

The circumstances surrounding the genesis and publication of Newton’s magnum opus, Philosophiæ Naturalis Principia Mathematica, and the priority dispute concerning the origins of the concept of universal gravity are amongst the best documented in the history of science. Two of the main protagonists wrote down their version of the story in a series of letters that they exchanged, as the whole nasty affair was taking place. Their explanations are of necessity biased and unfortunately we don’t have equivalent written evidence from the third protagonist Robert Hooke, although we do have the earlier exchange of letters between Hooke and Newton that led Hooke to making his claims to being the author of the idea. All of this is documented, analysed and discussed in detail by Richard S. Westfall in his authoritative biography of Newton, Never at Rest. Lisa Jardine sketches the whole sorry episode in the introduction to her Hooke biography The Curious Life of Robert Hooke: The Man Who Measured London. Beyond this there is a whole raft full of academic papers and monographs on Hooke, Newton, Halley, Principia and the Royal Society that discus the whole or various aspects of the story. Any first year history of science student should be able to write an accurate and informed essay or term paper on this important moment in the history of seventeenth-century scientific publishing. In fact it would make a very useful exercise for such students. The scriptwriters of Cosmos would however get a fat F for their efforts to present the story. Maybe they should have turned to one of those first year students for help?

Thanks to the services of a beautiful fairy princess I was finally able to watch the third episode of the much hyped American television series Cosmos and, as predicted by numerous commentators on Twitter, I was more than underwhelmed by the animation telling the story of the publication of Principia Mathematica and its significance in the history of science.

Our tale starts with an introductions to the hero of the day, Edmond Halley, an interesting choice of which I actually approve but the first error come up with the tale of the young Halley’s journey to St Helena to map the southern skies. We get told that this is the first such map. This is simply not true Dutch seamen had already started mapping the southern hemisphere at the end of the sixteenth-century. Halley’s government sponsored voyage was the English attempt to catch up. Having established Halley as a scientific hero we get presented with Robert Hooke who is to play the villain of the piece.

At the beginning we get a very positive portrait of Hooke outlining the very wide range of his scientific activities. Unfortunately this presentation is spoilt by a series of bad history of science blunders. Introducing Hooke’s microscopic investigations we get told that Hooke invented the compound microscope. Given that compound microscopes were in use twenty years before Hooke was born, I hardly think so. We then get told that Hooke improved the telescope. Whilst it is true that Hooke proposed several schemes to improve the telescope, some of them positively Heath-Robinson, none of them really proved practical and there are no real improvements to the telescope that can be laid at Hooke’s door. Next up we are informed that Hooke perfected the air pump. Hooke did indeed construct the air pump that he and Robert Boyle used for their experiments, their model was in fact ‘perfected’, although improved would be a better term as it was anything but perfect, by Denis Papin.

Moving on, we are introduced to the London coffee houses, without doubt centres of scientific communication in the late seventeenth- and early eighteenth-centuries. However Tyson claims them to be laboratories of democracy. Sorry but all I can say to this piece of hogwash is bullshit. We come to the coffee house because of a legendary conversation between Halley, Hooke and Christopher Wren that took place in one of them in January 1684, concerning the law of gravity. This conversation is indisputably a key moment in the history of science and that is the reason why it is featured in this episode of Cosmos. Given this one would expect that the scriptwriters would get the story right, however ones expectations would be dashed. According to Cosmos the three speculated as to whether there was a mathematical law governing celestial motion and then Newton, to whom I will come in a minute, produced the inverse squared law of gravity like a conjuror pulling his rabbit out of his hat. In fact all three participants were aware of speculations concerning an inverse squared law of gravity and Hooke claimed that he could deduce the motions of the heavens from it. Wren doubted this claim and offered a prize for the first to do so. Hooke persisted that he already had the solution but would first reveal it when the others had admitted defeat.

Cosmos has Halley, unable to solve the problem rushing off the Cambridge to ask Newton if he could solve it. In fact Halley being in Cambridge in August of the same year met Newton and in the course of their conversation asked Newton, “what he thought the Curve would be that would be described by the Planets supposing the force of attraction towards the Sun to be reciprocal to the square of their distance from it, Sr Isaac replied immediately that it would be an Ellipsis…”[1] The description of Newton given by Cosmos introducing this fateful meeting also owes more to fantasy than reality. We get told that Newton went to pieces over his dispute with Hooke concerning his theory of light, that he had become a recluse and that he was in hiding in Cambridge. Although Newton declined to have anything more to do with the Royal Society following the numerous disputes, not just with Hooke, following the publication of his theory of light in 1672 he certainly did not go to pieces, giving as good as he got and he was not hiding in Cambridge but working there as Lucasian Professor of Mathematics. Also far from being a recluse he was corresponding with a wide range of other scholars, including Hooke with whom he had sealed an uneasy truce. Blatant misrepresentations might be all right in a historical novel but not in a supposedly serious television documentary claiming to present history of science.

We now move on to the writings that Newton’s meeting with Halley provoked. First we get shown Du motu corporum in gyrum (On the Motion of Bodies in Orbit) a nine page pamphlet demonstrating the truth of Newton’s statement and quite a lot more, although Tyson doesn’t think it necessary to give us either the title or a description of the contents calling it instead, “the opening pages of modern science”, a truly crap statement. If De motu represents the opening pages of modern science what was all the stuff that Kepler, Stevin, Galileo, Pascal, Descartes, Mersenne, Huygens et al. did? Most of it before Newton was even born! There is worse to come.  In the Cosmos version of the story Halley now urges Newton to turn De motu into a book, in reality Halley wanted to enter De motu officially in the Royal Society’s register “to secure his [Newton’s] invention to himself” and it was Newton who insisted on rewriting it. It was this rewritten version that became Principia Mathematica. When almost complete the council of the Royal Society agreed that it should be published by the Society. At this point the proverbial shit hit the fan. As related in Cosmos, Hooke raised a claim to the theory of gravity and demanded that Newton give him credit for it in his book. Newton’s prickly response was to threaten to withhold volume three of the Principia, which is actually the part in which he applies his theories of motion and the law of gravity to the celestial motions i.e. the heart of the whole thing. Tyson now said, “The scientific revolution hung in the balance”! I said worse was to come.

According to convention wisdom the scientific revolution began in 1543 with the publication of Copernicus’ De revolutionibus. I’m a gradualist who doesn’t accept the term scientific revolution and for me the evolution of modern science begins around fourteen hundred although it builds on earlier medieval science. For most historians Newton’s Principia is the culmination not the beginning of the scientific revolution. It was even fashionable for a time to play down Newton’s achievement claiming that he only synthesised the result won by his predecessors. However it is now acknowledged that that synthesis was pretty awesome. However let us play a little bit of what if. If Newton had only published the first two volumes of Principia I doubt that it would have been very long before somebody applied the abstract results derived in volume one to the solar system and completed what Newton had begun. Put another way nothing hung in the balance.

In fact Halley was able to mollify Newton and the letters that the two of them exchanged at this time are the main historical source for the whole story. Cosmos paints Hooke as an unmitigated villain at this point in the story, which is again a distortion of the true facts. Hooke had indeed suggested, in print, a universal theory of gravity based on the inverse squared law and the letters he exchanged with Newton, during the uneasy truce mention above, had played a significant role in pushing Newton towards his own theories of motion and gravity. Hooke’s claim was not totally unfounded. It is true, however, that his claim was exaggerated because he did not possess the mathematical skills to turn those hypotheses into the formal mathematical structure that is the glory that is Newton’s Principia. There was blame on both sides and not just on Hooke’s. Cosmos now introduces a strange scene in which Wren and Halley meet up with Hooke and confront him on the gravity priority issues, Halley even telling Hooke to “put up or shut up”! Numerous people on Twitter commented on this sound bite, most of them betting that Halley never said it. Not only did Halley never say it, the whole scene is a product of the scriptwriter’s fantasy; in reality it never took place. Remember this is supposed to be history of science and not historical fiction.

With then get treated to the infamous History of Fish episode. In 1685 the Society had published Francis Willughby’s De historia piscium, which had been finished and edited posthumously by John Ray. The book having many lavish illustrations was costly and sold badly putting a serious strain on the Society’s, in the seventeenth-century always dodgy, finances leaving no money to fulfil the commitment to publish Newton’s Principia. This is a well-known and oft repeated story and mostly told at the cost of Willughby and his book. Cosmos did not deviate from this unfortunate pattern telling the story in a heavy handed mocking style. For the record Willughby’s book is an important publication in the history of natural history and deserves better than the treatment it got here.

Before we leave Newton and his masterwork we get presented with yet another historical clangour of mindboggling dimensions. Tyson informs us in his authoritative manner that Principia also contains Newton’s invention of the calculus. Given the amount of printer’s ink that had been used up in the academic discussion as to why Newton wrote the Principia in Euclidian geometry and not calculus this is an unforgivable gaff. I repeat for those who have not been paying attention there is no calculus in Newton’s Principia.

We now leave Newton and turn our attention to his sidekick Edmond Halley. We get a brief presentation of some of the non-astronomical aspects of the good Edmond’s life, which also contain several minor historical errors that I can’t be bothered to deal with here, before turning to the central theme of the programme, comets. There is however one major astronomical subject that I cannot ignore, the Transit of Venus. It was not, as claimed, Halley who first proposed using the Transit of Venus to determine the astronomical unit, the distance of the sun from the earth, but James Gregory in his Optica Promota published in 1663. We then get presented with the rather strange spectacle of James Cook sailing off to Tahiti in 1769 to observe the Transit. This is strange not because it’s wrong, it isn’t, Cook did indeed observe the Transit on Tahiti in 1769 but because the programme created the impression that he was the first and only person to do so. In reality Cook’s expedition was only one of many international expeditions that took place in 1769 for this purpose also there had been almost as many expeditions that had set out for the same purpose in 1761. We do not owe our knowledge of the size of the astronomical unit to some sort of solo heroic efforts of Cook in 1769 as implied by Cosmos.

The opening section of the episode was actually very well scripted with a sympathetic and understanding explanation as to how humanity came to view comets as harbingers of doom. Unfortunately this good beginning was ruined by the claim that was repeated several times throughout the script that it was Newton and Halley who were the first to view comets as astronomical objects and thus free humanity from its superstitious fear. This is just plain wrong.

In the Early Modern Period Paolo dal Pozzo Toscannelli was the first to make astronomical observations, as opposed to superstitious wonderings, of two comets in 1433 and 1456. He did not publish those observations but he did befriend Georg Peuerbach on his study journey through Renaissance Italy. Peuerbach and his pupil Regiomontanus made similar observations in Vienna in the middle of the fifteenth-century and Regiomontanus wrote an important text on the mathematical problem of measuring the parallax of a moving comet, which wasn’t published in his own lifetime.

In the 1530s several European astronomers carried out astronomical observations of a series of spectacular comets. This period led to Johannes Schöner publishing Regiomontanus’ comet text. Peter Apian published a pamphlet on his observations describing, what is incorrectly known as Apian’s Law because it was already long known to the Chinese, that the comet’s tail always points away from the sun. This series of comets and the observations of them led to an intense scientific discussion amongst European astronomers as to the physical nature of comets and their position in the heavens, above or below the moon, sub- or supra-lunar? Fracastoro, Frisius, Cardano, Jean Pena and Copernicus took part in this discussion.

In 1577 astronomers throughout Europe again observed a spectacular comet to test the theories proposed by those who had taken part in the 1530s discussions. Famously Tycho Brahe and Michael Maestlin, amongst others, determined that this comet was definitely supra-lunar. In the same period Brahe and John Dee corresponded on the subject of Regiomontanus’ comet text, the determination of cometary parallax.

Cometary observation again hit a high point in astronomical circles in 1618. The comets of this year famously led to the dispute between Galileo and the Jesuit astronomer Orazio Grassi that culminated in Galileo’s Il Saggiatore, one of the most often quoted scientific publications of all times. They also saw the publication of a much more low-key text, Kepler’s book on comets published in 1619. Kepler summarised in his work all of the astronomical knowledge on comets that had been gained in the Early Modern Period, concluding himself that comets are supralunar and travel in straight lines. Ironical someone else had suggested that comets follow Keplerian elliptical orbits eight years earlier. Thomas Harriot and his pupil William Lower had observed the comet of 1607, Halley’s comet, and were amongst the first to read Kepler’s Astronomia nova when it appeared in 1609 and to become convinced Keplerians. In a letter to Harriot, Lower suggested that comets, like the planets, have elliptical orbits. Lower’s suggestion did not become generally known until the nineteenth century but it shows that the discussion on the flight path of comets was already in full swing at the beginning of the seventeenth-century.

With the comets of the 1660’s the debate on the nature of comets and their flight paths again broke out amongst the astronomers of Europe with Kepler’s comet book at the centre of the debate, so when Newton and Halley entered the fray in the 1680s they were not initiating anything, as claimed by Cosmos, but joining a discussion that had been going on for more than two hundred years. A final omission in the Cosmos account concerns another man with whom both Halley and Newton would become embroiled in bitter disputes, the Astronomer Royal John Flamsteed. The early 1680s saw a series of spectacular comets that Flamsteed observed from Greenwich and Halley from Paris.  Flamsteed concluded that two of these were in fact one and the same comet first observed on its way to the sun and then again on its way away from the sun having passed behind it. He reported this theory to Newton who at first rejected it but then on further consideration accepted and adopted it, making comets a central theme for his research for the Principia, utilising Halley as his assistant for this work. That comets follow flight paths described by the various conic sections depending on their velocities, some of them elliptical, under the influence of the law of gravity is a central element of volume three of Principia and not something first determined by Halley in his 1705 paper as claimed by Cosmos. Halley undertook his research into the historical records of comets to see if he could find a reoccurring comet to confirm the theory already presented in Principia, as everybody knows he was spectacularly successful.

Having completely messed up the history of astronomical cometary observation Cosmos closed by returning to the Newton Hooke dogfight. We get told Hooke died in 1703 as a result of his unhealthy habits of doctoring himself with all sorts of substances. Given that Hooke lived to the age of 67, not at all bad for the seventeenth-century I found this to be an unnecessary slander on the poor man. Tyson then went on to say that Newton replaced him as President of the Royal Society. Robert Hooke was an employee of the Royal Society and never its President. Newton in fact followed Lord Somers in this august position. Although hedged with maybes, we then got the old myth of Newton burning Hooke’s portrait dished up once again. On this hoary old myth I recommend this post by good friend Felicity Henderson (@felicityhen) on her Hooke’s London Blog (always well worth reading). Given the vast amount of real history of science that they could have brought I don’t understand why Cosmos insists on repeating myths that were discredited long ago.

The history of science presented in this episode of Cosmos was shoddy, sloppy, badly researched, factually inaccurate and generally of a disgustingly low level. On Twitter the history of science hashtag is #histsci, historian of biology Adam Shapiro (@TryingBiology) suggested that the hashtag for Cosmos history of science should be #HistSigh, I concur.


[1] Richard S. Westfall, Never at Rest: A Biography of Isaac Newton, Cambridge Paperback Library, Cambridge University Press, 1983, p. 403. Quoting Abraham DeMoirve’ s account of the meeting as related to him by Newton.


Filed under Early Scientific Publishing, History of Astronomy, History of science, Myths of Science, Renaissance Science


The title is supposed to make you think of a typical article in the Daily Fail, Britain’s most obnoxious representative of the gutter press. It represents one of the dominant reactions by members of the Gnu Model ArmyTM to the Cosmos Bruno AffairTM. According to people such as Jason Rosenhouse and P Z Myer the persecution of such notable scientists as Giordano Bruno and Galileo Galilei by the Catholic Church has definitely hindered the progress of science and for good measure they or their supporters quote the words of wisdom of Über-Guru Neil deGasse Tyson that without religion science would be a thousand years more advanced. What an outrage, truly horrific the Church it seems has a lot to answer for, although I find it rather strange that they can’t dish up more examples than poor old Giordano and that universal symbol of Church oppression Galileo. I’m sure if they re-read their Draper-White they could manage to find some new names to beat the ignorant historians around the head with. I say ignorant historians because it was the historians complaining about the Bruno cartoon on the first episode of Cosmos that has brought out this charge by these stalwart defenders of scientific integrity.

Let us assume for a moment that Rosenhouse-Myer are correct and that the Catholic Church did in fact persecute Bruno and Galileo to block scientific progress does this necessarily mean that they were successful in their dastardly deeds? Did they truly manage to interrupt, slow down, or hinder the adoption, acceptance or acknowledgement of the heliocentric hypothesis or the belief in an infinite universe or the perception that the sun is a star or vice versa? No doubt about it, this is a serious charge and one that should definitely be explicated.

Now Myer and Tyson are both practicing scientists whilst Rosenhouse is a mathematician, all of them work in disciplines that require one, if one makes a substantial claim, to provide the appropriate evidence or proof to support that claim. What is with their claim that religion has blocked the advance of science in general or in the case of Bruno and Galileo the acceptance of modern astronomy and cosmology in particular? Have our scientific practitioners provided the necessary evidence to back up their claims? Do they provide a tightly argued historical thesis based on solid documentary evidence to prove their assertions? Can they demonstrate that if the Church had not intervened modern astronomy would have become accepted much earlier than it was? Given their outspoken support of the ‘scientific method’, whatever that might be, you would expect them to do so, wouldn’t you? Do they hell! They don’t waste one single word on the topic. No evidence, no proofs, no academic arguments just plain straightforward unsubstantiated claims in the style of the gutter press. A pretty poor showing for the defenders of scientific faith.

But could they still be right? Even if they don’t take the trouble to provide the historical discourse necessary to substantiate their claims, could it be true that the Church’s actions against Bruno and Galileo did in fact have a negative influence on the acceptance of heliocentricity and other aspects of modern astronomy and cosmology? Let us examine the historical facts and answer the questions that Rosenhouse-Myer and Tyson are apparently above answering, the truth being apparently so obviously clear that they don’t require answering.

To start with the poor Giordano, Bruno was one of those who advocated Copernicus’ heliocentric astronomy already in the sixteenth-century. He however went beyond Copernicus in a series of cosmological speculations and it is these that Cosmos thought to be so important that they devoted eleven minutes of a forty-five minute broadcast to them. I shall deal with the acceptance of heliocentricity separately later and only address Bruno’s cosmology now. Copernicus himself expressly left the question as to whether the cosmos is finite or infinite, as he said, to the philosophers, with good reason. This question was purely speculative and could not, with the evidence and possibilities available to the Renaissance astronomer, be addressed in anything approaching a scientific manner. To all intents and purposes the cosmos appeared finite and Renaissance scholars had no means available to prove otherwise. Bruno’s speculation was of course not new.

In his own times Nicolas Cusanus had already considered the question and earlier, in the first-century BCE, the Epicurean philosopher poet Lucretius, Bruno’s inspiration, had included it in his scientific poem De rerum natura. Lucretius of course did not invent the concept but was merely repeating the beliefs of the fifth-century BCE Greek atomists. All of this demonstrates that the idea of an infinite cosmos was fairly common at the beginning of the seventeenth century and nothing the Church said or did was likely to stop anybody speculating about it. The thing that prevented anybody from going further than speculation was the lack of the necessary scientific apparatus to investigate the question, a similar situation to that of the string-theorists and multiverse advocates of today.

This does not mean that astronomers did not address the problem of the size of the cosmos and the distance to the stars. Amongst others Galileo, Jeremiah Horrocks, Christiaan Huygens and Isaac Newton all tried to estimate/calculate the distances within the solar system and outward towards the stars. First in the middle of the eighteenth century with the transit of Venus measurements were these efforts rewarded with a minimum of success. It wasn’t until the early nineteenth century that the first stellar distance measurements, through stellar parallax, were achieved. All of these delays were not caused by anything the Church had done but by the necessity of first developing the required scientific theories and apparatus.

Bruno’s next cosmological speculation was that the sun and the stars were one and the same. Once again there was nothing new in this. Anaxagoras had already had the same idea in the fifth-century BCE and John Philoponus in the fifth-century CE. Once again the problem with this speculation was not any form of religious objection but a lack of scientific theory and expertise to test it. This first became available in the nineteenth century with development of spectroscopy. This of course first required the development of the new matter theory throughout the seventeenth and eighteenth centuries, a process that involved an awful lot of science.

Bruno’s last speculation and the one that bothered the Church was the existence of inhabited planets other than the Earth. Again this was nothing new and whatever the Church might have thought about it that speculation generated a lively debate in the seventeenth century that is still going on. We still don’t actually know whether we are alone or not.

Given my knowledge of the history of science I can’t see anywhere, where the Church hindered or even slowed down scientific progress on those things that Bruno speculated about in his cosmological fantasy. But what about heliocentricity, here surely the Church’s persecution of both Bruno and Galileo hindered science bay the hounds of anti-religious rationalism.

What follows is a brief sketch of the acceptance of the heliocentric astronomy hypothesis in the sixteenth and seventeenth centuries. This is a subject I’ve dealt with before in various posts but it doesn’t hurt to repeat the process as there are several important lessons to be learnt here. To begin with there is a common myth that acceptance of ‘correct’ new scientific theories is almost instantaneous. To exaggerate slightly, Einstein published his General Theory of Relativity in 1915 and the world changed overnight or at the latest when Eddington confirmed the bending of light rays conform with general relativity in 1919. In reality the acceptance of the general theory of relativity was still a topic of discussion when I was being educated fifty years later and that despite numerous confirmatory tests. Before it is accepted a major new scientific theory must be examined, questioned, tested, reformed, modified and shown to be superior to all serious alternatives. In the Early Modern Period with communication considerably slower this process was even slower.

Copernicus published his De revolutionibus in 1543 and there were only ten people in the entire world, including Bruno but much more importantly both Kepler and Galileo, who accepted it lock, stock and barrel by 1600. This system had only one real scientific advantage over the geocentric one; it could explain the retrograde movement of the planets. However this was not considered to be very important at the time. There were some relatively low-key religious objection but these did not play any significant role in the very slow initial acceptance of the theory. The problematic objections were observationally empirical and had already been discussed by Ptolemaeus in his Syntaxis Mathematiké in the second-century CE. Put very simple if the world is spinning very fast and hurtling through space at an alarming speed why don’t we get blown away? Copernicus had the correct answer to this problem when he suggested that the atmosphere was carried round with the earth in the form of a bubble so to speak. Unfortunately he lacked the physics to explain and justify such a claim. It would take most of the seventeenth century and the combined scientific efforts of Kepler, Galileo, Stevin, Borelli, Descartes, Pascal, Huygens, Newton and a whole boatload of lesser lights to create the necessary physics to explain how gravity holds the atmosphere in place whilst the earth is moving.  This process was not hindered by the Church in anyway whatsoever.

There was a second level of acceptance of Copernicus theory, an instrumental one, as a mathematical model to deliver astronomical data for various applications, astrology, cartography, navigations etc. Here the system based on the same inaccurate data as the Ptolemaic one did not fair particularly well. Disgusted by the inaccuracy of both systems Tycho Brahe started a new long-term observational programme to obtain new accurate data. Whilst doing so he developed a third model, the so-called geo-heliocentric model, in which the planets orbited the sun, which in turn orbited the stationary earth. This model had the advantage of explaining retrograde motion without setting the earth in motions, a win-win situation.

The first major development came with the invention of the telescope in 1608 and its application to astronomical observation from 1609 onwards. The first telescopic discoveries did not provide any proofs for either the Copernican or the Tychonic models but did refute both the Aristotelian homocentric model and the Ptolemaic model. Around the same time a new candidate, the Keplerian elliptical astronomy, entered the ring with the publications of Kepler’s Astronomia nova in 1609. For a full list of the plethora of possible astronomical models at the beginning of the seventeenth century see this earlier post.

By 1620 the leading candidate was a Tychonic model with diurnal rotation. It should be pointed out that due to the attempts of Galileo and Foscarini to reinterpret Holy Scripture in favour of heliocentricity the Catholic Church had entered the action in 1615 and forbidden the heliocentric theory but not the heliocentric hypothesis. The distinction is important. The theory says heliocentricity is a scientific fact the hypothesis says it’s a possibility. At this time heliocentricity was in fact an unproved hypothesis and not a theory. This is the point where Rosenhouse-Myers step in and claim that the Church hindered scientific progress but did they. The straightforward answer is no. The astronomers and physicist carried on looking for answers to the open questions and solutions to the existing problems. There is no evidence whatsoever of a slowing down or interruption in their research efforts.

Between 1618 and 1621 Kepler published his Epitome astronomiae Copernicanae explaining his elliptical astronomy and his three laws of planetary motion in simple terms and in 1627 the Tabulae Rudolphinae the astronomical tables based on his system and Tycho’s new accurate data. It was these two publications that would lead to the general acceptance of heliocentricity by those able to judge by around 1660. Kepler’s publications delivered the desired accurate prognoses of planetary positions, eclipses etc. required by astrologers, cartographers, navigators etc.

At no point in the 120 years between the initial publication of Copernicus’ De revolutionibus and the general acceptance of heliocentricity in the form of Kepler’s elliptical astronomy is there any evidence of the Church having slowed or hindered progress in this historical process. To close it should be pointed out that it would be another seventy years before any solid scientific evidence for the heliocentric hypothesis was found by Bradley, in the form of stellar aberration.






Filed under History of Astronomy, History of science, Myths of Science, Uncategorized

Cartoons and Fables – How Cosmos Got the Story of Bruno Wrong

One of the joys of writing this blog is that I have a number of readers/commentators who are more intelligent, more knowledgeable, more erudite and above all more sensible than I. Every now and then I succeed in trapping, blackmailing, bullying or conning one of them into writing a guest post in order to give you the readers an alternative perspective on the world of the history of science and the chance to read something of quality. This time I have succeeded in acquiring the literary services of Tim O’Neill, historian and inexhaustible warrior against the misuse and abuse of the history of science. In his post Tim adds his tuppence worth to the debate raging far and wide about the Bruno cartoon in the first edition of the Cosmos reboot. Enjoy! 

A few months ago while visiting Rome I did something a tourist should not do in a strange city – I took a short cut.  Walking back from the Forum to my apartment over the Tiber, I should have taken the obvious route down the Corso Vittorio Emanuele II toward the Castel  Saint ‘Angelo, but I decided I knew where I was going, so I took a more direct path through some back streets and soon became completely lost.  After winding my way through a maze of smaller laneways trying to find a major road I saw a piazza up ahead and so decided to use that to get my bearings.  I stopped under a statue in the middle of the square to get out a map, looked up at the statue and immediately knew where I was.  I realised I was in the Campo de’Fiori, because the statue was the famous monument to Giordano Bruno, raised on the spot where he was burned at the stake in February 1600.

Bruno 2013 Photo: Tim O'Neill

Bruno 2013
Photo: Tim O’Neill

Bruno is the poster boy of the Draper-White Thesis – the idea that science and religion have always been at war and an idea beloved by the New Atheist movement despite the fact it was rejected by actual historians of science about a century ago.  Try to engage in an attempt at intelligent discussion of the real and much more complex and nuanced interrelations between religion and what was to emerge as modern science in the medieval and early modern periods and Bruno is usually brandished as “proof” that the Church was the implacable and ignorant foe of early science.  After all, why else did they burn him for daring to say the earth wasn’t the centre of the universe and that the stars were other suns with planets?  For those who prefer simple slogans and caricatures to the hard work of actually analysing and understanding history, Bruno is a simple answer to a intricate question.  Nuance and complexity are the first casualties in a culture war.

So when I saw the first preview clips of the revamped version of Carl Sagan’s Cosmos, this time presented by Sagan’s genial protégé Neil deGrasse Tyson, and noticed an animated sequence of someone being menaced by Inquisitors and burned at the stake, I knew that the revived Cosmos was going to be presenting some bungled history.  This was also following in Sagan’s footsteps, I suppose, since in the original series he veered off into a mangled version of the story of Hypatia of Alexandria that fixed the false idea of her as a martyr for science in the minds of a generation, as I’ve discussed elsewhere.

So when the first instalment of the new series – Cosmos: A Spacetime Odyssey -  went to air last week, at its heart was an eleven minute version of the Bruno myth.  I often refer to the simplistic moral fable that people mistake for the history of the relationship between the Church and early science as “the cartoon version”, because it’s oversimplified, two-dimensional and reduced to a black and while caricature.  But in this case it really is a cartoon version – the sequence was animated, with the voice of Bruno provided by the series’ Executive Producer, Seth MacFarlane, of Family Guy fame, which seems to be why Bruno has an Italian accent of a kind usually heard in ads for pizza or pasta sauce.

The clichés didn’t end with the silly accents.  In the weirdly distorted version of the story the program tells, Bruno is depicted as an earnest young friar in Naples who was a true seeker after truth.  But DeGrasse Tyson assures us that he “dared to read the books banned by the Church and that was his undoing.”   We then get a sequence of Bruno reading  a copy of Lucretius’ On the Nature of Things which he has hidden under the floorboards of his cell.  The first problem here is that Lucretius’ work was not “banned by the Church” at all and no-one needed to hide it under their floor.  Poggio Bracciolini had published a printed edition of the book a century before Bruno was born and it had never been banned when the medieval manuscripts Bracciolini worked from had been copied nor was it banned once his edition made it widely available.  The idea that the Church banned and/or tried to destroy Lucretius’ work is a myth that Christopher Hitchens liked to repeat and which has been given a lease of popular life via Stephen Greenblatt’s appalling pseudo historical work The Swerve, which somehow won a Pulitzer Prize despite being a pastiche of howlers.

The DeGrasse Tyson cartoon goes on to depict Bruno having his mind opened to the idea of an infinite universe by Lucretius’ book but then being kicked out of his friary by a mob of Disney villain-style Church types who turn up unexpectedly like Monty Python’s Spanish Inquisition.  This, of course, makes for a much better parable than the truth – Lucretius’ work wasn’t “banned by the Church” and Bruno actually ran away from his religious house and wasn’t thrown out for reading naughty books.

It would also have complicated this simplistic cartoon fable to note where Bruno got his ideas about a vast cosmos where the earth was not the centre, where the stars were other suns, where there was a multiplicity of worlds and where some of these other worlds could even have been inhabited just like ours.  Because this was not something Bruno got from Lucretius nor was it something he dreamed up himself in a vision, as the Cosmos cartoon alleges.  It’s something he drew directly from the man he called “the divine Cusanus” – the fifteenth century natural philosopher and theologian Nicholas of Cusa.

If the writers of the series were actually interested in the real history of the origins of scientific thought, there are many people whose stories would have been far more worthy of telling than Bruno – people who actually were proto-scientists.  The writers of the show, Stephen Soter and Sagan’s widow Ann Druyan, seem to have known enough about Bruno to know they could not present him as a scientist and DeGrasse Tyson’s narration does mention that he was “no scientist” at one point.  But they delicately skim over the fact that the guy was, to our way of thinking, a complete mystical loon.  In his defence of the criticism the Bruno sequence has since attracted Soter notes that several  other early science figures also pursued studies that we find abjectly unscientific, such as Newton’s obsessions with alchemy and apocalyptic calculation.  But the difference is that Newton and Kepler pursued those ideas as well as studies that were based on real empirical science, whereas Bruno’s hermetical mysticism, sacred geometry and garbled and largely invented ancient Egyptian religion were all of his studies – he did no actual science at all.

But if they wanted to be truly accurate they should have detailed or even merely acknowledged Bruno’s debt to Nicholas of Cusa, who expounded on a non-finite cosmos without a centre 109 years before Bruno was even born.  Here is Cusanus on the subject in his book De docta ignorantia :

” The universe has no circumference, for if it had a centre and a circumference there would be some and some thing beyond the world, suppositions which are wholly lacking in truth. Since, therefore, it is impossible that the universe should be enclosed within a corporeal centre and corporeal boundary, it is not within our power to understand the universe, whose centre and circumference are God. And though the universe cannot be infinite, nevertheless it cannot be conceived as finite since there are no limits within which it could be confined.”

That’s the insight that the Bruno cartoon attributes solely to Bruno.  So why not attribute it to “the divine Cusanus”?  Well, that would ruin the whole parable.  Because far from being kicked around by grim-looking Disney villains imprisoned and burned at the stake, Cusanus was revered and actually made a cardinal.  So that doesn’t lend itself very well to a moral fable about free-thinking geniuses being oppressed by dogmatic theocrats.

The cartoon then goes on to depict brave Bruno lecturing at Oxford, with grumpy and aristocratic-sounding scholars there objecting to his espousal of Copernicanism and eventually throwing fruit at him and driving him away.  Again, the reality wasn’t quite as worthy.  There is zero record of any objection to heliocentrism and the problem the Oxford scholars had with Bruno was actually his plagiarism of another scholar’s work.  But, again, that doesn’t lend itself to a fable about a pure and persecuted freethinker.

Throughout the cartoon the idea is that he is afflicted because he supports heliocentrism and the idea of an unbounded cosmos  where the earth is not the centre.  As we’ve seen, the latter idea was not new and not controversial.  By the 1580s Copernicus’ heliocentric hypothesis wasn’t particularly new either, though it was more controversial – virtually no astronomers accepted it because it was recognised as having severe scientific flaws.  The important point to remember here is that at  that stage it was not considered heretical by religious authorities, even though some thought it had some potentially bothersome implications.

Copernicus had not even been the first proto-scientist to explore the idea of a moving  earth.  The medieval scholar Nicholas Oresme had analysed the evidence that supported the idea the earth rotated way back in 1377 and regarded it as at least plausible.  The Church didn’t bat an eyelid.  Copernicus’ calculations and his theory had been in circulation long before his opus was published posthumously and and it had interested several prominent churchmen, including Pope Clement VII, who got Johan Widmanstadt to deliver a public lecture on the theory in the Vatican gardens, which the Pope found fascinating.  Nicholas Cardinal Schoenburg then urged Copernicus to publish his full work, though Copernicus delayed not because of any fear of religious persecution but because of the potential reaction of other mathematicians and astronomers.  Heliocentrism didn’t become a religious hot topic until the beginning of the Galileo affair in 1616, a decade and half after Bruno’s death.

Again, the Cosmos writers seem to be at least vaguely aware of all this and so do some fancy footwork to keep their parable on track.  In the cartoon’s depiction of Bruno’s trial we get the first hint that the Church’s beef with Bruno might actually have been to do with ideas that had zero to do with an infinite cosmos, multiple worlds or any cosmological speculations at all.  So the Disney villain Inquisitor reads out a list of accusations such as “questioning the Holy Trinity and the divinity of Jesus Christ” and a few other purely religious charges.  The depiction gives the impression that these are somehow less important or even trumped up accusations, when in fact these are the actual reasons Bruno was burned at the stake, along with others beside.  As horrific as it is to us, denying the virginity of Mary, saying Jesus was merely a magician and denying Transubstantiation did get you burned in 1600 AD, though only if you refused repeated opportunities to recant.

But the cartoon wants to stick to its parable, so they tack on the final and, we are led to believe, most serious charge – “asserting the existence of other worlds”.  As we’ve already seen, however, this was not actually a problem at all.  Here’s NIcholas of Cusa on these other worlds in the book that inspired many of Bruno’s beliefs:

“Life, as it exists on Earth in the form of men, animals and plants, is to be found, let us suppose in a high form in the solar and stellar regions. Rather than think that so many stars and parts of the heavens are uninhabited and that this earth of ours alone is peopled – and that with beings perhaps of an inferior type – we will suppose that in every region there are inhabitants, differing in nature by rank and all owing their origin to God, who is the center and circumference of all stellar regions …. Of the inhabitants then of worlds other than our own we can know still less having no standards by which to appraise them.”

Again, remember that Cusanus was not burned at the stake, he was revered, praised and made a cardinal.

The only mention of other worlds in the accusations against Bruno specifies that he believed in “a plurality of worlds and their eternity“.  It was that last part that was the problem, not subscribing to an idea that a prince of the Church had espoused a century earlier.

The cartoon concludes with DeGrasse Tyson’s caveats about Bruno being “no scientist” and his ideas being no more than a “lucky guess”.  Some commenters seem to think that this somehow absolves the whole sequence of its distortions and that it means the show depicts Bruno only as a martyr to free thought and a lesson on the dangers of dogmatism.  But the problem with the cartoon is that it makes up a silly pastiche of real history, fantasy and oversimplified nonsense to achieve this aim.  The real story of Cusanus would actually have been a much more interesting one to tell and wouldn’t have had the Draper-White inspired baggage of the Bruno myths.  But the whole sequence seems to have had an agenda and a burned heretic story served that agenda’s purpose in a way that a revered and untrammelled medieval cardinal’s story would not have.

The objective here was to make a point about free thought and dogmatism in the context of the culture wars in the US about Creationism.  That Bruno was a believer in God was an idea that was repeated several times in the cartoon, even though he was actually more of a pantheist than anything.  But he is depicted as an open-minded and unconstrained believer who is oppressed and finally killed by the forces of dogmatic literalism.  The cartoon Bruno’s cry to the fruit-throwing Oxford scholars  – “Your God is too small!” – is actually the point of the whole parable.  This entire sequence was aimed at the dogmatic literalists in the American culture war while still trying to appeal to believers, given the majority of the show’s American audience would have been theists.  That’s the framework of this fable and the writers chopped up bits of the actual historical Bruno story and then clumsily forced them into this modern message.

This sequence wasn’t history or anything remotely like it – it was politics, pure and simple.

Which brings me back to my encounter with the statue in the Campo de’Fiori.  The statue was created by Ettore Ferrari and erected in 1889 in the wake of the unification of Italy in the face of Church opposition.  The monument, raised by members of the Grande Orient d’Italia Masonic order, was a deliberate political symbol of anti-clericalism.  Atheists and free thinkers revere it to this day and commemorate Bruno’s execution on Febrary 17 each year.

Of course, anyone who points out that Bruno is a rather ridiculous icon for atheists, given his kooky mystical views and magical practices is usually ignored.  And anyone who has the temerity to point out that he was executed for purely religious ideas and not any speculation about multiple worlds or a non-finite cosmos is usually (bizarrely) told they are somehow justifying his horrific execution.  As I’ve often noted, for people who call themselves rationalists, many of my fellow atheists can be less than rational.  Unfortunately, Neil deGrasse Tyson, Ann Druyan, Steven Soter and Seth MacFarlane’s silly Bruno cartoon will definitely not help in that regard.


Filed under History of Astronomy, Myths of Science, Renaissance Science

A strange defence

This week saw the broadcast of the first episode of the remake of the legendary television series COSMOS, originally hosted by Carl Sagan and now being presented by Neil deGasse Tyson. Although I have now had the chance to view it thanks to the good offices of the man for all things Darwinian, Michael Barton (@darwinsbulldog), I’m not going to blog about it as Tim O’Neill, Renaissance Mathematicus reader and commentator, and fellow invincible warrior in the struggle against bad history of science,  is writing a guest post on the subject, which if all goes well will appear here on next Monday. However this post is directly concerned with one part of the show.

The centrepiece of the episode was an anime style carton on the life and thoughts of infamous Renaissance heretic Giordano Bruno. This immediately led to a raising chorus of voices on Twitter wondering what my views on this would be. Having in the mean time seen it I labelled it on Twitter an “Anime Draper-White for the Twenty-First Century”. For anybody who doesn’t know John William Draper (1811 – 1882) and Andrew Dickson White (1832 – 1918) are the two nineteenth century American academics who created the myth of a war (their term) between science and religion. A myth still unfortunately believed in by many a gnu atheist.  I’m not going to say anything more about this unfortunate piece of animated bollocks, as I’m sure that Tim will comment extensively in his guest post.

However the rest of the Intertubes has not remained silent on the issue and I can recommend the eminently sensible post on the subject by Meg Rosenburg (@trueanomalies) and the wonderfully provocative post by Becky Ferreira (@beckyferreira) “What ‘cosmos’ got wrong about Giordano Bruno, the heretic scientist, which contains the absolutely brilliant description of Bruno: “Bruno was a walking, talking shit storm, with a black belt in burning bridges”.  How I wish that I had coined that sentence!

The debate continued at Discovery Magazine with a blog post by Cory S. Powell, “Did “Cosmos” pick the wrong hero?”, in which Powell suggests that Thomas Digges would have made a better subject for the cartoon than Bruno. Personally I side with Meg Rosenburg who asks whether we need any heroes at all when discussing the history of science; a rhetorical question to which the answer is no.

Powell’s post finally provoked a response from the makers of “Cosmos” in the form of a post by Steven Soter, astrophysicist and co-writer of “Cosmos”, titled The Cosmos of Giordano Bruno (now with added response from Powell) and it is to this post that I now wish to reply, as it contains a number of very questionable statements.

In his second paragraph Soter writes the following:

Powell’s critique dwells on the well-known facts that Bruno was a mystic and an extremely difficult person. Well, so was Isaac Newton, who devoted as much time to alchemy and biblical numerology as to physics. But that has no bearing whatever on his good ideas.

I could write a whole post just about this one paragraph. First off Soter is putting Bruno a man who had one half correct cosmological idea during an intoxicating religious fantasy, that makes you wonder if he’d been hitting the magic mushrooms, with Isaac Newton who produced some of the most important new mathematics, astronomy, and mathematical physics in the history of mankind. That’s one hell of a lopsided analogy Mr Soter! Secondly as anybody knows, who is up to date on his Newton research, or who has simply read some of my blog posts on the man, Newton’s theology and his alchemy did have a massive bearing on his ‘good ideas’.

Soter then corrects Powell as to who first claimed that the universe was infinite, which to be fair Powell got wrong, although neither of them remarks that Lucretius, Bruno’s source, didn’t think of this himself but actually got the idea from the Greek atomists.

We now come to the core of the matter and the reason why Soter et al claim to have included the Bruno cartoon in their show:

Bruno’s originality lies elsewhere. He was indisputably the first person to grasp that the Sun is a star and the stars are other suns with their own planets. That is arguably the greatest idea in the history of astronomy. Before Bruno, none of the other Copernicans ever imagined it.

Leaving aside the hyperbole about ‘the greatest idea in the history of astronomy’, as he says the question is highly debateable, this paragraph still has several issues. Firstly the Greek philosopher Anaxagoras had already suggested that the sun and the stars were one and the same in the fifth century BCE, although he didn’t hypothesise the presence of other planets. Secondly if this was the real reason for including the Bruno cartoon in this episode, why was the main emphasis of the cartoon placed on the Church’s treatment of Bruno as a heretic even to the extent of presenting the Church officials as demons with red glowing eyes, I smell a rat.

If you think I’m misinterpreting the message of the cartoon I offer this comment from Meg Roserburg’s post, Albeit says:

No offense, but I think you’re missing the point here. The moral of the story, as stated in Cosmos, is: don’t let your beliefs stand in the path of reality. Bruno’s necessarily oversimplified story is just a warning about anti-science and dogmatic thinking.

Throughout the Internet you can find similar interpretations, so either the message of the cartoon was other than claimed by Soter or they really made a balls up of scripting it.

Soter than attacks Powell’s suggestion that Thomas Digges should have been featured rather than Bruno, after all he did suggest that the universe is infinite before Bruno. Soter’s argument is a little strange he writes:

But Digges regarded the stars as “the court of the celestial angels” not as the suns of other material earths. And that was a big step backwards. In contrast, Bruno wrote, “the composition of our own stars and world is the same as that as many other stars and worlds as we can see.” His profound intuition had to wait three centuries to be verified by the spectroscope.

First off Digges’ claim that the stars were the court of the celestial angels is just bog standard medieval cosmology, so in that sense is not a step backwards. Secondly Digges wrote and published earlier than Bruno, so in that sense it is also not a step backwards.

That the composition of everything in the cosmos was the same is neither new nor original to Bruno. The Stoics had believed this in antiquity and there had been a major revival in Stoic scientific philosophy in the sixteenth century making Bruno considerably less original on this count than Soter would like to see him.

Soter is also guilty here of quote mining, selecting those parts of Bruno’s fantasy that fit with our modern concepts and quietly ignoring those that don’t. This is a form of presentism known as searching for predecessors. One takes an accepted scientific idea and filters through history to see if somebody had the same idea earlier, then crying eureka and declaring the discovered thinker to be a genius ahead of his or her times. This activity can best be observed in popular histories of atomism where everybody who ever believed that matter consists of some sort of particles are all swept up into one glorious heap and declared to be predecessors of John Dalton. In Bruno’s case one has to ignore the rather inconvenient fact that he thought that the whole of space was filled with identical solar systems placed throughout space at equal intervals, a conception that doesn’t quite fit with our actually understanding of the universe.

Soter now attacks Powell for saying that neither Kepler nor Galileo thought much of Bruno. Soter mocks and ridicules Kepler for believing in a finite universe.  This is ironic given that Soter thinks it is irrelevant that Bruno produced fifty tons of shit including rejecting the use of mathematics in science because he produced one tiny little diamond of thought.

Soter then quote mines again making Kepler to a supporter of Bruno. He correctly quotes a passage from Kepler’s Dissertatio cum Nuncio Sidereo (1610) his response to Galileo’s telescopic discoveries.

What other conclusion shall we draw from this difference, Galileo, than that the fixed stars generate their lights from within, whereas the planets, being opaque, are illuminated from without; that is, to use Bruno’s terms, the former are suns, the latter, moons or planets?

Here Kepler is referring to the difference in the images of planets and stars when viewed through the new invention the telescope. Kepler would here be appearing to support Bruno’s theory and that is the impression that Soter wisher the reader to have but this is actually an illusion. Kepler says let us use Bruno’s term, he doesn’t say let us adopt Bruno’s theory. You might think I’m splitting hairs and that by adopting Bruno’s term Kepler is of course adopting Bruno’s theory but this is very definitely not the case. How can I be so sure? Because Kepler himself tells us so, he does so by evoking what is now known as Olbers’ paradox.  Kepler argues, as did Heinrich Olbers, a German astronomer, in the nineteenth century, that if the heavens were filled with an infinity of suns equally distributed in all direction, as Bruno claimed, then there would never be a night, these suns lighting up the skies twenty-four hours a day. His, incorrect but rational solution, to the paradox was that the Sun and the stars are fundamentally different and thus Bruno was wrong. Far from being a tacit supporter of Bruno’s hypothesis, as Soter would have us believe, Kepler actually refuted it with a good solid, if incorrect, scientific argument. A further irony in this situation is that Kepler was not the first to realise that an infinity of suns would lead to Olbers’ paradox, thus seeming to invalidate Bruno’s hypothesis, Thomas Digges, who hypothesised an infinity of stars before Bruno, also explicitly recognised the problem.

Having abused Kepler Soter now moves on to Galileo accusing him of plagiarism and cowardice, in the process again making a false claim:

Galileo never once mentioned Bruno’s name. Of course in the land of the Inquisition he had good reasons. But in his “Dialogue on the Two Chief World Systems” (the book that got him into deep trouble), he discretely accepted Bruno’s greatest idea, writing that the fixed stars are other suns.

Don’t let anybody tell you that being a pedantic history of science blogger is an easy life. Although I possess two different translations of Galileo’s magnum opus I don’t know it off by heart and was not aware of Galileo “discretely accepting Bruno’s greatest idea”, so I spent about four hours yesterday evening going through every single reference to star, stars or sun listed in the index to the Drake translation comparing with the Finocchiaro translation and searching for further information in five volumes of secondary literature. The only consolation for all of this effort was that I found the passage to which Soter is probably referring. On The Second Day in a discussion on the movement of the heavenly bodies Salviati makes the following observation:

Now behold how nature, favoring our needs and wishes, presents us with two striking conditions no less different than motion and rest; they are lightness and darkness – that is, being brilliant by nature or being obscure and totally lacking in light. Therefore bodies shining with internal and external splendour are very different in nature from bodies deprived of all light. Now the earth is deprived of light; more splendid in itself is the sun, and the fixed stars are no less so. The six moving planets entirely lack light, like the earth; therefore their essence resembles the earth and differs from the sun and the fixed stars: Hence the earth moves and the sun and the stellar sphere are motionless.

This passage is, like the Kepler quote above, very clearly based on Galileo’s telescopic observations of the stars and planet and their respective telescopic images and is not borrowed from Bruno. It is also clear that here Galileo is only referring to the stars and the sun both being self-illuminating, his discussion only treats of one attribute, lightness or darkness, but he doesn’t take the next step of saying that therefore they are the same. He might possibly have thought so but then again he might not. It is also clear here that with his reference to the stellar sphere Galileo s still accepting a traditional bounded finite cosmos.

I now turn to the implicit argument that Galileo didn’t reference Bruno because of the Inquisition, either through caution or, as I provocatively said above, through cowardice. This argument is not unique to Soter but has been used by numerous commentators in the Internet in the last few days. In the Roman Inquisition had, like the FBI, had a Most Wanted list, then during the first part of Galileo’s life Numero Uno on that list would have, without any doubt, been the Servite monk Paolo Sarpi (1552 – 1623).  To quote John Heilbron’s Galileo biography, “…the Servite Sarpi, would present the Vatican with a graver threat than Bruno”. During his years in the Republic of Venice, as professor of mathematics at the University of Padua, Galileo’s best mate and intellectual sparing partner was Sarpi, a fact that was publically well known. Unlike Bruno, who they regarded as a nuisance, the Venetian authorities, who were very proud of their intellectual rebel, Sarpi, who was Venetian born and bred, refused to deliver him to the Roman Inquisitions. Making him even more of a thorn in the side of the Church. Galileo’s close friendship to Sarpi was far more dangerous to his relations with the Church than any casual scientific reference to Bruno would have been. Galileo did not quote Bruno because he didn’t want to, not because he was scared of the Inquisition.

It is worth noting in this context that when Galileo applied for and was granted the position of court philosophicus and mathematicus to the Medici in Florence his Sarpian friends in Venice warned him against leaving the comparatively safe haven of thr Republic, where he was free to think and say almost anything he liked, for the shark infested waters of court intrigue and religious orthodoxy of Florence and Rome. However fame, fortune and social status were more important to Galileo than freedom of thought and speech so he ignored his friends’ warnings with the well known historical consequences.

To close this already over long post I would like to address a historiographical point related to Soter’s deification of Bruno in the history of science. Wirkungsgeschichte is a German term that refers to the historical impact of a scientific theory, invention, or discovery. Some ideas make little or no impact and disappear from the historical stage requiring them to be rediscovered at a later date. A classic example of this is the correct explanation of the cause of the rainbow. Theodoric of Freiberg discovered the correct explanation through empirical experiments in the thirteenth century. However his discovery had almost no impact and got lost, meaning that it wasn’t until the seventeenth century, when Descartes rediscovered it, that the correct explanation of the rainbow became generally known. Bruno’s lucky guess that the stars are suns or that the sun is a star had almost no impact and was largely ignored and forgotten. This makes him in a historical sense a dubious figure to elevate to the status of a scientific hero, as Soter apparently wished to do with his very strange animation in the COSMOS broadcast.


Filed under History of Astronomy, History of science, Myths of Science, Renaissance Science

Rehabilitating Simon Marius


The Ansbach court mathematicus, Simon Marius (1573-1624) acquired a telescope in 1609 and began to make astronomical observations. These proved to be very fruitful and he discovered the four largest moons of Jupiter just one day later than Galileo Galilei. Unlike his Tuscan rival, Marius did not rush into print, the world first becoming aware of his discoveries when he published his magnum opus, Mundus Iovialis, in 1614*. This of course led to Galileo accusing Marius of plagiarism vitriolically in his Il Saggiatore in 1623. Being by now the most famous astronomer in Europe, Galileo’s charge stuck ruining Marius’ reputation down to the present day, although he was shown to be innocent at the beginning of the twentieth century.

2014 brings the four hundredth anniversary of the publication of Mundus Iovialis. To celebrate this anniversary the Nürnberger Astronomische Gesellschaft e.V. (NAG) with the active support of the municipal authorities of Gunzenhausen (his place of birth), Ansbach and Nürnberg as well as the Friedrich-Alexander-University of Erlangen-Nürnberg, the Julius-Maximilians-University of Würzburg, the University of Hamburg, the Hochschule Ansbach, the Technische Hochschule Nürnberg Georg Simon Ohm and the Max-Planck-Institute for the History of Science Berlin together with a whole raft full of sponsors and active and passive partners is presenting a wide range of activities throughout the whole year.

Today, 18th February, is the four hundredth anniversary of the signing of the dedication in the Mundus Iovialis to celebrate which the Simon Marius Internet Portal is being officially launched.

This internet presence is intended to be a guide through the anniversary year of 2014 and will bring together electronically retrievable sources, secondary literature, lectures and news on Simon Marius and – whenever possible – provide convenient links. We the initiators invite you the public to make use of this multilingual portal and also to make your own contributions.

The high point of the year will be a one day conference on the life and work of Simon Marius, Simon Marius und seine Zeit, which will be held in the Nicolaus-Copernicus-Planetarium in Nürnberg on Saturday, 20th September 2014. The proceedings of this conference will be published in book form, hopefully in 2015.

* He had already published his discovery of the moons of Jupiter in his Prognosticon Astrologicum auf das Jahr 1612however this was almost certainly only distributed locally in  Southern Germany and Galileo and the rest of the astronomical community of the period were not aware of its existence.


Filed under History of Astronomy, Renaissance Science

A double heliocentrism anniversary?

Georg Joachim Rheticus was born 500 years ago today in Feldkirch, now in Austria, on 16th February 1514, as Dennis Danielson put it in the title of his excellent Rheticus biography, he was the first Copernican. [1] It was Rheticus who travelled to Frauenburg in 1539 and over many months persuaded Copernicus to publish his De revolutionibus, publishing his own Narratio prima, to test the water for the heliocentric hypothesis in 1540.

Rheticus' Horoscope taken from Danielson The First Copernican p. 16

Rheticus’ Horoscope taken from Danielson The First Copernican p. 16

Rheticus’ name will always be associated with that of Copernicus and heliocentrism.  Another who is inseparably bound up with Copernicus and heliocentrism is Galileo Galilei who celebrated his 450th birthday yesterday, or did he? All over the Internet people were celebrating Galileo’s 450th birthday yesterday, the 15th February, Both the MacTutor History of Mathematics article and the English Wikipedia give his birthdate as 15th February 1564, the latter citing Galileo at Work by Stillman Drake, the Grand Seignior of Galileo studies, but was it? Already on Thursday last week as people were gearing up for the great day Lorenzo Smerillo of Montclair State University pointed out on the History of Astronomy Mailing List that Galileo was actually born on the 16th February and not the 15th.  Somewhat confused, I turned to the two most recent   scholarly biographies of Galileo, David Wootton’s Galileo Watcher of the Skies[2] and John Heilbron’s Galileo[3]; the former says the 15th, the latter the 16th. Interestingly both refer to Galileo’s horoscope, which he cast himself. Another Galileo expert William Shea gives the birthdate in his Galileo Selected Writings, as the 16th and in a footnote explains the reason for the confusion, the same one that Smerillo had already given and which I will now explain.

Galileo's Horoscope

Galileo’s Horoscope

As you can see Galileo’s horoscope gives the date and time of birth twice:

1564. 15. febr. h. 22.30. lat. 42. 30

16. febr. h. 4. pm


The first set of figures are given in Italian hours, which follow the Islamic and Jewish custom of numbering the hours of the day from sunset. Sunset on the 15th February in Northern Italy was at 5:30 pm so the 22.30 hour on the 15th would be 4 pm on the 16th. This is of course the second set of figures giving the date and time of birth in French hours. This shows clearly that Galileo was born on the 16th not the 15th.  The 3.30 is probably an error estimate based on uncertainty as to the time of sunset.

Confusingly Wootton argues against this interpretation insisting on the 15th in a complex discussion of the subject.[4]

Our double anniversary is however somewhat confused by another piece of calendrical confusion. Both of our heliocentric astronomers were born before the calendar reform so their birthdates are given according to the Julian Calendar, this of course means that our double anniversary is not actually today but first on the 26th February.

Just to throw another spanner into the works, both of the birthdates are taken from Renaissance horoscopes making them instantly suspect, why? It was a common practice in the Renaissance for astrologers to rectify horoscopes. This was the practice of adjusting times of birth by hours and even sometimes a whole day to make the resulting horoscope more harmonious with the real life of the horoscope’s subject. Rheticus for example was known to be an adherent of this practice.

[1] Dennis Danielson, The First Copernican, Georg Joachim Rheticus and the Rise of the Copernican Revolution, Walker and co., New York, 2006

[2] David Wootton, Galileo Watcher of the Skies, Yale University Press, New Haven and London, 2010

[3] J. L. Heilbron, Galileo, Oxford University Press, Oxford, 2010

[4] David Wootton, Accuracy and Galileo: A Case Study in Quantification and the Scientific Revolution, The Journal of the Historical Society, Vol.10, 2010 pp. 43-55


Filed under History of Astronomy, Uncategorized

An unfortunate conclusion.

On Twitter I follow three accounts that tweet daily titbits out of the history of mathematics, the Mathematical Association of America (@maanow), the British Society for the History of Mathematics (@mathshistory) and my good friend Pat Ballew (@OnThisDayinMathematics).  Yesterday both Pat and the MAA tweeted links to a brief paragraph about the Renaissance humanist scholar Andreas Dudith. The MAA’s paragraph, which I read first, was the following:

Andreas Dudith (1533-1589), mathematician and opponent of astrology, argued in a letter that observations of the comet of 1577 proved the Aristotelian explanation fallacious (for Aristotle, comets were accidental exhalations of hot air from the earth that rise in the sublunar sphere). Dudith’s use of mathematically precise observations to criticize a general physical theory of Aristotle foreshadowed Galileo’s work fifty years later.

Pat’s almost identical offering was the following:

Andreas Dudith (1533–1589), mathematician and opponent of astrology, argued in a letter that observations of the comet of 1577 proved the Aristotelian explanation fallacious (for Aristotle, comets were accidental exhalations of hot air from the earth that rise in the sublunar sphere). Dudith’s use of mathematically precise observations to criticize a general physical theory of Aristotle betokens Galileo’s work fifty years later.

Although Pat gives his source as the maths history website from V. Frederick Rickey they obviously both have a common source, namely the Dudith article in the Dictionary of Scientific Biography written by the historian of Renaissance mathematics, Paul Lawrence Rose.

The first problem with this account as presented here is that Dudith in his letter was not referring to his own observations but to those of his friend and correspondent Thaddaeus Hagecius, personal physician to the Holy Roman Emperors in Prague who was also a correspondent of Tycho Brahe and later a friend and colleague of Kepler. The second problem is that Hagecius, and through him Dudith, were by no means the only people to accept that parallax measurements showed comets to be supra-lunar thus contradicting the Aristotelian theory of comets, as seems to be implied here. Amongst others, both Tycho and Michael Maestlin, Kepler’s teacher, who were much more influential than Dudith, had also reached this conclusion. In fact much earlier in the sixteenth century, based on their observations of the 1530s comets, Gemma Frisius, Jean Pena, Girolamo Fracastoro and Gerolamo Cardano had already reached the same conclusion. In fact the intensive observations and parallax measurements of the 1577 comet were to determine if Frisius et al. were correct or not in their deductions. In his letter from 19th January 1581 Dudith is merely joining a fairly large and influential choir.

The real problem in this brief account is to be found in the conclusion. A conclusion that is to be found in the Paul Rose original:

Dudith’s use of a mathematically precise observation to criticize a general physical theory of Aristotle’s betokens the same kind of dissatisfaction with Aristotelian physical doctrines that was most eloquently expounded in the works of Galileo fifty years later.

Whilst it is true that Galileo replaced Aristotle’s doctrine on falling objects with his own mathematical laws of fall[1] obtained or at least confirmed through ingenious physical experiments his record on comets was to say the least embarrassing making the comparison here highly questionable.

In 1618 the Jesuit astronomer Orazio Grassi showed by observation and parallax measurement that the comet of that year was indeed supra-lunar driving another nail in the coffin of the Aristotelian theory of comets. Galileo, who due to illness had been unable to observe the comet, was urged by his claque to enter the arena with his opinion on the nature of comets. Galileo then famously launched an unprovoked and extremely vitriolic attack on Grassi condemning his work and defending what was basically a version of the Aristotelian theory. It was one of Galileo’s less glorious moments, far from using mathematic to criticise a doctrine of Aristotle’s Galileo was defending Aristotle’s theory of comets against an astronomer who had used mathematic to disprove it.




[1] It should be pointed out that the essence of Galileo’s laws of fall can be found in the work of Giambattista Bendetti, who by a strange coincidence died on 20th January 1590, a couple of decades earlier.


Filed under History of Astronomy, History of Mathematics

Dying to make life easier for historians.

There is a clichéd view of history encouraged by bad teaching that presents the subject as the memorising of long lists of dates that somebody has designated as being significant, 55 BC, 1066, 1492, 1687, 1859, 1914 etc., etc. Now whilst in reality history is much more concerned with what happened and why it happened than with when it happened dates are the scaffolding on which historians hang up their historical facts for inspection.

When presenting biographies of scientists two key dates that the historical biographer has to remember are those of the birth and the death of her or his subject. One of my favourite Renaissance mathematici mathematics teacher, astronomer, astrologer, cartographer and globe maker, Johannes Schöner, about whom I have already blogged in the past, made life easier for historians by dying on his seventieth birthday. He was born on 16th January 1477 in Karlstadt am Main and died on 16th January 1547 in Nürnberg.  This means one only has to remember his birthdate and them simply add seventy to get his date of death.


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Filed under History of Astrology, History of Astronomy, History of Cartography, History of Mathematics, Renaissance Science

What Isaac actually asked the apple.

Yesterday on my twitter stream people were retweeting the following quote:

“Millions saw the apple fall, but Newton asked why.” —Bernard Baruch

For those who don’t know, Bernard Baruch was an American financier and presidential advisor. I can only assume that those who retweeted it did so because they believe that it is in some way significant. As a historian of science I find it is significant because it is fundamentally wrong in two different ways and because it perpetuates a false understanding of Newton’s apple story. For the purposes of this post I shall ignore the historical debate about the truth or falsity of the apple story, an interesting discussion of which you can read here in the comments, and just assume that it is true. I should however point out that in the story, as told by Newton to at least two different people, he was not hit on the head by the apple and he did not in a blinding flash of inspiration discover the inverse square law of gravity. Both of these commonly held beliefs are myths created in the centuries after Newton’s death.

Our quote above implies that of all the millions of people who saw apples, or any other objects for that matter, fall, Newton was the first or even perhaps the only one to ask why. This is of course complete and utter rubbish people have been asking why objects fall probably ever since the hominoid brain became capable of some sort of primitive thought. In the western world the answer to this question that was most widely accepted in the centuries before Newton was born was the one supplied by Aristotle. Aristotle thought that objects fall because it was in their nature to do so. They had a longing, desire, instinct or whatever you choose to call it to return to their natural resting place the earth. This is of course an animistic theory of matter attributing as it does some sort of spirit to matter to fulfil a desire.

Aristotle’s answer stems from his theory of the elements of matter that he inherited from Empedocles. According to this theory all matter on the earth consisted of varying mixtures of four elements: earth, water, fire and air. In an ideal world they would be totally separated, a sphere of earth enclosed in a sphere of water, enclosed in a sphere of air, which in turn was enclosed in a sphere of fire. Outside of the sphere of fire the heavens consisted of a fifth pure element, aether or as it became known in Latin the quintessence. In our world objects consist of mixtures of the four elements, which given the chance strive to return to their natural position in the scheme of things. Heavy objects, consisting as they do largely of earth and water, strive downwards towards the earth light objects such as smoke or fire strive upwards.

To understand what Isaac did ask the apple we have to take a brief look at the two thousand years between Aristotle and Newton.

Ignoring for a moment the Stoics, nobody really challenged the Aristotelian elemental theory, which is metaphysical in nature but over the centuries they did challenge his physical theory of movement. Before moving on we should point out that Aristotle said that vertical, upwards or downwards, movement on the earth was natural and all other movement was unnatural or violent, whereas in the heavens circular movement was natural.

Already in the sixth century CE John Philoponus began to question and criticise Aristotle’s physical laws of motion. An attitude that was taken up and extended by the Islamic scholars in the Middle Ages. Following the lead of their Islamic colleagues the so-called Paris physicists of the fourteenth century developed the impulse theory, which said that when an object was thrown the thrower imparted an impulse to the object which carried it through the air gradually being exhausted, until when spent the object fell to the ground. Slightly earlier their Oxford colleagues, the Calculatores of Merton College had in fact discovered Galileo’s mathematical law of fall: The two theories together providing a quasi-mathematical explanation of movement, at least here on the earth.

You might be wondering what all of this has to do with Isaac and his apple but you should have a little patience we will arrive in Grantham in due course.

In the sixteenth century various mathematicians such as Tartaglia and Benedetti extended the mathematical investigation of movement, the latter anticipating Galileo in almost all of his famous discoveries. At the beginning of the seventeenth century Simon Stevin and Galileo deepened these studies once more the latter developing very elegant experiments to demonstrate and confirm the laws of fall, which were later in the century confirmed by Riccioli. Meanwhile their contemporary Kepler was the first to replace the Aristotelian animistic concept of movement with one driven by a non-living force, even if it was not very clear what force is. During the seventeenth century others such as Beeckman, Descartes, Borelli and Huygens further developed Kepler’s concept of force, meanwhile banning Aristotle’s moving spirits out of their mechanistical philosophy. Galileo, Beeckman and Descartes replaced the medieval impulse theory with the theory of inertia, which says that objects in a vacuum will either remain at rest or continue to travel in a straight line unless acted upon by a force. Galileo, who still hung on the Greek concept of perfect circular motion, had problems with the straight-line bit but Beeckman and Descartes straightened him out. The theory of inertia was to become Newton’s first law of motion.

We have now finally arrived at that idyllic summer afternoon in Grantham in 1666, as the young Isaac Newton, home from university to avoid the plague, whilst lying in his mother’s garden contemplating the universe, as one does, chanced to see an apple falling from a tree. Newton didn’t ask why it fell, but set off on a much more interesting, complicated and fruitful line of speculation. Newton’s line of thought went something like this. If Descartes is right with his theory of inertia, in those days young Isaac was still a fan of the Gallic philosopher, then there must be some force pulling the moon down towards the earth and preventing it shooting off in a straight line at a tangent to its orbit. What if, he thought, the force that holds the moon in its orbit and the force that cause the apple to fall to the ground were one and the same? This frighteningly simple thought is the germ out of which Newton’s theory of universal gravity and his masterpiece the Principia grew. That growth taking several years and a lot of very hard work. No instant discoveries here.

Being somewhat of a mathematical genius, young Isaac did a quick back of an envelope calculation and see here his theory didn’t fit! They weren’t the same force at all! What had gone wrong? In fact there was nothing wrong with Newton’s theory at all but the figure that he had for the size of the earth was inaccurate enough to throw his calculations. As a side note, although the expression back of an envelope calculation is just a turn of phrase in Newton’s case it was often very near the truth. In Newton’s papers there are mathematical calculations scribbled on shopping lists, in the margins of letters, in fact on any and every available scrap of paper that happened to be in the moment at hand.

Newton didn’t forget his idea and later when he repeated those calculations with the brand new accurate figures for the size of the earth supplied by Picard he could indeed show that the chain of thought inspired by that tumbling apple had indeed been correct.



Filed under History of Astronomy, History of Mathematics, History of Physics, History of science, Myths of Science, Newton