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The first English professor of mathematics

From its origins the word professor refers to someone who professes to know something about a given subject. In the medieval universities undergraduates started their studies in the arts faculty, where they nominally learnt the seven liberal arts (the trivium consisting of grammar, logic and rhetoric and the quadrivium consisting of arithmetic, geometry, astronomy and music) and philosophy. This course of studies closed with the Bachelor of Arts or BA. Most students left the university at this point, those that stayed continued on the arts faculty working towards the Master of Arts of MA, the basic teaching qualification for the university. These masters would then teach the undergraduate courses on the arts faculty whilst simultaneously studying for a doctorate on one of the higher faculties, medicine, law or theology. The normal practice was to distribute the undergraduate teaching duties by drawing lots, the mathematics courses being regarded as having drawn the short straw. The professors were scholars who were specifically designated to teach a particular course of studies, principally in the higher faculties but with time for some courses in the arts faculty. Such dedicated teaching positions were often funded by special endowments from rulers or high-ranking church officials. All the way down to the Renaissance there were no professorships for the mathematical disciplines; first with the rise of astrological medicine or iatromathematics in the fifteenth century were professorships created for the mathematical disciplines, which were effectively chairs for astrology. This process began on the humanist Renaissance universities of Northern Italy with the other European countries slowly following their lead. In these developments the two English universities, Oxford and Cambridge, lagged behind their continental rivals. There were no dedicated professorships for mathematics before the 1590s. Those English scholars who wanted advanced instruction in mathematics, such as John Dee or Henry Savile, had to find this at continental universities.

When he died Thomas Gresham (1519–1579), he of Gresham’s law in economics, merchant, founder of the Royal Exchange and financial manager for the English crown, left the bulk of his fortune for the foundation of a college in London where seven professors should read lectures in both Latin and English, on each day of the week, in astronomy, geometry, physic, law, divinity, rhetoric and music. Gresham College was established in 1597 and Henry Briggs was appointed in 1596 as the first Gresham professor of geometry and as such the first English professor of mathematics.

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Sir Thomas Gresham by Anthonis Mor Rijksmuseum

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Gresham College 1740 Source: Wikimedia Commons

Henry Briggs was born in Warley near Halifax in Yorkshire the son of the farmer Thomas Briggs and baptised 23 February 1561. He matriculated at St John’s College Cambridge in 1578, graduating BA in 1581 and MA 1585 becoming a fellow of the college in 1588. He was appointed mathematicus examinator in 1592 and in the same year become Linacre lecturer in physic. Although he was Gresham Professor of geometry Brigg’s principle interests were astronomy, geography and navigation and he maintained close contact with the mathematical practitioners of London, in particular the cartographer, navigator Edward Wright. In 1602 he published A Table to Find the Height of the Pole and in 1610 Tables for the Improvement of Navigation. Briggs also corresponded on mathematical topics with James Ussher.

In 1614 John Napier published the first logarithm tables his Mirifici logarithmorum canonis descripto. In 1616 Briggs wrote to Ussher:

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Napper [Napier], Lord of Markinston, hath set my Head and Hands a Work, with his new and admirable Logarithms. I hope to see him this Summer if it pleases God, for I never saw Book which pleased me better, or made me more wonder.

Logarithms vastly simplified the complex calculations needed in both astronomy and navigation and Briggs would make their improvement his life’s work. Briggs took up contact with Napier and in 1616 he undertook the arduous four-day journey from London to Edinburgh to meet with Napier; a journey that he repeated in the following year.

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Napier’s logarithms were based on approximately 1/e. Briggs convinced Napier that logarithms base ten with log 10 = 1 would be more useful and set about calculating a new set of log tables his Logarithmorum Chillias Prima, which was published in 1617.

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In 1616 and 1618 Briggs published, A description of an Instrumental Table to find the part proportional, devised by Mr Edward Wright, which is the mathematics required to produce a Mercator projection map or sea chart.

In 1619 Henry Savile set up the first university chairs for geometry and astronomy at Oxford University and after having delivered the first geometry lecture himself handed over the chair for geometry to Henry Briggs.

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Henry Savile Source: Wikimedia Commons

Briggs produced an extended set of log tables base ten calculated to fourteen places of decimals in 1624 his, Arithmetica Logarithmica. He also calculated tables of logarithmic sines and tangents to ten places of decimals, which were published posthumously.

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In his rooms at Gresham college it was Briggs who started the habit of holding meetings of all those interested in the mathematical sciences. These meetings were continued by both his successors as professor for geometry as well as the holders of the Gresham professorship for astronomy. These meetings would go on to found the core of what became the Royal Society, which for most of its first four decades was also at home in Gresham College.

Briggs died in 1630 and now that the ubiquitous school log tables, mine were always in my school satchel, have been made obsolete by the electronic pocket calculator Briggs’ great contribution to the mathematical sciences is slowly slipping into the fog of forgetfulness but in his time his calculatory contributions were of immense importance and he is a central figure in the history of English mathematics in the first half of the seventeenth century and deserves to be honoured as such, not just for the log tables but also for his active and intense support of the small but active mathematical community and not least as the first English professor of mathematics.

 

 

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No he didn’t, no they didn’t and no it wasn’t.

Sometime I just wonder why I bother. I sit in my little corner of the Internet trying to convince people to ditch the myths that they believe to be history of science and instead to replace them with the true facts. Then along comes the once upon a time noble BBC and post on their website, History Extra, the article 12 giant leaps for mankind – from carnivorism to Magna Carta in which:

We asked 12 historians to nominate alternative moments in the past that they consider to be great leaps for mankind. Interviews by Rob Attar

Several of the twelve historians are suitably famous: For example Felipe Fernández-Armesto, Jerry Brotton, Allan Chapman, Patricia Fara and Jim Bennett all of whose work I know and respect.

 

However a Colin Russell, who I don’t know and can’t find with the help of Wikipedia and Google, delivered up: Galileo explores the heavens with his telescope – Italy, 1609, mythology pure:

I will make a line-by-line analysis of Collin Russell’s words of wisdom:

When Galileo became the first person to turn a telescope to the skies, it changed our view of the universe.

 Galileo was not the first person to turn a telescope to the skies. Already in the last week of September 1608 as Hans Lipperhey demonstrated his new invention to the assembled prominence in The Hague it was turned to the skies “and even the stars which normally are not visible for us, because of the scanty proportion and feeble sight of our eyes, can be seen with this instrument.” The quote is taken from Embassies of the King of Siam Sent to his Excellency Prince Maurits, Arrived in The Hague on 10 September 1608, the French newsletter that carried the news of the advent of the telescope throughout Europe.

If instead he meant the first astronomer/astrologer/mathematician/natural philosopher or whatever then that honour goes to Thomas Harriot and not to Galileo. There is fairly strong but not conclusive evidence that Simon Marius also turned his telescope to the heavens before Galileo.

 He discovered new facts about the Sun, Moon and planets, which were totally incompatible with the old theory that the sky above Earth was unchanging and perfect.

 This sentence is actually true but that had been substantial evidence that the heavens were not unchanging throughout the sixteenth century, before the invention of the telescope, with the observation of various comets and a nova all of which were determined by various expert observers to be supraluna, the earliest of these already in the 1530s. The telescopic observations merely added more evidence of this fact.

Instead they strongly supported the rival and newer heliocentric theory of Copernicus.

 These telescopic observations seriously damaged the accepted Aristotelian cosmology but had not effect on the prevailing Ptolemaic geocentric astronomy and in no way supported the heliocentric theory of Copernicus. The telescopic observations of the phases of Venus, not mentioned by Russell, made contemporaneously by Harriot, Marius, Lembo and Galileo were not compatible with the Ptolemaic geocentric astronomy but were just as compatible with a Tychonic or semi-Tychonic geo-heliocentric system as with a heliocentric one and for various other empirical reasons most astronomers chose the geo-heliocentric models.

Galileo’s telescope stimulated him to write his contentious book Two World Systems (1630), which more than anything else helped to establish Copernicanism.

 Initially Galileo’s telescope stimulated him to write his Sidereus Nuncius (1610), which, as he was well aware, offered no conclusive support for a heliocentric model. His Dialogo (Dialogue concerning the Two Chief World System) is not centred on the telescopic observations, although the play an important role, but on his ill-advised and ill-fated theory of the tides; an ingenious but fatally flawed empirical theory supposed to support a moving earth. The book also suffers from the fact that it pits the Ptolemaic geocentric model against the Copernican heliocentric one, whereas in fact as it was published the two chief world systems were a Tychonic geo-heliocentric one with diurnal rotation and Kepler’s elliptical heliocentric system. Galileo was simply behind the times!

This book in no way “more than anything else helped to establish Copernicanism.” Firstly Copernicanism was never established but had by 1630 been superceded by Kepler’s elliptical astronomy and secondly the two books that did most to establish a heliocentric model, before there was actually empirical proof for it, were Kepler’s Epitome Astronomiae Copernicanae, an unfortunate title as it is about his own system and not Copernicus’, and his Tabulae Rudolphinae.

Once again we have someone incorrectly attributing the whole of early telescopic astronomy to Galileo. I would in fact agree with Russell that the invention of the telescope and its application to astronomy could be considered as a “giant leap for mankind”, however to attribute that giant leap to Galileo alone is pure hagiography and historically false. I would have started with the invention of the telescope by Lipperhey and others in 1608 and then moved on to its early application in astronomy by Harriot, Marius, Galileo, Lembo, Grienberger, and others. In fact it is the very fact that those early observations were made independently by several astronomers that led to them being accepted very rapidly by the astronomical community.

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The truth obscured

In my previous post I wrote about on this day Internet posting and why I personally do it. At the end of my post I warned of bad factually false postings under this tag and as fate would have it, as I was writing my post I stumbled across just such an example.

The calendar style on this day blog site Today in Science History had for 24 January under their Events rubric the following entry, which is liberally peppered with very avoidable errors:

In 1544, a solar eclipse was viewed at Louvain, which was later depicted in the first published book illustration of the camera obscura in use. Dutch mathematician and astronomer Reinerus Gemma-Frisius viewed a solar eclipse using a hole in one wall of a pavillion [sic] to project the sun’s image upside down onto the opposite wall.

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Gemma Frisius’ illustration of a camera obscura used to observe the sun

This first paragraph already contains a number of errors. Gemma Frisius, I’ll come back to the name, was in fact Frisian and not Dutch; In fact The Netherlands as they exist now didn’t exist when he was born and his birthplace, Dokkum, was in the Habsburg Netherlands. He was born Jemme Reinierzoon or Jemma son of Reinier to poor parents in Dokkum in Friesland on 9th Dec 1508. His nom de plume Gemma Frisius is a Latinised onomatopoeic version of his birth name plus the toponym Frisius for Friesland. The Reinerus is a piece of pure invention, one of several, from people who don’t understand his actual name.

The post continues as follows:

He published the first illustration of a camera obscura, depicting his method of observation of the eclipse in De Radio Astronomica et Geometrica (1545). Several astronomers made use of such a device in the early part of the 16th century. Both Johannes Kepler and Christopher Scheiner used a camera obscura to study the activity of sunspots. The technique was known to Aristotle (Problems, ca. 330 BC).

The claim that, “Several astronomers made use of such a device in the early part of the 16th century” is more that somewhat dubious, as apart from Leonard’s descriptions of the camera obscura, which didn’t become known till the eighteenth century, all of the known sixteenth century descriptions of the instrument are post Gemma Frisius, so the later part and not the early part of the century.

The next sentence is simple wrong. Johannes Kepler never studied the activity of sunspots an astronomical sport that he left to others. He did however use a camera obscura of his own design set up in a tent to view solar eclipses in Graz on 30 June 1601 and in Prague on 12 October 1605. Infamously whilst he was busy observing the solar eclipse on the market place in Graz in 1601 a thief stole his purse with thirty silver florins. Whilst still with Kepler, if you are going to talk about the use of the camera obscura in Early Modern astronomy then you really should mention the fact that Kepler coined the name camera obscura.

Christoph (not Christopher) Scheiner did observe sunspot activity; in fact he was the leading observer of such activity in the early seventeenth century publishing his results in his Rosa Ursina sive Sol (1626–1630). However, he didn’t use a camera obscura to do so, he used his machine helioscopica (helioscope) a telescope that he designed to project images of the sun onto a sheet of paper. Interesting in this context is that Scheiner’s helioscope was probably the first ever Keplerian or astronomical telescope, it being irrelevant if the projected image is right way up or inverted.

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Christoph Scheiner’s machine helioscopica Source: Wikimedia Commons

Some might object that the method is not substantially different to the use of the camera obscura but although the principle is the same the two instruments are distinct and different and should not be thrown haphazardly together.

I also have problems with the sentence, the technique was known to Aristotle. I would be happier if it read, the phenomenon was known to Aristotle. What he actually wrote in Problems Book XV was the following:

“Why is it that when the sun passes through quadrilaterals, as for instance in wickerwork, it does not produce a figure rectangular in shape but circular?”

 and

 “Why is it that an eclipse of the sun, if one looks at it through a sieve or through leaves, such as a plane-tree or other broadleaved tree, or if one joins the fingers of one hand over the fingers of the other, the rays are crescent-shaped where they reach the earth? Is it for the same reason as that when light shines through a rectangular peep-hole, it appears circular in the form of a cone?”

From these passages it is obvious that Aristotle never actually constructed a camera obscura and although he observed the phenomenon on which it is based he never really understood it.

All of the above might appear to be nit picking to some but a fundamental principle of all historiography is first get facts right and the quoted paragraphs gets almost all of their facts wrong.

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On this day…

Last week my #histsci soul sisterTM Rebekah “Becky” Higgitt started a thread on Twitter with the following:

Robert Boyle and Robert Burns born #otd – although presumably one on old style calendar, one on the new

Dan Flett responded:

Yeah I’m always wondering how we go about calling something “on this day” when there are different calendars involved.

Becky:

I guess that it’s pretty arbitrary anyway, so doesn’t matter much, but interests me that anniversaries have appeal

Now the problem of different calendars and especially the old style/new style confusion is one that I have dealt with more than once on this blog; in fact Becky drew my attention to the thread by linking to two of my old posts. This recent one from the last winter solstice and an earlier one about just such an apparent coincidence, which wasn’t, that started the thread. I threw in my post on Newton’s date of death for good measure.

Of course the whole problem gets much more complicated the further one moves back in time and the further one moves away from the European sphere of influence. How can you be sure that birth, death or even date given for someone in ancient Greece has been correctly converted to the current Georgian calendar from whichever local Greek lunar calendar it was originally recorded on? The same applies to dates from Islamic, Indian Chinese and a multitude of other pre-modern histories.

However there is another aspect to this debate that is reflected by Becky’s comment, “but interests me that anniversaries have appeal”. That they do have is amply illustrated on both Twitter and Facebook by the number of individuals and organisations that regularly and consistently post ‘on this day’ (#otd) posts. This includes important scientific institutions such as the Royal Society, Chemical Heritage Foundation, Linda Hall Library and ESA as well as many websites dedicated to producing all year round on this day calendars such as On This Day in Science History, SciHi, or On This Day in Math. Many individual bloggers such as Paige Madison (Fossil History), David Bressan and of course I do the same. Becky’s comment implicitly questions this habit by explicitly questioning the appeal of such postings. Irish physicist and historian of physics, Cormac O Rafferty, reader and occasional commentator on this blog, says quite openly that he doesn’t understand why people do it. I can’t of course speak for anybody else but I can at least try to explain why I do it.

Although I tend to concentrate on Europe in the Early Modern Period my interest in all things mathematical and scientific range from the Neolithic to the twentieth century and all around the globe. For my blogging there are no plans, concepts, schedules or whatever, I try to blog once a week on average and then I mostly just write spontaneously about something that has caught my attention during the preceding seven days. Very often it is some sort of anniversary, a date of birth or death, a publication date, a date of discovery or invention that does just that, catch my attention. Then I tend to post on or near that anniversary. It really is as simple as that; the anniversary is really just a hook to hang a subject that interests me on. Given that I have now been blogging for well over eight years and have thereby accumulated quite an archive of potential blog posts and I seem to attract new readers here and followers on Twitter and Facebook, I see it as a service to the more recent newbies to draw their attention to one or other old post. The easiest way to do this is once again the ‘on this day’ trick. When a #histSTM anniversary comes up about which I have written in the past then I promote the old post on Twitter and Facebook.

Of course I also write posts from time to time that are not attached to a particular date but they tend like this one to be more general, methodological or even philosophical; these also get promoted on social media when the topic comes up in Internet discussions.

In reality, at least as far as I am concerned, the ‘on this day’ tag is just a lazy way of picking out a subject to write a post about from the vast ocean of potential topics that history has to offer. One danger of this approach is however that others take the lazy way out and perpetuate false facts and myths under the ‘on this day’ tag, something that I would naturally never do.

 

 

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Isaac Beeckman – candle maker, hydro-engineer, schoolteacher, lens grinder, natural philosopher…

I first stumbled across Isaac Beeckman when I was learning about the early history of the telescope. In his Journal, about which more later, he wrote how Johannes Zachariassen, who was teaching him lens grinding, explained how he and his father Zacharias Janssen invented the Dutch or Galilean telescope, the microscope and the long or astronomical telescope. Despite various dubious aspects to this claim this was one of the sources that Cornelis de Waard used at the beginning of the twentieth century in the first modern history of the telescope in naming Zacharias Janssen as one of the three inventors of the telescope. Modern research has shown that Janssen could not have been one of the inventors of the telescope.

The second time I came across Beeckman is when I discovered, I can’t remember where, that Newton’s first law of motion, the law of inertia, was not, as often claimed, taken from Galileo or from Galileo via Descartes but from Beeckman via Descartes. This is something that I have over the years pointed out also pointing out that Galileo’s law of inertia was false because he believed that natural motion was always circular whereas Beeckman hypothesised, correctly, that it is linear. I have also been systematically criticised over the years by people saying, also correctly, that Beeckman believed that linear and circular motion are both natural motion, of which also more later.

For a long time this was almost the sum total of my knowledge of Isaac Beeckman but it was enough to place him on the very long list of people I would like to know much more about. Recently Linda Hall Library had Beeckman as their scientist of the day and I discovered that Klaas van Berkel had written a biography of Beeckman, which appeared in English in 2013[1]. Now I know Klaas van Berkel and know that he is an excellent historian of science, so I acquired his book and having now read it I know a lot about Isaac Beeckman, a truly fascinating seventeenth century scholar.

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The cover illustration is Interior of a Room with a Young Man Seated at a Table by Jan Davidst de Heem 1628. There are no know pictures of Isaac Beeckman

Isaac Beeckman was born, the son of Abraham Beeckman a candle maker, in Middelburg in Zeeland in 1588. His father was Counter-Remonstrant the strict orthodox wing of the Calvinist Church in the Dutch Republic and Isaac adhered to this theological stand point all of his life. Isaac went to the University of Leiden in 1607 but before he went he spent three months studying mathematics with Jan van den Broecke a distant relative. His course of studies in Leiden was the liberal arts and theology but he went to Rudolph Snel van Royan (Rudolph Snellius), the father of Willebrord Snel and an important figure in the early history of science in the Dutch Republic, and asked him to recommend books for a course of self-study in mathematics. He pursued this course of study so intensely that he suffered a minor breakdown. However, he recommenced his studies and left the university in 1610.

Back in Middelburg he went to work for his father and within a year he qualified as a master candle maker and set up his own company. Leaving the candle making to his foreman he devoted his energies to working as a hydro-engineer. In those years he travelled much and also studied much. In 1618 after two years of self-instruction he took his master’s degree in medicine at the University of Caen. In 1619 he became vice rector of a school run by one of his brothers. Later he would go on to become rector of his own school and schoolmaster remained his profession until his relatively early death in 1637, only 49 years old.

From his early days as a student Beeckman was a passionate natural philosopher and he wrote down his thoughts, speculations, theories, experiments and deductions in what he called his ideas book and which is now known as his Journal. Very early he rejected the dominant Aristotelian world-view and developed his own version of an atomist philosophy including the acceptance of a vacuum surrounding his atoms. He also developed a mechanistic philosophy of motion. This requires physical contact between objects for changes in motion. However Beeckman also took the step of rejecting rest as the natural state and developed a theory of inertia. In opposition to Galileo, whose theory he didn’t know at the time, Beeckman’s theory of inertia sees natural motion as linear and not circular. He also so accepted circular inertial motion but aware that objects on a rotating disc shoot off at a tangent thought that circular inertial motion would almost never be observed in normal circumstances.

In 1618 Beeckman met and got to know the young René Descartes in Breda in Holland. Descartes was much impressed with the Dutch amateur natural philosopher and eagerly read and absorbed the idea book. During their time together Beeckman explained to Descartes his physical theory of fall and Descartes correctly derived the mathematical laws of fall from it; he was a much better mathematician than Beeckman. This was of course well before Galileo published his own derivation. Curiously Descartes would later reject his own derivation because it was dependent on the acceptance of a vacuum, which he rejected.

Later Beeckman came into contact with Pierre Gassendi and Marin Mersenne who both visited the philosophical schoolmaster and read with interest the idea book. Both of them kept in touch by letter on their return to Paris.

Beeckman’s influence on Descartes and his later philosophy was substantial, although Descartes later denied it when he became famous and over the years Descartes scholars have tried to sweep it under the carpet. Beeckman, who produced the first mathematical law of music, corresponded fairly extensively with Mersenne on the subject, an area of interest that both men shared and he certainly influenced Mersenne’s work on the subject. Gassendi is credited with having made atomism acceptable to the Church, the Greek theory being tainted with its association with atheism. He did so after first becoming aware of Beeckman’s atomism a theory developed by a deeply religious Calvinist.

Beeckman’s Journal was never published in the seventeenth century and was for a long time thought lost until it turned up at the end of the nineteenth century. As a result and because of Descartes very nasty dismissal of his work he became a forgotten figure until Cornelis de Waard published the Journal in the twentieth century. Research, since that publication, has shown that Beeckman was an important and influential figure in the evolution of modern science in the seventeenth century.

An important aspect of the Beeckman story for the history of science lies in the fact that he published nothing during his own lifetime. Historians have a strong tendency to orientate themselves on published books and develop a cannon of the important books that delineate the evolution of science. Beeckman’s life story, however, shows that personal contact, private conversations and correspondence can play just as big a role if not an even bigger one in that evolution.

Klaas van Berkel’s book on Beeckman’s life and work is excellent and goes into much more detail than I can in a brief blog post. As well as the main text it has very extensive endnotes with many recommendations for further literature on every single topic dealt with in the main text. I would recommend it to anybody who is really interested in the history of the evolution of modern science in the seventeenth century.

[1] Klaas van Berkel, Isaac Beeckman on Mater and Motion: Mechanical Philosophy in the Making, The Johns Hopkins University Press, Philadelphia, 2013.

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Really! – Did the artist have a Tardis?

Those who read the occasional bursts of autobiographical information that appear here on the blog might be aware that I went to university at the tender age of eighteen as an archaeology student. I actually dropped out after one year but continued to work as a professional field archaeologist (that’s a digger to you mate) for several years. Given that I was already interested in the history of astronomy in those days and would eventually abandon archaeology for it, it would seem logical that I would be interested in archaeoastronomy, in particular because I studied under Richard Atkinson who together with Stuart Piggott carried out the first extensive, modern excavation of Stonehenge, the world’s most famous archaeoastronomical monument, in the 1950s. In fact my father also worked on that excavation. This assumption would be correct with reservations. There has been some excellent work in archaeoastronomy but unfortunately there has also been a large amount of highly dubious speculation on the topic.

In my opinion an example of the latter appeared in articles in The Guardian and on the Hyperallergic website a couple of days ago. The Guardian article was entitled, Two suns? No, it’s a supernova drawn 6,000 years ago, say scientists. This article tells us:

For decades, stone carvings unearthed in the Himalayan territory of Kashmir were thought to depict a hunting scene. But the presence of two celestial objects in the drawings has piqued the interest of a group of Indian astronomers.

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Source: The Guardian

They have proposed another theory. According to a study published in the Indian Journal of History of Science, the Kashmir rock drawings may be the oldest depiction of a supernova, the final explosion of a dying star, ever discovered.

 “Our first argument was, there cannot be two suns,” Vahia said. “We thought it must have been an object that appeared and attracted the attention of the artists.”

 They settled on Supernova HB9, a star that exploded around 4,600BC.

Rewinding the map of the sky back that far revealed more clues.

Viewed from Kashmir, the supernova would have occurred somewhere near the Orion constellation. “Which is known as the scene of a hunter,” said Vahia.

“The supernova also went off just above the constellation of Taurus, the bull, which is also seen in the drawing,” Vahia added.

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Source: The Guardian

So to summarise a group of astrophysicists decide that the rock drawing depicts a supernova from around 4,600 BCE that was visible in the sky in the area of the constellations Orion the hunter and Taurus the bull, which according to the researchers are also depicted in the drawing. It is by the latter claim that my bullshit detectors went off at full volume. I will explain.

The chosen supernova occurred in 4600 BCE, now I’m not an expert on prehistoric Indian asterisms, I don’t even know anybody who is, but I do know something about the Babylonian and ancient Greek ones. Taurus is indeed one of the oldest known asterisms but the earliest known mention of a bull asterism is in the Sumerian record, the Heaven’s Bull, in the third millennium BCE, that’s a couple of thousand years after the chosen supernova. Even worse it is not known whether the Sumerian asterism is the same one as the later Babylonian/Greek asterism Taurus. With Orion we have even more problems. The Sumerian asterism involving the stars of Orion was a sheep. For the ancient Egyptians the stars depicted their god Osiris. It was first the Greeks who created the asterism Orion although some mythologists see Orion as a representation of the Sumerian King Gilgamesh, who also fought a bull. This is of course highly speculative.

So we have astrophysicists identifying a rock drawing in India that is dated to the fifth millennium BCE with the constellations of Orion fighting Taurus, asterisms which don’t appear to have been identified till several thousand years later. Excuse me if I am somewhat sceptical about this identification. Just as a minor point I don’t think that the animal in the drawing actually looks like a bull, more like a stag in my opinion.

 

 

 

 

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Andromeda – From nebula to galaxy

The word galaxy derives from the Greek word galaxias meaning milky one, which was the ancient Greek term for the Milky Way that indistinct band of stars visible across the night sky in areas that don’t suffer from too much light pollution. Today galaxy is used as the general term for the very large groups of stars scattered around the universe. Current estimates of the total number of galaxies range from 2×1011 to 2×1012 or even more. Confronted by these vast numbers it is oft easy to forget that less than one hundred years ago we still thought that our galaxy, the Milky Way Galaxy, was the entire universe. This changed on 1 January 1925 when H.N. Russell read a paper by Edwin Hubble to the American Association for the Advancement of Science, which established that spiral nebulae were in fact separate galaxies. The path through the history of astronomy leading up to that epoch defining paper in 1925 goes back almost one thousand years and in what follows I shall briefly outline some of the important stations, nearly all of which concern our nearest galactic neighbour Andromeda, along that path.

The word nebula comes from the Latin and means a cloud, mist, fog, smoke, vapour, exhalation, as you can see the definition is fairly nebulous. In astronomy it can be traced back to Ptolemaeus’ Mathēmatikē Syntaxis or as it is more commonly known The Almagest. In this founding work of Western astronomy Ptolemaeus lists a total of six astronomical nebulae without giving them any great attention. All of Ptolemaeus’ nebulae were in fact indistinct star clusters too far away to be resolved with the naked eye. The first so-to-speak true nebula, the Andromeda nebula, was recorded by the Persian astronomer Abd al-Rahman al-Sufi, usually just referred to as Al Sufi, in his Book of Fixed Stars (Arabic: kitab suwar al-kawakib) around 964 CE. He describes and illustrated the Andromeda nebula as a little cloud before the mouth of the Arabic constellation Fish.

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Al Sufi’s drawing of the constellation Fish with the Andromeda nebula in fount of it mouth

Amongst his other early telescopic observations Galileo showed that the Ptolemaic nebulae resolved into many unseen stars when viewed through the telescope. In 1612, it was, however, Galileo’s telescopic rival, Simon Marius who first turned his telescope on the Andromeda nebula and saw that it didn’t resolve into stars when viewed through his telescopic lenses. In his Mundus Iovialis (1614) Marius described what he saw as follows:

Among them the first is that with the spy-glass, from 15 December 1612 I discovered and observed a fixed star with a certain wonderful shape that I cannot find in the entire heavens. It is near the third and northernmost [star] in the belt of Andromeda. Without the instrument the same is seen as some sort of little cloud; and with the instrument no distinct stars are seen as in the nebular star in Cancer and other nebular stars, but rather only white rays, which the closer to the centre the brighter they come out; in the centre there is a dull and pale light; and its diameter is about a quarter of a degree. About the same brilliance appears when a bright candle is observed through a clear lantern from a long distance.

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Simon Marius from the frontispiece of the Mundus Iovialis Source: Wikimedia Commons

The research into nebulae came of age first in the eighteenth century with the work of the French comet hunter Charles Messier (1730–1817). In order to make it easier for comet hunters to distinguish potential comet sightings from other indistinct and nebulous object in the night sky, Messier began to compile a catalogue of the positions and appearance of all such objects that he detected during his nightly vigils. His work, the final version of which was published in 1781 and is now known as the Messier Catalogue, contains a list of 110 Messier objects, in his time nebulae and star clusters. The Messier objects are now known to be 39 galaxies, 5 planetary nebulae, 7 other types of nebulae and 55 star clusters. The Andromeda nebula, the discovery of which Messier, ignorant of Al Sufi’s book, falsely attributes to Marius, is Messier object M31.

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Charles Messier, French astronomer, at the age of 40 Source: Wikimedia Commons

Although Messier’s catalogue was compiled to assist comet hunters in differentiating potential comets from other faint celestial objects it is usually regarded as an early example of so-called deep sky astronomy; that is the study of objects well outside the solar system. The man who first practiced deep sky astronomy systematically was William Herschel, who together with his sister Caroline, methodically map the heavens quadrant for quadrant recording with his 20 foot reflecting telescope all of the non-stellar objects he could find. Caroline and he recorded 2400 nebulae in three catalogues.

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William and Caroline Herschel polishing a telescope lens, 1896 Lithograph. Source: Wellcome Collection via Wikimedia Commons

They categorised the objects that they recorded into eight classes: (I) bright nebulae, (II) faint nebulae, (III) very faint nebulae, (IV) planetary nebulae, (V) very large nebulae, (VI) very compressed and rich clusters of stars, (VII) compressed clusters of small and large [faint and bright] stars and (VIII) coarsely scattered clusters of stars. Extended by his son and later John Dreyer, Herschel’s catalogue became the New General Catalogue (NGC) of 7840 deep sky objects in 1888. The NGC numbering is still used for most of the objects recorded therein. In 1785 Herschel observed a faint reddish hue in the core region of Andromeda. He believed Andromeda to be the nearest of all the great nebula.

In 1750 the English astronomer Thomas Wright (1711–1786) published his An Original Theory on New Hypothesis of the Universe in which he was the first to correctly describe the shape of the Milky Way Galaxy. He also speculated that the faint nebulae where in fact distant galaxies. However, his very perceptive thoughts remained speculations that he was unable to verify.

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Thomas Wright in 1737 Source: Wikimedia Commons

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Illustration of groups of stars, from An original theory or new hypothesis of the Universe, plate XVII Source: Wikimedia Commons

Interestingly his speculations were taken up by the German philosopher Immanuel Kant (1724–1804) and further developed in his anonymously published Allgemeine Naturgeschichte und Theorie des Himmels (Universal Natural History and Theory of Heaven) (1755). At the time neither Wright’s nor Kant’s theories received much credence but with hindsight both have been praised for their perceptiveness.

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Title page of Kant’s Allgemeine Naturgeschichte und Theorie des Himmels Source: Wikimedia Commons

In 1850, William Parsons, using the largest reflecting telescope constructed in the nineteenth century the Leviathan of Parsonstown, was able to identify the spiral structure of the Andromeda nebula for the first time. This was just one of a series of spiral nebula, in reality galaxies, that he was able to identify.

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The largest telescope of the 19th century, the Leviathan of Parsonstown. Source: Wikimedia Commons

In 1864 William Huggins, a pioneer in stellar spectroscopy, noted that the spectrum of Andromeda differs from that of a gaseous nebula. The spectrum, as observed by Huggins, had the same characteristics as the spectrum of individual stars leading he to conclude that Andromeda was in fact stellar in nature.

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Sir William Huggins, by John Collier Source: Wikimedia Commons

We have already come a long way from Al Sufi’s first record of a small cloud. In 1887, Isaac Roberts, who thought that spiral nebula were solar systems in the process of forming, took the first-ever photograph of Andromeda.

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Isaac Roberts’ picture of the Great Nebula in Andromeda Source: Wikimedia Commons

In 1912 the American astronomer, Vesto Slipher, measured the rotational velocity of Andromeda using spectroscopy at 300kilometres per second the highest yet measured velocity.

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V.M. Slipher, astronomer at Lowell Observatory from 1901 to 1954. Source: Wikimedia Commons

In 1917 Heber Curtis observed a nova in Andromeda and discovered eleven more in the photographic record. These were on average ten magnitudes weaker that others observed in the heavens. Based in this data he estimated that Andromeda was 500,000 light-years distant. Curtis now proposed the island universes hypothesis i.e. spiral nebulae are actually independent galaxies.

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Heber Doust Curtis poses before the Crossley telescope. Source: Wikimedia Commons

On 26 April 1920 Heber Curtis and Harlow Shapley held the so-called great debate at the Smithsonian Museum of Natural History on the nature of spiral nebulae. Curtis argued that they were distant independent galaxies, Shapley that they were much smaller and much nearly and thus within the Milky Way galaxy, which was the entire universe. This debate raised the question to the priority question in astronomy.

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Portrait of Harlow Shapely Source: Wikimedia Commons

In 1922 Ernst Öpik measured the distance of Andromeda using the velocity of stars. His estimate was 1,500,00 light-years.

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Ernst Julius Öpik Source: Wikimedia Commons

As I said in the opening paragraph Edwin Hubble finally settled the mater when he measured the distance of Andromeda using Cepheid variable stars and proved conclusively that Andromeda was not a nebula inside the Milky Way but a separate galaxy. With this result the age of galactic astronomy was born.

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Studio Portrait of Edwin Powell Hubble. Photographer: Johan Hagemeyer Source: Wikimedia Commons

Of interest the method of determining distances using Cepheids was developed by Henrietta Swan Leavitt, one of the Harvard computers, investigating thousands of variable stars in the Magellanic Clouds in 1908; she published her results in 1912.

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Henrietta Swan Leavitt working at her desk in the Harvard College Observatory Source: Wikimedia Commons

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Early photograph of ‘Pickering’s Harem’, as the group of women assembled by Harvard astronomer Edward Charles Pickering, who were dubbed as his “computers”. The group included Leavitt, Annie Jump Cannon, Williamina Fleming, and Antonia Maury. Source: Wikimedia Commons

The story of Andromeda’s historical journey from Al Sufi’s nebula to Curtis’ galaxy illustrates very nicely how scientific knowledge grows over time with generations of researchers with differing interests and motivations contributing directly and indirectly to that growth.

Post amended 11 January 2018

 

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