As a history of science blogger, whose reputation is built to a large extent on my playing Whac-A-Mole with crappy pieces of history of science, I should be eternally grateful for Galileo, the gift that keeps on giving. Actually Galileo is not the problem, it is the people who choose to write about him. What is most frustrating is that there is a vast amount of accessible literature written by historians of science that the offenders could consult to get their pieces about Galileo correct but they don’t seem to think that they need to do so. So who is the latest offender? Alan Lightman has published an essay in the online journal Nautilus with the title, When the Heavens Stopped Being Perfect: The advent of the telescope punctured our ideals about the nighttime sky. In fact it’s a part of his newly published book, Searching for Stars on an Island in Maine.
Alan Lightman is according to his Wikipedia page an ex astrophysicist turned novelist, who has published an impressively long list of both fact and fiction books. He also has an almost as long list of honorary doctorates. One could expect that such an author would know how to consult historical sources, primary and or secondary, and thus get his facts right, apparently not!
In his essay Lightman wishes to pay tribute to Galileo’s first major publication the Sidereus Nuncius, which is in and of itself a good thing as it is to quote Lightman, “one of the most consequential volumes of science ever published.” So far so good.
Title page of Sidereus nuncius, 1610, by Galileo Galilei Source: Wikimedia Commons
In his introductory biographical sketch Lightman write:
Unable to discharge his financial responsibilities on his academic salary alone—he had to pay the dowries of his sisters in addition to supporting his three children by a mistress—he took in boarders and sold scientific instruments.
As head of the family following the death of his father, he did indeed have to pay the dowries for his sisters a financial burden that he could have lived without. However, Galileo was also a bon vivant, who almost certainly lived beyond his means, so his financial problems were certainly aggravated by his life style. Taking in the student sons of rich families as boarders was a common practice amongst Renaissance university professors, as it provided a nice extra income and good connections to the influential parents. This is something Galileo would probably have done with or without financial problems and not something he was forced to do. The same applies to his instrument making. Designing, making and selling mathematical instruments was again a very common practice amongst Renaissance professors of mathematics and medicine and something in which Galileo excelled, so once again voluntary and not a burden. We now arrive at the telescope:
In 1609, at the age of 45, he heard about a new magnifying device just invented in the Netherlands. Without ever seeing that marvel, he quickly designed and built a telescope himself, several times more powerful than the Dutch model. He seems to have been the first human being to point such a thing at the night sky. (The telescopes in Holland were called “spyglasses,” leading one to speculate on their uses.)
The story that Galileo built his first telescope purely by here say, without having seen one, a claim which he set in the world, has been largely debunked. He almost certainly saw one through the offices of Paolo Sarpi, who first drew his attention to the instrument. Also Galileo took surprisingly long between first hearing of the telescope and actually building one. Eileen Reeves thinks that before he actually saw one he thought it had something to do with mirrors rather than lenses and thus lost time on a wild goose chase. He was definitively not the first person to point one at the night sky, as I have written on a number of occasions. To quote myself:
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.
Galileo ground and polished his own lenses. His first instruments magnified objects a dozen or so times. He was eventually able to build telescopes that magnified a thousand times and made objects appear 30 times closer than they actually were.
Remember those instruments? Galileo employed a full time instrument maker, although he did work in the workshop himself. I mention this because his instrument maker, Marc’Antonio Mazzoleni rarely gets the credit he deserves. Galileo’s first instruments, such as the one he demonstrated to the Senate of Padua, magnified nine times. His later observational instruments varied between twenty and thirty times magnifications. The problem with Dutch or Galilean telescopes is the higher the magnification the smaller the field of view, anything above thirty is practically useless. A Galilean telescope, which magnified a thousand times is pure fantasy! That would really have been a sensation! Lightman, an astrophysicist remember, here falls into a trap that Galileo laid out for the careless reader. If a telescope magnifies the sides of a square thirty times then it magnifies the area of the square thirty times thirty, equals nine hundred or approximately one thousand!
Lightman now indulges in a bit of fairy tale telling:
Many people were skeptical, questioning the legitimacy of the device and thus the validity of its findings. Some regarded the strange tube as magical, not of this world, as if a cell phone were presented to someone in the year 1800. Galileo himself, although a scientist, did not understand exactly how the thing worked.
We should recall that belief in magic, sorcery, and witchcraft was widespread in Europe in the 16th and 17th centuries. In just those two centuries, 40,000 suspected witches, most of them women, were burned at the stake, hung from the gallows, or forced to put their heads on the chopping block. In 1597, King James VI of Scotland (who in 1603 became James I of England) complained about the “fearefull abounding at this time [and] in this Countrey, of these detestable slaves of the Divel, the Witches or enchaunters.” It was believed that sorcerers could cast spells by damaging a strand of hair or a fingernail of an intended victim. Was the Italian mathematician’s device a bit of sorcery?
I have read a vast amount of literature about the early use of the telescope both by Galileo and by all of the other early users. I have read all of the objections, the discussions, the rejections and the acceptances but not once have I ever come across a reference that people thought the telescope or the observations made with it were magic or sorcery. Lightman seems to have extracted this little piece of ridiculousness out of his…
Within a couple of months of the publication of Sidereus Nuncius, Galileo became famous throughout Europe—in part because the telescope had military and commercial value as well as scientific. (From “the highest bell towers of Venice,” Galileo wrote to a friend, you can “observe sea sails and vessels so far away that, coming under full sail to port, 2 hours and more were required before they could be seen without my spyglass.”) Word of the invention traveled by letter and mouth.
Maybe I’m not reading this paragraph correctly but as I read it Lightman is saying that the spread of news of the telescope was due to Galileo’s publication. This is rubbish, the news of the new invention spread like wildfire after the first demonstration in The Hague in September 1608. This was largely due to the 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. However it was also due to the fact that Maurits van Nassau sent telescopes as gifts to many of the crowned heads of Europe including the Pope. For example, the Jesuit astronomers of the Collegio Romano were already making telescopic astronomical observations well before Galileo published his Sidereus Nuncius. It was this widespread knowledge of the telescope that first led Galileo, in far away Padua, to hear of the telescope.
In his book, Galileo exhibits his own pen-and-ink drawings of the moon seen through his telescope, showing dark and light areas, valleys and hills, craters, ridges, mountains. He even estimates the height of the lunar mountains by the length of their shadows.
The illustrations of the Moon are not pen-and ink drawings but washes, i.e. monochrome watercolour paintings.
All of which supported the proposal of Copernicus, 67 years earlier, that the sun, rather than the earth, is the center of the planetary system. These were quite a few new ideas to pack into such a little book. And with no apologies to Aristotle or the Church.
Altogether now in chorus, the telescopic discoveries published in the Sidereus Nuncius neither refute the Ptolemaic geocentric astronomy nor do they support the Copernican heliocentric astronomy. They merely shred the Aristotelian cosmology.
All of it supposedly constructed out of aether, Aristotle’s fifth element, unblemished and perfect in substance and form, what Milton described in Paradise Lost as the “ethereal quintessence of Heaven.” And all of it at one with the divine sensorium of God. What Galileo actually saw through his little tube were craters on the moon and dark acne on the sun.
Lightman doesn’t seem to be aware that the discovery of the sunspots cannot be found in the Sidereus Nuncius, they came later.
Galileo’s announcement of dark spots on the sun was an even greater challenge to the divine perfection of the heavens. We now know that “sunspots” are caused by temporary concentrations of magnetic energy in the outer layers of the sun. Being temporary, sunspots come and go. In 1611, Christoph Scheiner, a leading Jesuit mathematician in Swabia (southwest Germany), procured one of the new gadgets himself and confirmed Galileo’s sightings of moving dark spots in front of the sun. However, Scheiner began with the unquestioned Aristotelian premise that the sun was perfect and unblemished, and he went from there to proposing various precarious arguments as to why the phenomenon was caused by other planets or moons orbiting the sun rather than the sun itself.
Note, Galileo constructed his own telescope, whereas according to Lightman Christoph Scheiner merely “procured one of the new gadgets.” Actually Scheiner like Galileo constructed his own telescope and was in fact very good at it. Scheiner did not confirm Galileo’s sightings of moving dark spots in front of the sun. When Marcus Welser published Scheiner’s Three Letters on Sunspots, Galileo had not published anything on the subject and was caught, so to speak, with his pants down. This of course explains his violent reaction, somebody was poaching on his territory, he, and he alone, was the great telescopic discoverer of marvels in the heavens. Of course both Scheiner and Galileo were blissfully unaware that Thomas Harriot had made the discovery before either of them or that Johannes Fabricius had already published a booklet on the subject. Scheiner did indeed initial suggest that the sunspots were the shadows of satellites orbiting the sun. This actually spurred Galileo on to prove that they were really on the surface of the sun, something he had not done before being goaded by Scheiner. Scheiner accepted Galileo’s proof with grace and then went on to devote several years to intensive solar astronomy producing much new information.
When Galileo’s observations became known, churchmen reacted with skepticism. On March 19, 1611, Cardinal Robert Bellarmine, head of the Collegio Romano, wrote to his fellow Jesuit mathematicians:
I know that your Reverences have heard about the new astronomical observations by an eminent mathematician … This I wish to know because I hear different opinions, and you Reverend Fathers, being skilled in the mathematical sciences, can easily tell me if these new discoveries are well founded, or if they are apparent and not real.
Although the Church mathematicians argued about the details of Galileo’s findings, they unanimously agreed that the sightings were real. Nevertheless, Galileo’s telescopic findings and his support of the heliocentric model of Copernicus were considered an unpardonable attack on theological belief. For that offense, Galileo, a pious Roman Catholic who had once seriously considered the priesthood, was eventually tried by the Inquisition, forced to recant most of his astronomical claims, and spent the later years of his life under house arrest.
The astronomers of the Collegio Romano had begun their efforts to confirm Galileo’s discoveries, with Galileo’s active assistance, well before Bellarmine asked their opinion on the matter. Almost everybody was of course sceptical of Galileo’s quite extraordinary claims. They, after some effort, confirmed the findings and held a banquet in Galileo’s honour to celebrate the discoveries. Galileo’s telescopic findings played absolutely no role in his trouble with the Inquisition or his subsequent trial.
I want to focus now not on the displacement of earth as the center of the cosmos but on the newly conceived materiality of the heavens. Because it was that materiality, that humbling of the so-called heavenly bodies, that struck at the absolute nature of the stars.
Here Lightman goes off on a long excurse evoking Kepler’s Somnium and Giordano Bruno amongst other on the materiality of the stars. He writes:
Once Galileo and others had declared the stars to be mere material, their millennia were numbered— because all material things are subject to the law of the conservation of energy.
Lightman wants his readers to believe that there was a direct link between the discovery of sunspots and the acceptance that the sun is just another star and that all stars are material. This is historically simple not true, Galileo never declared the stars to be mere material and it took quite a long time for this chain of thought to establish itself in the world of astronomy. If I were a university teacher grading Lightman’s essay in an introductory history of astronomy course, I would give it a big fat F.