Old Hulky[2] was thinking of taking time off for the summer and retiring to an ice floe[3] in the North Atlantic for a couple of weeks to escape the heat wave, when Neil deGrasse Tyson has to go and publish a piece of history of astronomy inanity that would have to look hard to find its equal and now he’s on the rampage–stomp, stomp, stomp…
If you know anything about the history of astronomy read the following and weep:
‘For thousands of years, humans reasonably assumed the Moon to be a flat disk of light that waxed and waned – until the 17th century, when Galileo dared turn his freshly perfected telescope skyward, revealing a textured sphere with jagged mountains drenched in sunlight and sloping valleys cloaked in shadow. From that moment onward, the heavens and all the celestial objects therein became worlds…’ [4]
Hulky thinks that NdGT must be a male of the species Bos taurus because he can pack so much bovine manure into just one paragraph of sixty-four words!
For thousands of years, humans reasonably assumed the Moon to be a flat disk of light that waxed and waned – until the 17th century…
Hulky: I think he’s just making shit up!
I’m afraid I have to agree with my combative friend. I have spent half a lifetime studying and researching the European history of astronomy and have never come across a theory about the Moon from anybody that even halfway resembles the piece of ahistorical verbal garbage that NdGT spews out in the sentence above. Let us briefly look at the lunar theories held and developed by the Ancient Greeks that were dominant in European thought up to the Early Modern Period.
Starting with the Pre-Socratics, apparently Anaximander really did think that the Moon was a flat disc but both Thales and Parmenides claimed it was a sphere. Anaxagoras thought that both the Sun and the Moon were big stones, and that moonlight was in fact reflected sunlight. However, as I have stated in the past I view claims about the beliefs of the Pre-Socratics, which are based on hearsay often hundreds of years after they lived, very sceptically, so I’ll turn to more reliable sources. For Aristotle, all seven planets (asteres planētai, wandering stars)–Moon, Mercury, Venus, Sun, Mars, Jupiter, Saturn–were perfect unblemished spheres, made of aether, the fifth element or quintessence. Generally, in Aristotelian cosmology, which dominated thought in Europe from the twelfth down to the seventeenth century, the Moon is illuminated with Sun light, a model that is used to explain both the phases of the Moon and eclipses. Although there existed a debate as to whether the Moon had its own light.
Maybe, NdGT doesn’t like philosophers and prefers astronomers. In his Mathēmatikē Syntaxis, written around 150 CE, Ptolemaeus, whose astronomy dominated in Europe, again from the twelfth down to the seventeenth century, we can read the following in Book IV:
For the distance between the sphere [my emphasis] of the moon and the centre of the earth…[5]
Or Book V
The ratios of the volumes of the bodies are immediately derivable from the ratios of the diameters of sun, moon and earth.[6]
Both quotes leave no doubt that for Ptolemaeus the Moon was a sphere.
…when Galileo dared turn his freshly perfected telescope skyward…
When I was young there was a widely spread myth that Galileo invented the telescope. It has in the meantime largely disappeared, although it still crops up from time to time. It would appear that it has been replaced with the equally mythical claim that Galileo perfected the telescope. This is the second time that NdGT has recently made this claim.
Hulky: He obviously believes that if you repeat a myth often enough then the suckers will believe it
Galileo succeeded in raising the magnification of the telescope originally launched by Hans Lipperhey in Middelburg in 1608, as did Thomas Harriot, Simon Marius, and Antonio Santini, and later many others but to talk of a perfected telescope is a joke. The early telescope lenses were made of very poor-quality glass and the grinding and polishing of those lenses left much to be desired. Suffering from both spherical and chromatic aberration, the images the early telescopes produced were blurred and had coloured fringes. As a result, there were lots of false sightings reported in the seventeenth century. That anybody was actually able to make accurate observations with those very poor-quality telescopes borders on a miracle.
…revealing a textured sphere with jagged mountains drenched in sunlight and sloping valleys cloaked in shadow.
Hulky: fancies himself as a bleeding poet, don’t he?
Probably due to his training as an artist, Galileo was able to interpret the dark patches he could observe on the Moon as shadows cast by uplands.
From that moment onward, the heavens and all the celestial objects therein became worlds…’
As I have pointed out on more than one occasion, Galileo’s hypothesis that the Moon’s surface was not perfectly smooth as Aristotle’s cosmology required but was Earth like with mountains and valleys was not as new or as spectacular as it is mostly presented.
That the moon was Earth like and for some that the well-known markings on the Moon, the man in the moon etc., are in fact a mountainous landscape was a view held by various in antiquity, such as Thales, Orpheus, Anaxagoras, Democritus, Pythagoras, Philolaus, Plutarch and Lucian. In particular Plutarch (c. 46–c. 120 CE) in his On the Face of the Moon in his Moralia, having dismissed other theories including Aristotle’s wrote:
Just as our earth contains gulfs that are deep and extensive, one here pouring in towards us through the Pillars of Herakles and outside the Caspian and the Red Sea with its gulfs, so those features are depths and hollows of the Moon. The largest of them is called “Hecate’s Recess,” where the souls suffer and extract penalties for whatever they have endured or committed after having already become spirits; and the two long ones are called “the Gates,” for through them pass the souls now to the side of the Moon that faces heaven and now back to the side that faces Earth. The side of the Moon towards heaven is named “Elysian plain,” the hither side, “House of counter-terrestrial Persephone.”[7]
Plutarch’s Moralia was a well-known, widely read, and much-loved text amongst Renaissance Humanists, so Galileo’s discovery was really not that sensational.
As, unfortunately, all too often NdGT is once again feeding his poor, benighted acolytes a diet of highly inaccurate, fanciful, ahistorical garbage. If I were National Geographic or their parent company Penguin Random House, I would be ashamed to have this detritus associated with my brand name.
[1] With apologies to Richard Rogers and Lorenz Hart
[2] Hulky is the Renaissance Mathematicus pet name for the HISTSCI_HULK
[3] Recommended to him by his friend Frankenstein’s much maligned monster as a good place to escape from the stress of civilisation.
[4] Neil deGrasse Tyson & Lindsey Nyx Walker, To Infinity and Beyond: A Journey of Cosmic Discovery, A StarTalk Book, National Geographic, NY, 2023, p. 17
[5] Ptolemy’s Almagest, Translated and Annotated by G. J. Toomer, Princeton University Press, ppb. 1998, p. 173
[6] Ptolemy’s Almagest p. 257
[7] The last two paragraphs are borrowed from my The emergence of Modern astronomy – a complex mosaic: Part XXI to save me having to rewrite it!