Astronomical Research in the Time of Galileo Galilei

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1 • Galileo, the Church, and Astronomy…

When it comes to Galileo Galilei, most people retain a rather faded memory from high school about the issue…

galileo galilei cliche

Everyone remembers the main facts, though:

  • The Church hindered scientific research.
  • Galileo, on the other hand, being an individual outside the mainstream, conducted his research in secret, within a hostile environment.
  • After the Inquisition discovered his activities, Galileo was arrested, tortured, and sentenced to death.

…too bad that none of these three statements are true!

…

Since Galileo’s story is a bit complex, I revisited two specific pages:

Today, however, I would like to focus on the historical and scientific context… namely:

  • How was astronomical research going in Galileo’s time?
  • Did the ecclesiastical hierarchy oppose science?
  • Did it consider it something dangerous? Something incompatible with the Catholic faith?

2 • Cardinals Observing the Sky…

Contrary to what is believed, during Galileo’s time, astronomical research was in great turmoil.

Even (or perhaps especially?) within the Catholic sphere.

A silly example: already 100 years before Galileo’s birth, the German cardinal, mathematician, and astronomer Nicholas of Cusa (1401-1464) had started conducting very intriguing studies…

…with his “De docta ignorantia” (completed in 1440), he was among the first to hypothesize that the matter of celestial bodies could have the same composition as earthly matter; so much so that he did not rule out the existence of other living beings in space (cf. De docta ignorantia II, 12,171-172).

nicholas of cusa

Cusanus had also intuited (though unable to prove it mathematically) that the Earth was not at the center of the universe and that it moved:

The earth, which cannot be the center of the universe, cannot be without movement either […] Since it is not possible for the world to be enclosed between a bodily center and a circumference, it remains unknowable, since its center and circumference are God.

(NICCOLÒ CUSANO, De docta ignorantia II, 11,156)

Okay, Cusanus’s reasoning may be somewhat eccentric (the Earth would not be at the center of the universe because, if God is infinite, “the center” and “the circumference” should be occupied by Him)…

…but it’s interesting to note that almost 100 years before Copernicus, a German cardinal was already questioning the position (and movements) of the Earth in the cosmos.

3 • Nicolaus Copernicus, Astronomer and Mathematician, Priest and Canon

The first to propose heliocentrism in the modern era was Nicolaus Copernicus (1473-1543), a Polish astronomer and mathematician, as well as a Catholic priest (Wikipedia informs that he also had a degree in canon law).

Copernicus conducted his research in Frauenburg (in present-day Poland).

He was a member of the chapter of Warmia, as well as a canon (*)…

nicolaus copernicus

…thanks to this ecclesiastical position, he received a stipend, with which he pursued his research (even Galileo Galilei held the role of canon, in 1631, at the cathedral chapter of Pisa) (cf. F. MARCACCI – W.R. SHEA, Intervista a Galileo, Carocci, Roma 2015, p. 53).

4 • Nicolaus Copernicus and Heliocentrism

Copernicus’s most important work was “De revolutionibus orbium coelestium” (published in 1543, the year of his death), in which the astronomer theorized a planetary model where the sun was “placed at the center,” and the other planets revolved around it.

Here are some lines from Copernicus’s introduction to his work:

Since it is the nature of all good arts to remove from the mind of man the vice and to lead it to better occupations, this one [astronomy], in addition to the incredible intellectual pleasure it provides, can achieve this effect more fully. For who, applying himself to those things that, arranged in perfect order, he sees directed by divine governance, would not be called to perfection by their continuous contemplation and a certain familiarity, and would not admire the artisan of all in whom every happiness and all good are placed? Indeed, the divine psalmist would say in vain that he rejoiced in the creation of God and exulted in the work of His hands if these means did not lead us, like a vehicle, to the contemplation of the highest good.

(available in NICCOLÒ COPERNICO, La struttura del cosmo, translated by R. GIROLDINI, Olschki, Firenze 2009, p. 20)

In just a few lines, Copernicus says that:

  • natural phenomena are moved “by divine governance”;
  • those who contemplate the order of the laws of the cosmos can perceive – through them – the Artisan who wrote them;
  • the psalmist David (*) did well to rejoice “in the creation” because wonder at it leads us “to the contemplation of the highest good” (i.e., God).

(*) Note for Muggles: This is a reference to Psalm 19, traditionally attributed to David, the famous king of Israel…

The heavens declare the glory of God;
And the firmament shows His handiwork.
Day unto day utters speech,
And night unto night reveals knowledge.
There is no speech nor language
Where their voice is not heard.
Their line has gone out through all the earth,
And their words to the end of the world.

(Psalm 19:1-4)

atheist scientists

The “De revolutionibus […]” was preceded by a letter in which Copernicus dedicated his investigation to Pope Paul III, expressing hope that his study would bring “some advantage” to the Church:

Mathematics is written for mathematicians, to whom, if I am not mistaken, this work of mine will appear to bring some advantage even to the state of the Church, whose principality is now held by Your Holiness.

(NICCOLÒ COPERNICUS, La struttura del cosmo, translated by R. Giroldini, Olschki, Firenze 2009, p. 17)

However, in Copernicus’ investigation, there was a lack of proof for the movement of the Earth (*); Copernicus did not have the tools to calculate the ratio of the distance between the Earth and the Sun, nor a series of other pieces of information to demonstrate the truth of the heliocentric model…

(*) (evidence that – as we will see next week – Galileo also lacked)

In addition to this shortcoming, there were also some errors: in his model, the scientist spoke of circular orbits of the planets (and not elliptical); furthermore, he hypothesized the presence of epicycles and eccentrics in the trajectory of the orbits.

In short, Copernicus tried to make the accounts work…

make the accounts work

5 • Celio Calcagnini (who – poor thing – nobody knows)

Celio Calcagnini (1479-1541) was a humanist and diplomat of the Duchy of Ferrara… as well as a Catholic priest, canon, and apostolic protonotary.

Around 1520, he wrote a pamphlet (with the somewhat lengthy title: “Quod caelum stet, Terra moveatur vel de perenni motu Terrae”) containing his astronomical considerations in light of the dialogues he had with Cardinal Ippolito d’Este (also interested in astronomy).

In the work (among many things), Celio argues that:

  • the earth rotates on its axis;
  • the celestial vault does not revolve around it; indeed, according to his observations, to revolve around the earth, the celestial vault would have had to have a too high velocity…

Yes, okay, the term “too high” is not very scientific…

celio calcagnini

In summary, the discourse was based more on personal impressions than on astronomical observations…

… However, it is not trivial that:

  • in addition to the “famous” Copernicus and Galileo, there were many others interested in astronomy…
  • … many of these individuals delving into the
    world of science were priests.
  • Calcagnini, in his speculations, comfortably engaged with a prominent figure in the ecclesiastical hierarchy like Ippolito d’Este – defying the fanciful “obscurantism” or “climate of fear” purported by the Inquisition…

Conclusion – So what about Galileo?

If everything I have written is true (and it is), why did the Inquisition condemn Galileo?

The issue was certainly not “scientific” (as you might have gathered from the paragraphs above, filled with priests, astronomers, cardinals, and apostolic protonotaries observing the sky, and so on…).

The Church endorsed science, observations on the movement of planets, their rotation around the Sun or their own axes, and so forth…

… the problem with Galileo was not “scientific” but “theological” (or, more precisely, “exegetical”).

In what sense?

Let’s not delve too deeply into this… As mentioned above, if you want to explore the “Galileo issue,” I have dedicated two specific pages to it:

Best regards,

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(Winter 2020-2021)

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