Week 25: Maculae Solares, Galileo Galilei feat. The Roman Inquisition, Simon Barraclough

Cover Image. Richard William Seale, “The Course of the Solar Maculae over the Sun’s Disk” (n.d.).

Waxing gibbous moon; summer solstice.

Headnote

A weather update from outer space:

We are more than halfway through Solar Cycle 25, which unexpectedly peaked in October 2024, about one year earlier than predicted. Scientists observed a maximum of 161 sunspots around this time, a number that also exceeded expectations and which led to a period of more-prominent space weather events, according to CBS 17 News. Summer 2026 may be subject to a so-called “double peak,” as the sun’s other hemisphere (north or south) takes its turn churning through spots, flares, coronal mass ejections, and other phenomena. But the forecast for the next few years is rather quieter, as we approach the end of the current cycle in around 2030.

Though normal human persons rarely notice it, the solar cycle influences the type and intensity of radiation surging toward our planet at any given moment. The cycle names an 11-year-long process during which the sun’s magnetic activity builds in complexity, until the whole star eventually reverses its polarity, with magnetic north and south changing places due to the swirling movements of immense quantities of burning plasma. It’s a wild mess up/over there. And yet so much hinges on the sun, spots and all.

Sunspots (maculae solares in Latin) were first observed in China nearly 3000 years ago, in the I Ching, preceding Theophrastus’ observations in Ancient Greece by several centuries. They were made infamous by Galileo Galilei in 1612, when he circulated a pamphlet challenging Aristotle’s view that the sun was an unblemished, immutable sphere. That offense was cited two decades later, when he was imprisoned by the Sacred Congregation of the Holy Roman and Universal Inquisition (not to be confused with the earlier Spanish Inquisition).* In theological and medical contexts, macula (meaning “spot” or “mark”) traditionally refers to either sin or the central retina, respectively. But the word has been used with various meanings over the past 600+ years and even may have lent a name to that spotted fish, the mackerel. Four centuries after the condemnation of Galileo’s heretical conclusions about sunspots, poet Simon Barraclough showered them with playful, word-radiating attention in his endearing, if esoteric, 2015 collection (excerpted below).** As we hit the summer solstice this weekend, the solar influence on our days grows unignorable. However, it’s best to avoid any direct observation of the sun, which could lead to solar retinopathy and damage that precious macula of yours.

Fig. 2. Étienne Léopold Trouvelot, “Plate IV. Solar Prominences.” (Wellcome Collection). Rpt. from Annals of the Astronomical Observatory of Harvard College, Vol. VIII (Cambridge: John Wilson and Son, 1876).

Readings

1. Whereas you, Galileo, son of the late Vincenzio Galilei, Florentine, aged seventy years, were denounced to this Holy Office in 1615 for holding as true the false doctrine taught by some that the sun is the center of the world and motionless and the earth moves even with diurnal motion; for having disciples to whom you taught the same doctrine; for being in correspondence with some German mathematicians about it; for having published some letters entitled On Sunspots, in which you explained the same doctrine as true; for interpreting Holy Scripture according to your own meaning in response to objections based on Scripture which were sometimes made to you; and whereas later we received a copy of an essay in the form of a letter, which was said to have been written by you to a former disciple of yours and which in accordance with Copernicus’ position contains various propositions against the authority and true meaning of the Holy Scripture;

   […]

   We condemn you to formal imprisonment in this Holy Office at our pleasure. As a salutary penance we impose on you to recite the seven penitential Psalms once a week for the next three years. And we reserve the authority to moderate, change, or condone wholly or in part the above-mentioned penalties and penances.

Felice Cardinal d’Ascoli, et al. “Inquisition’s Sentence (22 June 1633).” The Essential Galileo. Edited and translated by Maurice A. Finocchiaro. Indianapolis, Indiana: Hackett, 2008. 279, 282.

2. For having risen and settled into her groove she begins to consider herself.

   For this she performs in eleven degrees.

   For first she does the Planck to strengthen core stability.

   For secondly she runs a malware scan for comets closing in.

   For thirdly she completes the paperwork for eclipses total, annular, and partial.

   For fourthly: flares.

   For fifthly she sorts her sunspots into pairs.

   For sixthly she gives neutrinos Priority Boarding.

   For seventhly she referees the arm-wrestling match between the upstart fusion and gravity.

   For eighthly she weaves flux ropes and thinks up skipping games.

   For ninthly she degausses her plasma screens.

   For tenthly she is profligate with her photons.

   For eleventhly: star jumps.

   For having considered herself she will consider her neighbors.

   For she runs a cloth around the ecliptic to make it gleam.

   For she oils the wheels of any planets gliding there.

   For she sends invites out to wallflowers in the Oort cloud.

   For she issues shadows for children to dodge as they make their way to school.

   For she shakes out her blankets for devotees of helioseismology.

   For when she takes her prey she plays with it to give it a chance.

   For one planet in nine escapes by her dallying.

   For in her morning orisons she loves the Earth and the Earth loves her.

Simon Barraclough. Sunspots. London, England: Penned in the Margins, 2015.

Supplementum

• Simon Barraclough, “From Sunspots.” Poetry (December 2015).

• Kate Howells, “It’s Not Magic; It’s Magnetic!” The Planetary Report (June 9, 2025).

• Adam Green, “The Trouvelot Astronomical Drawings (1882).” The Public Domain Review (Dec. 14, 2026).

• Richard Webb, “Spotty Record: Four Centuries of Sunspot Pictures.” New Scientist (September 16, 2013).

• “Glossary Term: Sunspot.” International Astronomical Union, Office of Astronomy for Education (2020-2026).

Fig. 3. “Early sunspot drawings from naked-eye observations,” rpt. from R. Arlt and J.M. Vaquero, “Historical sunspot records. Living Reviews in Solar Physics 17.1 (2020).

* The day after Galileo’s sentencing, the Pope commuted his sentence from actual imprisonment to house arrest, and the stellar observer was eventually permitted to return to his villa but barred from further research, teaching, or publishing activities.

** Barraclough’s homage to the sun is itself paying tribute to Christopher Smart’s remarkable eighteenth-century work, Jubilate Agno, specifically its anaphoric praise of the poet’s cat, Jeoffry.