Last week, before heading downstairs to inventory more Carte du Ciel charts, I revisited the Adler's new exhibit on the history and profound impact of telescopes, which was featured in my last post. Not surprisingly, I saw some things I hadn't seen the week before.
One of my discoveries was a quotation attributed to Galileo, which I decided on the spot would become the quote of the Week here, but reading it also reminded me that a number of figures in the extraterrestrial life debate believed the sun was undoubtedly inhabited, too; over a period of several centuries, the plurality of worlds included solar beings.
Detailed closeup of magnetic structures on the Sun's surface (H-alpha wavelength) on August 22, 2003. Credit: Swedish 1-m Solar Telescope (SST) operated by the Royal Swedish Academy of Sciences (Oddbjorn Engvold, Jun Elin Wiik, Luc Rouppe van der Voort).
Today it takes a special kind of imagination to consider life on our sun or any other star. After all, these are off-the-charts dynamic hostile places where nuclear fusion and superheated gas in the form of plasma reign, producing both electromagnetic radiation (visible light and heat are examples) and particle radiation (protons and electrons) with such force and in such quantities at such high temperatures for so long that the human mind can scarecly take it in.
But in the mid-15th Century, some 200 years after Western Christian scholars began studying Ancient Greek texts, a Roman Catholic philosopher, mathematician, and astronomer named Nicholas of Cusa (1401-1464), also known as Cusanus, published a work that discussed solar beings -- and other extraterrestrials -- for the first time in the context of the extraterrestrial life debate. His De docta ignorantia (Of Learned Ignorance) was essentially a theological and philosophical exploration of the limits of human rational thought and science. Today it is widely regarded as a masterpiece of the Middle Ages.
For Nicholas of Cusa, imagination and speculation were essential tools for moving beyond these limits. Only through them could human beings approach a more complete (but always imperfect) understanding of God and the cosmos. When applied to the subject of life beyond Earth this is what he said:
Life, as it exists on earth in the form of men, animals and plants, is to be found, let us suppose, in a higher form in the solar and stellar regions. Rather than think that so many stars and parts of the heavens are unihabited and that this earth of ours alone is peopled -- and that with beings, perhaps of an inferior type -- we will suppose that in every region there are inhabitants, differing in nature by rank and all owing their origin to God, who is the center and circumference of all stellar regions . . . Of the inhabitants then of worlds other than our own we can know still less, having no standards by which to appraise them. It may be conjectured that in the area of the sun there exist solar beings, bright and enlightened denizens, and by nature more spiritual than such as may inhabit the moon . . .
Image of an erupting solar filament above Active Region 9077 on July 19, 2000. Filaments are concentrated bundles of magnetic field filled with relatively cool gas, suspended in the solar corona. Credit: Dick Shine, NASA/TRACE
More spiritual or not, these possibly "bright and enlightened denizens" were part of a visible universe populated with creatures created by God.
Casanus knew this idea would be sensitive to Church leaders because of the difficulties other inhabited worlds presented for Christian beliefs about divine incarnation and redemption. But by presenting them within the context of a philosophy that included speculation and clear qualifications -- not to mention employing his own considerable political skills -- he managed to avoid serious trouble for himself.
In fact, apparently there was no trouble at all. Within a decade of publishing De docta ignorantia Casanus was installed as a cardinal of the church. Others interested in the subject of life beyond Earth at this time would not be so fortunate (see Next stop, below).
Interestingly, the existence of life on the sun was an idea that persisted even into the early 20th Century. Fewer and fewer persons trained in astronomy made the suggestion as time passed, but as Michael Crowe writes in The Extraterrestrial Life Debate, 1750-1900, no less than the eminent British astronomer John Herschel (1792-1871) thought the sun might be the home of "organisms of some peculiar and amazing kind." This was in 1861.
BTW, if you're fascinated by the images above as much as I am, there are 19 more to be found here. And more here.
It's remarkable how a few minutes of wandering can lead to so many places.
Next stop: The Life and Trial of Giordano Bruno
Banner bus photo credit: Dorothy Delina Porter
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