Medieval Friar Anticipated James Webb Telescope’s Discoveries with Insights on Planetary Composition
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A 13th-century Dominican friar’s groundbreaking work on light and color challenged prevailing scientific beliefs and foreshadowed modern astrophysics’ understanding of planetary composition, remarkably mirroring the methods of the James Webb Space Telescope.
During the 1240s, Richard Fishacre, a Dominican friar teaching at Oxford University, proposed a radical idea: the stars and planets aren’t composed of a unique “fifth element,” but rather the same elements found on Earth. This challenged the long-held scientific orthodoxy rooted in the philosophies of Aristotle. For centuries, medieval physics adhered to the notion of a special celestial element – the “fifth element,” or quinta essentia – distinct from the terrestrial elements of fire, water, earth, and air.
This “fifth element” was believed to be perfect and unchanging, forming the basis of nine concentric celestial spheres surrounding Earth, with planets and stars attached to them as condensed versions of this ethereal substance. Each of the first seven spheres was thought to host a planet, while the outermost spheres contained the stars and heaven itself.
Challenging the Celestial Status Quo
Lacking access to modern telescopes or the ability to analyze rock samples, Fishacre boldly rejected the concept of a unique celestial element. He posited that the stars and planets were, in fact, composed of the same four elements present on Earth. His reasoning stemmed from a keen understanding of how color and light behave.
Fishacre observed that color is typically associated with opaque bodies, which are always composite – meaning they are made up of multiple terrestrial elements. However, the light emitted by stars and planets often displays faint colors, such as the reddish hue of Mars and the yellowish glow of Venus. This, he argued, indicated that these celestial bodies were also composite and therefore constructed “ex quattuor elementis” – “out of the four elements.”
The Moon as Proof
In Fishacre’s view, the most compelling evidence against the “fifth element” came from observing the moon. It possesses a distinct color and, crucially, periodically eclipses the sun. If the moon were made of the transparent fifth element, even in a highly condensed form, sunlight should pass through it unimpeded, like through a pane of glass. However, this is not the case.
Therefore, Fishacre reasoned, the moon must be composed of the same elements found on Earth. If this held true for the moon – the closest celestial body – it logically followed that it applied to all other stars and planets as well.
A Risky Proposition
Fishacre was acutely aware that his ideas were controversial. He wrote that proposing this position would invite harsh criticism, stating, “If we posit this position, then they, that crowd of Aristotelian know-it-alls (scioli aristoteli), will cry out and stone us.”
His fears were realized. In 1250, his teachings were publicly denounced at the University of Paris by St. Bonaventure of Bagnoregio, a Franciscan friar who derided those “moderns” – like Fishacre – who dared to question Aristotle’s teachings on the celestial fifth element. Accounts suggest Fishacre faced significant opposition, even physical threats, for his views.
Modern Science Validates a Medieval Insight
Contemporary astrophysics has definitively vindicated Fishacre’s position. The stars and planets are not made of a special fifth element, but rather from many of the same metals and elements found on our planet. The James Webb Space Telescope, for example, recently confirmed the presence of high quantities of water and sulphur dioxide in the atmosphere of TOI-421 b, a Neptune-like exoplanet located 244 light-years away.
Remarkably, the method used by the James Webb Space Telescope – transmission spectroscopy – bears a striking resemblance to Fishacre’s approach. The telescope detected subtle variations in the brightness and color of light emitted by TOI-421 b, variations that could only be caused by the presence of water and sulphur dioxide.
Given the intense criticism he faced, Fishacre would undoubtedly be gratified to know that, nearly 800 years after his death, modern astronomy, just like him, is utilizing light and color to demonstrate that distant stars and planets are all constructed from the same fundamental elements.
