What if there were no stars?

How has the observation of stars shaped the course of human history? Would we be the way we are in a world without stars? Roberto Trotta answers these questions in Starborn – How the Stars Made Us (And Who We Would Be Without Them) (2023), a work that reads like poetry.

«It is often said that we are made of stardust, the atoms of our bodies having been created in the atomic furnaces of long-dead stars. But more than that, the simple fact that we could see the stars, adore them, and study them is the secret ingredient that made us who we are today»¹. Roberto Trotta, a professor of theoretical physics and cosmologist, owes much to the stars: from academic research to meeting the woman who would become his wife. «They had silently guided my own life. Just how much, I wondered, had they steered the course of humanity?»². To answer this question, in his latest essay Starborn – How the Stars Made Us (And Who We Would Be Without Them) , he creates Caligo: a world without stars, rather like the English cities in the late 19th century or the Faroe Islands in winter.

The starless nights of Caligo

«No one on Caligo has ever seen a star» Trotta writes. Caligo, meaning fog or mist in Latin, is an imaginary counterfactual Earth, covered by a constant layer of clouds³ that tinge it grey and never reveal what lies beyond: the blue sky, the stars, the Sun, or the Moon. Caligo is a planet that would be hard to find in nature because, if it existed, «its initial conditions would not allow humans to emerge»⁴. Trotta creates it, then, as a thought experiment to respond to the provocation of physicist and mathematician Henri Poincaré, who in The Value of Science (1905) wrote: «Think how diminished humanity would be if, under heavens constantly overclouded, as Jupiter’s must be, it had forever remained ignorant of the stars. Do you think that in such a world we should be what we are?»⁵. The answer running through the entire essay – a “poetic essay” that intersperses the more scientific parts with The Caligo Tales – is that no, we wouldn’t be who we are. This is clear from the delicate balance of determinism and chance that rules the field of biological evolution.

In fact, as Trotta explains, if it existed, the luminous veil of Caligo’s clouds would alter the trajectory of biological evolution in many ways: it would push far more creatures to adapt to the lack of light with larger eyes, exceptional hearing and smell, and the ability to navigate using sonar; it would favour an ecosystem of plants where low-energy photosynthesis is more efficient, like broadleaves and oceanic algae. It would enable too many differences compared to that fortuitous chance in which «the flower of Homo sapiens, one bud on the unpredictable bush of life, had bloomed in the night—opened by the light of the stars»⁶.

Fifty thousand years ago: since the appearance of Homo Sapiens, the trajectories of Caligo and the Earth diverge. From this precise moment in the “funnel of history”, that the Caligo Tales are juxtaposed with scientific prose, projecting the reader into the past to meet characters like the Bison-Seeker, the Fire-Keeper, and the Cloud-Watcher, as they learn to fight the Bedeviled and try to understand the workings of the Cloud, their starless sky. Under the Cloud, only lightning – flashes revered as something magical and divine – can illuminate the night, something one can get lost in, both physically and mentally, as happens to one of the protagonists, Freshwater, because there are no stars to mark the passage of time and to guide through space.

Why stars guided Homo sapiens

«Some of today’s highways, including Victoria Highway in the north and the Great Western Highway, are said to trace the Dreaming tracks of Aboriginal people⁷» Trotta writes. Dreaming tracks or soundlines are nothing but the mappings we have created in ancient times to navigate by night using the stars. «The Wardaman peoples» Trotta explains «memorized the route by associating individual stars with specific markers along the way—a river crossing, a waterhole, a bend in the road, a stone arrangement, a marked tree. The imagined path connecting the stars represented the road the traveler would tread on the ground. […] Each journey had its own songline, which unfolded along the track connecting the wayfinding points among them, a ritual set of directions that created a chanted, living bridge between land and sky»⁸. Like whales that navigate using magnetic lines, or flocks of birds that must leave the North Star behind to migrate to warmer climates, humans as well have learnt to read and recognise the sky to orient themselves. This is part of what has made us who we are.

In the essay, Trotta argues that our knowledge of the sky gave sapiens an advantage over other animal species, including Neanderthals, who were less familiar with stars and constellations.

Early Homo sapiens used stars and lunar cycles to plan future events and seasonal changes, thus securing more food and reproductive opportunities. The stars were the first kingmaker, because, as Trotta writes, «Those who could infallibly lead their tribe to shelter by following the stars, or reliably provide meat during a full Moon»⁹, would assume higher status within the group. Trotta mentions, unsurprisingly, the anthropologist Chris Knight¹⁰, according to whom the entire primordial social organisation of the Sapiens may have revolved around the lunar cycle, and concludes the chapter devoted to the “weight of the stars” during the beginnings of human history with a touch of poetry and suggestion that, like the moon, cyclically return throughout the text. Whether or not Chris Knight’s and Alexander Marshack’s hypotheses are correct, it is suggestive that to this day, the same ancient root me-, meaning “to measure,” links together in a faint echo of long-lost associations the words month, meal, menstruation—and moon¹¹.

Losing Prometheus

«In a short ten thousand years» writes Trotta, «the naked ape has managed to go to the Moon».

But how ephemeral humankind’s achievements appear when considered against the deep time that metes out the life of planets and stars!»¹². Modern science and life have been built on astronomical foundations and the need to understand our place in the cosmos. The ability of early humans to look at the sun, the moon, and the stars to place themselves in time and space on Earth undoubtedly led – Trotta argues – to magnificent inventions such as the astrolabe and the sextant, to the great minds of Copernicus, Galileo, Laplace, and Gauss, who refined the scientific method, charted the course for understanding planetary motion, and invented new mathematical models and measurements. Not only that, it has triggered the development of technologies that are inspired by the stars and want to reach them, no longer to admire them but to live next to them and in them. However, Trotta warns, stars «are not an escape route»¹³.  We must return to gazing at the stars without aiming for them in a Promethean race towards a new world to inhabit. The text’s invitation is, instead, to direct our minds towards redistributing resources on Earth and becoming “good ancestors”, because «It is all too easy to forget about the stars, hidden from our view by light pollution, peppered with artificial satellites, or confined to a desktop background». Returning to admire the stars in everyday life, in summer nights, without setting them as the ultimate goal of humanity’s history, offers a solution for an Earth that increasingly resembles Caligo, submerged under a blanket of toxic clouds.

Returning to the Wardaman, Trotta gathers the words of Bill Yidumduma, an elder from the Aboriginal community, who says: «each night where we were going to travel back to the camp…the only tell was about a star. How to travel? Follow the star along». Although the images from the James Webb Space Telescope and other observatories are glorious, mysterious, and profound, and although we can view them on our bright screens, the Wardaman and Trotta remind us to «embrace the stars» in the sky, following a path different from the one pursued so far in our conquest of space. A path that passes through soundlines, dreaming tracks, and the memory of what a world without stars would be like – a place where one could lose oneself entirely.

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1. Based on Trotta, R. (2023). Starborn: How the Stars Made Us – and Who We Would Be Without Them. Hachette UK., eBook. ↩︎
2. Ibidem. ↩︎
3. The blackish-grey clouds, which bring non-storm precipitation referred to in the text, are scientifically called nembostratus. ↩︎
4. Ibidem. ↩︎
5. Ibidem. ↩︎
6. Ibidem. ↩︎
7. Ibidem. ↩︎
8. Ibidem. ↩︎
9. Ibidem. ↩︎
10. The text taken as a reference is: Knight, C. (2013). Blood relations: Menstruation and the Origins of Culture. Yale University Press. ↩︎
11. Ibidem. ↩︎
12. Ibidem. ↩︎
13. Ibidem. ↩︎