Why we only recently discovered space is dark not bright

The Blue Earth rises above the barren surface of the Moon against the black emptiness of space. This famous photograph “Earthrise”was taken on Christmas Eve 1968 by Apollo 8 astronaut Bill Anders.

Almost six decades later, we take this image for granted. But imagine something else Earthrisein which space is not black, but bright blue, like a clear daytime sky. As strange as it may seem to you, this is how most Europeans thought of it for centuries.

We know that our understanding of the universe has undergone other major changes that have had far-reaching consequences. For example, the transition from the Earth at the center to the Sun and from a finite to an infinite Universe was not only a scientific discovery. They forced people to truly rethink their place in space. The transition from a bright universe to a dark one is of comparable importance, but it is almost lost in history.

In recent years, thanks to my research In the history of literature and the history of science, I have tried to piece together when this shift occurred. When, so to speak, did space go dark? And I caught myself asking: what happened to us in the process?

Consider the testimony of Domingo Gonzalez, the protagonist of Francis Godwin's first English science fiction novel, 1638. Man on the Moon. Traveling to the Moon aboard a Swan-powered spacecraft, Gonzalez reports that he saw very few stars – and these few, “since it was always day, I saw at all times the same, shining not brightly, as we do on Earth… we see them at night, but whitish in color, like the Moon during the day with us.” Why does he see fewer stars from Earth than we do? And why are they pale, like the moon seen in the daytime sky? Because his space is just the daytime sky. The sun darkened the light of the brightest stars and completely drowned out the light of the fainter ones.

From our point of view, Gonzalez's universe is turned upside down. According to his version, during the day we see it as it really is, while at night it is covered by the dark shadow of the Earth. But if we were to rise into space at midnight, we would eventually burst out of the shadows into the eternal day beyond.

Gonzalez doesn't mention the shadow, but we glimpse it in another early tale of space travel, John Milton's. Lost Paradise. As Milton's Satan approaches the Earth, he sees “the swirling dome / Of night's spreading shadow.” Representing pre-modern Earthrisethen we should add this shadow to the picture – a dark cone extending from the convex planet into the blue sky and disappearing beyond the lunar horizon.

Other authors explain why space is not just bright, but bright blue. The most common explanation is that the “firmament”—variably represented as the vault of space—was blue. This point of view, as noted by Milton’s contemporary, the atomist philosopher Walter Charlton, is held “not only by the vulgar, but also by many transcendentally educated heads.” Looking at the daytime sky, they thought they were simply looking at the edge of the Universe.

Path to Earthrise

This universe also appears in the visual arts. And here again the comparison with Apollo 8 instructive. A few hours after the capture EarthriseThe crew delivered a radio transmission to Earth from lunar orbit. Commander Frank Borman wished the earthlings a Merry Christmas and read the biblical account of the creation of the world. For the first time, people gained such a god-like view of their blue planet sparkling in the black abyss. But when pre-modern artists illustrated these same Bible verses, they often painted them in reverse: dark Earths hanging in azure skies. To complete the alternative Earthriseimagine one of these dark Earths, rather than the familiar “blue marble”, rising above the lunar surface.

And these were not only poets and artists. Philosophers and scientists have also imagined such universes. Aristotle describes “the shadow of the earth (which we call night).” Two millennia later, Copernicus does the same, writing that “while the rest of the Universe is bright and full of daylight, the night is clearly nothing more than the shadow of the Earth, which extends in the shape of a cone and ends at a point.”

There was nothing irrational in such views. Early European thinkers simply did not have convincing evidence to the contrary, especially regarding the nature of outer space and the light-refracting atmosphere of the Earth. Without such evidence, why suspect that night is the rule and day the exception? What reason had the pre-modern Christian to break with centuries of tradition and no longer regard heaven – the abode of God, angels and blessed souls – as a kingdom of eternal light, but as a kingdom of eternal darkness?

This is not to say that bright space was universal, even in the pre-modern era. Thinkers in the Islamic world, for example, accepted the dark space from the 9th century onwards, although the spread of their views in the West appears to have been limited. Apparently, the dark space had to be rediscovered by European thinkers in the 17th century.

First, significant advances were made in the scientific understanding of the atmosphere during this period. Indeed, “atmosphere” is a 17th-century word, and one of the first to use it in English was Walter Charlton, whose universe can be described as the missing link in history: neither bright nor dark, but changing from one to the other as the observer turns toward and away from the sun. This is because Charlton's universe is still bounded by the sky – albeit black, “not azure as many believe” – ​​and is also filled with swarms of tiny particles or “atoms”, which forces him to speculate about their visual effects. But for Otto von Guericke, who recognized a disconnected, infinite universe and conducted pioneering experiments to study the vacuum, space is just that: space. If we found ourselves in such a “pure”, “empty” space, where “neither below us nor in front” of us “is there a body illuminated by the sun,” we would “see nothing but a shadow.”

From this point on, dark space was increasingly accepted by European scientists and scientifically literate thinkers. But the story does not end there, because the bright space remains in the popular imagination for centuries.

Fast forward to 1858: astronomer James Gall imagines ascending into space in a work addressed to the general Victorian reader: “We look around and, oh, how strange! The skies are black.” Gall knows that space is black, but he doesn't expect his audience to know it. And this audience is not necessarily uneducated in other areas. It is not the ignoramus or the child who still believes in 1880 that the universe is a “vast blue sphere,” but the eminent literary historian David Masson. Isolated cases continued into the 1920s, at the very threshold of the space age.

Thus, we are dealing not only with a lost, but also with a surprisingly recent shift in our cosmological imagination. Because some of the most striking evidence appears in literary works, especially stories about space travel, it was first noticed by literary scholars: K.S. Lewis and, more recently, John Leonard. But it has not yet received long-term study, and its cultural impact remains almost entirely unknown.

This influence has been profound, although it is often hidden in plain sight. For example, it is widely accepted that images such as Earthrise have changed our planetary and environmental consciousness. The earth became “whole” and “blue” but also “fragile”: a symbol of the imperatives of political unity and environmental sustainability, as well as the threat of nuclear war and man-made climate change. However, it is not recognized that this transformation occurred not only because of a new look at the planet, but also at what surrounded it.

Entire Earths have been imagined, depicted and speculated on since ancient times. But most of them floated in bright universes, causing completely different reactions. Influence Earthrise therefore there was even more than was usually expected. Once such images entered the mainstream, they erased even the last remaining vestiges of the old, bright cosmos, burning into the popular imagination its exact inversion: Earth as a glowing oasis in a dark cosmic desert. The earth has never been “blue” or “fragile” as such. This is how it looked against the background of the deadly darkness surrounding it, which has now become not only a scientific, but also a cultural and psychological reality.

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