Uncovering the Universe: Why We Just Recently Realized It’s Dark Instead of Bright

Set against the vastness of space, our blue planet emerges above the desolate lunar landscape. This iconic photograph, “Earthrise,” was captured by Apollo 8 astronaut Bill Anders on Christmas Eve 1968.

Nearly six decades later, we regard this image as part of our narrative. Yet, envision a different earthrise where space is not a dark backdrop, but a vivid blue, akin to a sunny sky. Odd as it may appear, this was the vision held by many Europeans for centuries.

Our comprehension of the cosmos has evolved significantly over time, influencing how we perceive our place within it. The shift from an earth-centered to a sun-centered universe, along with the transition from a finite to an infinite cosmos, prompted a profound reevaluation of humanity’s role in the grand scheme. The change from a vibrant to a dim universe is equally crucial, yet it remains largely overlooked in our historical narratives.

Recently, through my scholarly work in literary and scientific history, I have sought to trace the timeline of this transformation. At what point did our universe metaphorically turn dark? What did this shift imply for humanity?

Reflect on the account given by Domingo González, the hero of Francis Godwin’s 1638 science fiction novel, The Man in the Moone. González travels to the moon in a swan-powered vehicle and notes a scarcity of stars. Even those he does see are dim. He observes, “It was always daytime for some reason, yet the stars appeared faint, similar to the moon’s glow in daylight.” Why are there fewer stars in his experience? Why do they appear washed out? Because, in his narrative, space is akin to the daytime sky, where the sun drowns out the luminosity of stars.

From our viewpoint, González’s reality seems inverted. In his portrayal, daytime reveals our true nature, while night conceals us within Earth’s shadow. Yet, ascending to space at midnight, we would eventually emerge from darkness into eternal daylight.

While González omits mention of a shadow, we glimpse it in another early space narrative by John Milton, Paradise Lost. As Milton’s Satan nears Earth, he remarks upon “a whirling canopy / a spreading shadow of the night.” If you visualize pre-modern eras, adding this shadow to your image of earthrise transforms it. A dark cone emerges from the jagged globe, plunging into the azure sky and vanishing beneath the lunar horizon.

Additional authors elucidate why the Universe is imagined as not merely bright, but blue-hued. The prevalent rationale is that the “firmament” was envisioned as blue. Walter Charlton, a contemporary of Milton, remarked this notion was widely shared “by many transcendental thinkers, as well as the average populace.” Observing the daytime sky, they believed they were witnessing the universe’s limit.

The Path to Earthrise

This luminescent universe also manifests in visual art. A comparison with Apollo 8 is particularly pertinent. Hours after capturing earthrise, the crew transmitted radio messages from lunar orbit to Earth. Commander Frank Bowman extended Christmas wishes and recited the biblical creation tale. For the first time, humanity achieved a god-like vantage point of the radiant blue planet glistening against the abyss. In contrast, when pre-modern artists portrayed these scripture moments, they often rendered a dim planet against a bright celestial expanse. To reimagine earthrise, picture one of these shadowed Earths ascending above the lunar surface instead of the iconic “blue marble.”

It was not just poets and artists who envisioned such a realm. Philosophers and scientists also entertained the concept. Aristotle remarked on “the shadow of the earth (termed night).” Two millennia later, Copernicus similarly wrote, “While the rest of the universe is illuminated and radiant, the night signifies nothing but the shadow of the Earth, extending in a cone and culminating at a point.”

This perspective was not unreasonable; early European scholars lacked compelling evidence to argue otherwise, particularly concerning the light-refracting properties of the universe and Earth’s atmosphere. Without such evidence, why suspect that night predominates and day a rarity? What led pre-modern Christians to diverge from millennia of tradition and perceive heaven—not as eternal brightness, but infinite darkness?

This does not imply that luminous spaces were universally accepted in pre-modern thought. For instance, scholars within the Islamic tradition favored the concept of dark spaces starting in the 9th century, yet this perspective seems to have been less influential in the West. In any case, the notion of a dark universe had to be re-established among 17th-century European thinkers.

During this period, significant advancements in atmospheric science emerged. Notably, the term “atmosphere” was coined in the 17th century, with Walter Charlton among the first to utilize it in English. His view of the universe acts as a transitional development in this narrative: a universe that oscillates between brightness and darkness based on an observer’s orientation towards the sun. Although Charlton described a dark universe, he noted that it was “not nearly as deep blue as many presume,” and filled with countless tiny particles or “atoms,” which he speculated could impact visibility. In contrast, Otto von Guericke, who endorsed the infinite universe and conducted pioneering vacuum experiments, postulated that in an “unblemished” and “void” space, devoid of illuminated objects, we would perceive “nothing but shadows.”

Thereafter, dark space gained traction among European scientists and thinkers informed by these scientific advancements. However, this marks only part of the narrative, as visions of bright spaces lingered in cultural imaginations for centuries.

Fast forward to 1858, when astronomer James Gall envisioned his foray into the void for a Victorian audience, exclaiming, “As I look around me, how peculiar! The heavens are pitch black.” While Gall acknowledged the darkness of space, he doubted the audience’s awareness of this fact. It wasn’t a naive child or uninformed individual believing in a “giant blue sphere,” but the renowned literary historian David Masson in 1880 who clung to this isolated imagery, which persisted well into the 1920s, right at the brink of the Space Age.

Thus, we confront a dual narrative of a decline in our cosmic imagination alongside the unexpected evolution of these ideas. Some of the most striking evidence is found in literature, especially in space travel narratives, which were initially recognized by literary scholars such as C.S. Lewis and more recently John Leonard. Nevertheless, this aspect has yet to receive thorough investigation, and its cultural ramifications remain largely unexamined.

The implications are significant, often concealed in plain sight. Prominent images such as earthrise have reshaped our perceptions of our planet and its environmental context. The view of Earth as “perfect” and “blue” has also rendered it “fragile,” symbolizing the perils of nuclear conflict and climate change, as well as underscoring the call for political unity and ecological stewardship. What is less acknowledged, however, is that this transformation arose not only from a fresh perspective on Earth, but importantly on the vastness surrounding it.

For millennia, the entirety of Earth has been envisioned, represented, and contemplated. Yet, much of it was depicted within brilliant space, eliciting markedly different responses. Hence, the influence of earthrise was indeed more profound than commonly appreciated. The mass circulation of such imagery has obliterated even the faintest remnants of a once-bright universe and firmly imprinted its inversion into collective consciousness. The Earth stands not merely as “blue” or “fragile.” While it may appear thus against the cold, dark expanse surrounding it, it has transitioned into both a scientific reality and a cultural perception.