What is Dark Energy?
Rethinking Cosmology and Its Theological Echoes.
In the modern cosmological model, one of the most profound revelations is that the vast majority of the universe is composed of something we neither see nor fully understand: dark energy. Representing approximately 70% of the universe’s total energy density, dark energy has upended long-standing assumptions about the structure, behavior, and ultimate fate of the cosmos. But what exactly is dark energy—and more provocatively, what questions does it force us to ask, not just in physics, but in theology, philosophy, and metaphysics?
At its core, dark energy is a term we use to describe a mysterious pressure that causes the accelerated expansion of the universe. It is most often modeled in cosmology by the cosmological constant (Λ), first introduced and then abandoned by Einstein, before being resurrected after the discovery of cosmic acceleration in the late 1990s. One common hypothesis suggests that dark energy may be the energy of vacuum fluctuations—the so-called zero-point energy of quantum fields pervading empty space. Unlike matter or radiation, the energy density of the vacuum does not dilute as the universe expands. In fact, this is what makes it a dominant force: as the fabric of space stretches, the total amount of vacuum energy increases.
However, it is scientifically inaccurate to say that “more dark energy is created” as space expands. Rather, if dark energy is a cosmological constant, its energy density remains unchanged per unit volume. Thus, as space expands, the total amount of dark energy increases, not because it is being “created” ex nihilo, but because the energy is intrinsic to space itself. This raises an ontological puzzle: is space itself a dynamic, energy-bearing entity, and if so, what is the nature of this energy that can neither be seen nor touched, but which governs the fate of galaxies?
By contrast, matter density—both “ordinary” (baryonic) and dark matter—does decrease with expansion, as it spreads thinner over the increasing volume. According to current estimates, Observable (baryonic) matter comprises about 4% of the universe. Conversely, Dark matter, detected only via gravitational effects, comprises about 26%, leaving dark energy with a dominant 70% share.
This numerical reality contradicts the deeply anthropocentric traditions inherited from Aristotelian and medieval Christian cosmology. According to those views, humans, made of matter and endowed with reason, were presumed central to the cosmic order. But if we now inhabit just 4% of all that exists—merely a statistical fluctuation in a sea of dark energy and dark matter—then our metaphysical self-image must evolve.
Furthermore, the Nicene Creed, which centers theological attention on “Light from Light”, metaphorically venerates photons as divine emanations. This language implicitly positions light—and by extension, the visible, knowable world—as sacred. Yet in light of modern cosmology, this symbolism comes under strain. Photons, like humans, are part of that same small 4% of ordinary matter-energy. The irony is poignant: what we once worshiped as divine—light—is, on the cosmic scale, a faint trace. The universe, it seems, is not made of light, but of darkness.
What then do we make of a universe where the dominant force is not visible, not intuitive, and in many respects, not interactive with the human senses or classical theology? Could the traditional identification of divinity with “light” be an anthropocentric misapprehension—a symbolic artifact of a pre-scientific cosmology?
To re-frame. If dark energy is the true substratum of the cosmos, a kind of latent nothingness more powerful than gravity and more expansive than matter, what does that say about our theological metaphors? In ancient Greek philosophy, “nothingness” was often seen as a privation—a lack. But what if the vacuum is not emptiness, but a generative, active field? In this sense, the dark energy that permeates space is not “nothing,” but perhaps closer to a primordial background from which all form emerges and to which it may return. Which is to say that the nature was conceived in, and by darkness and “we are children of darkness, not of light”, from a theological point of view?
This raises an even deeper question for both physicists and metaphysicians. Is dark energy fundamental, or emergent? Is it a property of space itself, or the residue of deeper quantum fields we have yet to discover? If emergent, what is it emerging from? Could a grand unified theory (or theory of quantum gravity) reveal dark energy to be a shadow of hidden dimensions, or even a reflection of the entanglement structure of spacetime?
And crucially—why this particular ratio: 70-26-4? Why does dark energy dominate now, rather than earlier or later? This “cosmic coincidence problem” remains one of the greatest mysteries in cosmology. It may suggest that our current epoch is temporally privileged—a radical echo of theological doctrines asserting humankind’s temporal centrality, now reborn in scientific garb.
Ironically, we may have come full circle. The language of science now echoes the awe once reserved for scripture: forces beyond comprehension, origins shrouded in mystery, and a cosmos in which the seen is a fraction of the real. But instead of light being divine, it is darkness that now holds the throne—not as evil or absence, but as the very ground of being.
The conversation between physics and theology is far from over. Rather than collapsing one into the other, we should allow the mystery of dark energy to invite deeper questions—about meaning, matter, and the metaphysical structure of reality. Science may not answer them all, but it gives us a better map of where the questions lie.
By Yvan David Danisa