For centuries, the study of light has been central to our understanding of the visible world, prompting inquiries about color, rainbows, and the nature of light itself. Esteemed thinkers like Aristotle, Roger Bacon, Isaac Newton, Michael Faraday, Thomas Young, and James Clerk Maxwell grappled with these questions. However, the late 19th century marked a pivotal shift, largely influenced by Maxwell’s work. The focus of physics transitioned from the observable to the unseen, revealing that light was just a fraction of a broader spectrum that included invisible fields.

Today, the realm of physics often deals with entities that escape our direct perception, such as force fields and minute particles invisible even under advanced magnification. Our everyday experience allows access to only a minuscule part of reality. Innovations such as telescopes sensitive to radio waves, infrared radiation, and X-rays have vastly broadened our understanding of the universe. Meanwhile, electron microscopes and other sophisticated instruments have uncovered the hidden microworld, exposing phenomena beyond our visual capacity. The forefront of physics now entertains theories of parallel worlds and enigmatic entities, aptly named dark matter and dark energy.

This exploration beyond visibility is a critical narrative in science, yet it is more intricate than it may seem. The quest to comprehend what lies “beyond the light” has a lengthy history, with humanity relying on myths and folklore before the advent of scientific inquiry. Rather than being discarded, these narratives have been reimagined as science progresses. Researchers delving into the invisible often face knowledge gaps and limitations in experimentation, prompting them to unconsciously draw on these age-old stories. Such tales can sometimes inspire fruitful scientific ideas, but there is a risk of mistaking them for established theories.

A retrospective on the history of the unseen illustrates how mythological narratives can inspire scientific inquiry, often leading to truths far stranger than the stories they replace.

The Enigma of Invisible Light

In 1908, British physicist Edmund Fournier d’Albe proposed a controversial theory suggesting that the human soul consists of invisible particles he termed "psychomeres," which he claimed possessed a primitive form of intelligence. He estimated that these particles collectively weighed around 50 milligrams and posited that they could explain various paranormal phenomena, from ghosts to the biblical burning bush. While his claims may seem outlandish today, Fournier d’Albe was a respected figure in radio telecommunications, arguing against the dismissal of unseen entities due to their invisibility.

He asserted, “We must resolutely combat the tendency to look for the unseen beyond the seen. The unseen is all about us… a single octave in the gamut of light-waves impresses our retina, revealing a very small proportion of what would be visible to a more completely equipped intelligence.” In essence, he and his contemporaries believed there was much more to reality than meets the eye.

Historically, concepts that remain unseen were often categorized as occult, implying they were hidden rather than inherently supernatural. This led to the association of various imaginary phenomena—ghosts, spirits, telepathy, and other psychic forces—with the occult. In the early days of scientific exploration of the invisible, many scientists saw no clear boundary between these occult notions and empirical science, leading them to create elaborate narratives to bridge the two. Particularly during the Victorian era, some theorized that intelligent beings existed on both subatomic and cosmic scales, while others believed high-frequency waves could facilitate thought transfer or that immortal souls aligned with thermodynamic laws.

The quest to understand the nature of light initiated this shift toward the invisible. Faraday introduced the concept of an invisible field to explain electricity and magnetism in the early 19th century. By the 1860s, Maxwell had formulated equations demonstrating the relationship between these two forces, indicating that electromagnetic waves traveled through space at the speed of light. He established that electromagnetic waves, including visible light, could exhibit a range of wavelengths beyond the visible spectrum.

This groundbreaking insight was soon validated. In 1887, Heinrich Hertz showed that variations in electrical currents produced long-wavelength radiation, later known as radio waves, and by the late 1890s, Guglielmo Marconi demonstrated the potential of radio waves for long-distance communication. This was revolutionary, as it allowed for wireless communication, a significant leap from previous methods reliant on physical connections.

The simultaneous rise of spiritualism during this period, where mediums claimed to contact the deceased, created a fertile ground for scientific exploration into the invisible. The new physics offered potential explanations for telepathy and other supernatural claims, while belief in unseen forces opened the door for unconventional ideas in physics.

As scientists began to explore the properties of invisible fields, they speculated about non-material beings inhabiting unseen dimensions. Maxwell’s colleagues, Peter Guthrie Tait and Balfour Stewart, published The Unseen Universe in 1875, proposing that the ether—thought to be the medium for Maxwell's waves—served as a bridge between physical and spiritual realms. This intertwining of physics and spiritualism fostered a vision of space teeming with unseen intelligences, waiting to be discovered.

The discovery of X-rays by Wilhelm Röntgen in 1895 further fueled these notions. X-rays, invisible yet revealing, could expose bones beneath the skin, creating a sense of unease about mortality. Public demonstrations where people could view their own skeletons on screens drew crowds eager to witness the unseen. X-ray photography became likened to “spirit photography,” which sought to capture ghostly apparitions through double exposures.

During this era, claims regarding invisible rays proliferated. From cathode rays to the “uranic rays” discovered by Henri Becquerel, the understanding of radiation evolved rapidly. People believed these invisible emanations held life-enhancing properties, leading to the misconception that radioactivity had miraculous healing powers. Advertisements from the early 20th century even promoted radium-infused products as health remedies, a belief that persisted until the harmful effects of radiation became clear.

Factories of the Unseen

The revelations of the late 19th century highlighted that the universe we perceive is merely a fraction of what exists. A long-standing belief in spirit realms, dating back to the Middle Ages, suggested that invisible demons and entities surrounded humanity. These ideas provided a framework for interpreting the emerging concept of an “invisible universe.” Physicist William Barrett, co-founder of the Society for Psychical Research in 1882, theorized the existence of human-like invisible “elementals.”

William Crookes, a prominent chemist and former President of the Royal Society, became notorious for his belief in spirits, influenced by mediums of the time. He created a device called the radiometer, which demonstrated the pressure exerted by light through rotating vanes. While the initial purpose stemmed from a belief in the paranormal, the radiometer contributed to scientific advancements regarding light properties.

Crookes also introduced the concept of “radiant matter,” which he believed existed in a realm between ordinary matter and pure light. His conjectures, while unfounded, led to significant discoveries, including the identification of electrons and X-rays, and ultimately contributed to the development of television technology. Many early television pioneers, including Crookes and John Logie Baird, were influenced by spiritualistic beliefs.

Both radio and television can be seen as “ghost factories,” creating disembodied representations of ourselves. These mediums blur the lines between presence and absence, allowing the illusion of contacting distant individuals. The Internet, too, has become a space rife with spectral presences, with the potential for pseudonymous identities to emerge from the digital ether.

Technological advancements do not eliminate superstitions but rather reshape their environments. While science undeniably pushes back against ignorance, it often overlaps with the imaginative impulses that characterize human inquiry. In contemporary science, where the boundaries of understanding are tested, the distinction between fantasy and reality can become blurred.

Exploring Hidden Dimensions

Consider the Many-Worlds Interpretation of quantum mechanics, a concept with no consensus among physicists. This theory suggests the existence of parallel universes, each reflecting different outcomes from quantum equations. Although influential, the interpretation raises questions about the nature of consciousness within these parallel realities.

Similarly, the “brane” worlds proposed by string theory introduce additional dimensions beyond our four-dimensional understanding. These concepts, while mathematically compelling, lack direct experimental validation, leading to speculation about their implications for the existence of alternative realities.

Dark matter and dark energy, while rooted in observational astronomy, remain elusive, with theories emerging to explain their gravitational effects without direct evidence. These concepts often reflect our attempts to comprehend the unknown, paralleling the struggles of earlier scientists grappling with invisible forces.

Ultimately, the act of theorizing about the unseen is a fundamental aspect of scientific progress. Scientists employ these constructs to bridge gaps in knowledge, often drawing from historical narratives and myths. Such imaginative thinking is essential for navigating the complexities of the universe, even if it leads to misconceptions. The challenge lies in balancing creativity with scientific rigor, ensuring that the pursuit of knowledge remains grounded in empirical evidence while allowing room for exploration of the unknown.