Enter the Invisible Universe

In the age of the extended senses, what you see is just a tiny fraction of what you can perceive.

“What distant and different beings in the various mansions of the universe are contemplating the same one at the same moment! Nature and human life are as various as our several constitutions. Who shall say what prospect life offers to another? Could a greater miracle take place than for us to look through each other's eyes for an instant?” — Henry David Thoreau, Walden (1854)

That passage from Walden had a huge impact on me the first time I read it. Back then, I was a prematurely cynical high-school junior: well-educated in the theoretical sense but still largely sheltered from the great and terrible realities of the world. I rolled my eyes extravagantly at a lot of Thoreau’s pontifications about the transcendental rewards of communing with nature. When I hit this particular passage in the book, though, I paused as I felt the warm, unexpected sensation of a new idea taking hold.

We truly are prisoners in our bodies, I thought, sentenced for life to look at and think about the world from a single perspective. Thoreau was right. It may seem an obvious insight to an adult, but I had never before encountered the idea articulated in such clear, direct terms. (Recall that I was 16 at the time. Recall, too, that this was the early 1980s, before the flood of body-swap movies jammed the Hollywood version of Walden’s insight into multiplex cinemas all across the United States.) I teared up a little with self-pity at all the other perceptions of the world that I would never know because I could never see those “various mansions of the universe” through any eyes other than my own.

Then, less than two years later, I had my second epiphany: Thoreau was wrong. Human biology may have trapped us in a single perspective, but we are no longer defined entirely in terms of our organic limitations. Human technology has sprung us free.

By this time, I was an intern at NASA’s sprawling Goddard Space Flight Center in Greenbelt, Maryland, working odd jobs in the center’s Laboratory for High Energy Astrophysics. The scientists I worked with were so matter-of-fact about their work—so deeply absorbed in the specific technical issues and scientific questions they were attempting to resolve—that it took a while for me to take in the big picture.

The Laboratory for High Energy Astrophysics (LHEA or “code 660” in NASA lingo) was home base for the astronomers who studied the universe in x-rays and gamma rays. The folks working in the drab cinder-block offices around me were developing balloon-borne telescopes and satellite observatories to study flashes of radiation from pulsars and black holes and supernova explosions. These instruments had to travel above Earth’s atmosphere, because x-rays and gamma rays do not penetrate the air.

Humans cannot sense x-rays and gamma rays. No animal has ever evolved to perceive these rays, because high-energy radiation is not a part of the normal sensory environment on the surface of our planet. X-rays and gamma rays are fundamentally invisible, biologically speaking—and yet we now can see them. My NASA coworkers were looking at them all the time, creating pixilated images of the sky that revealed the heavens in their glow of forbidden, violent electromagnetism.

Scientists like the ones at Goddard had developed technological eyes that enabled them to gaze out onto the invisible universe. Then they shared the results in trickle-down fashion: first in journals and at academic conferences, then in lectures and press releases, and eventually in newspapers, magazines, and TV news.

As those astronomical images circulated, more and more people shared shared a vision of the x-ray and gamma-ray universe. More and more people got to see reality through eyes that were not our own, but that now belonged to all of humanity, collectively. What could be more transcendent than that?

Transcendent Technology

It would be anachronistic (and quite silly) to scold Henry David Thoreau for failing to consider the possibility of x-ray satellites, a half-century before Wilhem Röntgen’s discovery of x-rays and more than a full century before the first artificial satellite. But it is revealing to consider how Thoreau framed his conception of the impossible “miracle” of looking out upon the world through eyes other than your own.

For Thoreau, human perspective was rooted in personal identity, and ultimately defined within the framework of philosophy and ethics. He held to this view even at a time of extraordinary discoveries and innovations. William Herschel in England had discovered infrared rays (invisible emanations beyond the red end of the spectrum) in 1800. Johann Ritter had detected invisible, beyond-blue ultraviolet rays just a year after that. During the 1830s, the new method of capturing images known as “photography” was a public sensation. By 1854, the outward expansion of the senses through technological means was already well underway.

Thoreau was well aware of these developments. Nevertheless, he didn’t regard the technological expansion of the senses, no matter how spectacular, as a true expansion of human insight. “Objects are concealed from our view, not so much because they are out of the course of our visual ray as because we do not bring our minds and eyes to bear on them,” he wrote in his 1854 Journal. Although Thoreau was intrigued by the power of technology to make the invisible visible, he doubted that the resulting images would generate the sense of a “grand and beautiful” reality that transforms an objective observation into something subjectively, personally meaningful.

Here’s where I strongly disagree with Thoreau. Even as he came to embrace the notion that humans are a part of nature, he failed to appreciate that, by extension, human technology is a part of nature as well. Our ability to perceive infrared and ultraviolet rays emerged from our ability to manipulate the world around us, which is an essential attribute of all living things—a defining trait of life itself. By extension, an x-ray portrait of a massive black hole at the heart of the Milky Way can be just as subjectively exciting as, say, a photograph of Angkor Wat.

One of the great challenges for us as modern humans is to reject the widespread misconception that technological perception is somehow inert, disconnected from life, or even fake. We need to open our hearts as well as our minds to a great wonder: Evolution has given us the tools to expand on our biology and to go beyond the senses we are born with.

Technology is a part of who we are. A cow is not a cow the first time a child sees it; meaning comes only through understanding. The same is just as true for an image of the Milky Way’s black hole from the Event Horizon Telescope, or for any of the myriad of other images created using our extended senses. Once we add understanding into the mix, these images overflow with beauty and grandeur.

This is why I am so excited by the invisible universe, and why I’ve become obsessed with sharing that excitement. We can all experience the other prospects on life that Thoreau imagined only as an unattainable goal. Using his terms, our technology allows us to visit the various mansions of the universe, and to look out at the cosmos through eyes other than our own.

The invisible universe is spread out before us. As a species, we have realized Thoreau’s miracle. Now it is up to each of us to stretch out our extended senses and experience it.