The history of astronomy can be read as a story of better and better vision. Over the centuries, we have supplemented our vision with technology that allows us to see further and more clearly; while Ancient astronomers, who relied only on their naked eyes to perceive the universe, managed to make star catalogues and predict comets, Galileo, pressing his to a telescope, saw all the way to the moons of Jupiter.
Optical telescopes and the human eye are fundamentally limited; early astronomers were forced to gaze into telescopes for hours on end, waiting for moments of visual stillness long enough to allow them to quickly sketch drawings of the features they were simultaneously trying to understand. Between a telescope (incidentally, “telescope” is Greek for “far-seeing”) and the celestial bodies beyond, the Earth’s atmosphere itself is in turbulence, the optical refractive index bleary—which presented early astronomers with a view of the universe that was blurred, twinkling, always in flux. This is because the sky is not transparent. Thermal currents passing through the Earth’s atmosphere cause air density (and hence the refractive index of air) to vary, to warble like a desert mirage. Light does not pass through this unaffected. Quite the opposite, in fact—thermal currents are like thousands of lenses floating around in the air. We call this phenomenon “astronomical seeing,” and it’s why stars sparkle, why even the moon seems to be swimming in water when peered at through an optical telescope.
It wasn’t long before Galileo and his fellows had seen as far as their technology—and their vision—could reach. In the years to follow, new far-seeing tools popped up as needed: X-ray telescopes, gamma ray telescopes, high-energy particle telescopes, even telescopes floating in space. As time progressed and our science grew more refined, we tried wavelengths previously unnoticed; we paid attention to new qualities; when we thought we’d seen it all, we looked again, our vision evolving beyond biology as we began to “see” with technology.
The inevitable result was that though the physical universe never changed, we did, because we looked differently.
This different-looking triggered perhaps the most important conceptual leap in the science of the 20th century: the realization that there is more to reality to what can be seen. The years between 1880 and 1930 saw massive upheavals in the way science was conducted—during this period, we moved from the strict empiricism of Newton to the reliance on unobservable and theoretical constructs that dominates the discipline today. We began to peer into previously unseen worlds; we parsed the structure of the atom and discovered elementary particles. Once we were there, our physics no longer had bearing. We needed to invent and codify new ways of seeing, ways not dictated by observable phenomena; and so our understanding of time and space gave way to general and special relativity, quantum mechanics, and alternative geometries. The intellectual legacy of this radical change—and its relevance to my point here—is in the primacy it lends to subjectivity, to not only the instruments of seeing, but those who peer into them.
Astronomy, too, zygoted in the early 20th century. Photography solved the problem of hand-drawing findings between patches of blurry sky. Infrared, radio, X-ray, and finally gamma-ray astronomy came to prominence, filling our coffers with surreal images of a previously invisible world. We used spectroscopy to study stars; our sun was found to be part of a galaxy, and the existence of other galaxies was settled by the great Edwin Hubble, who identified many others, rapidly receding from our own, at impossibly large distances. We created the model of the Big Bang. We stumbled upon cosmic microwave background radiation. All of a sudden, the story of the universe as we knew it vaulted out of the visual world and into a rich and million years-long narrative of unseen forces and galaxies so distant they bordered on theoretical abstractions. Like science itself, visual perception of the cosmos evolved from the physical to the theoretical; when we speak of “seeing” astronomical images, we’re talking about a highly mediated experience, captured by mechanical sensing devices, where invisible qualities are color-coded into something the human eye can register as information.
The eye is almost universally a symbol of intellectual perception; in Taoism, in Shinto, in the Bhagavad Gītā, the eyes are the sun and moon. Is it any wonder that the ancients conflated astronomy and astrology? That those who look out at the universe have so often been mystics, seekers, and seers? We speak of “visionaries” in all fields as people who are capable of seeing furthest—beyond the blurred intermediary of the physical world and straight to the heavens.
This article was originally published at Universe on ScienceBlogs.com.
To learn how scientists are now using gravity waves instead of light to peer deep into the cosmos with the cutting-edge LIGO project, check out Astronomy’s New Messengers and the accompanying Shorts now on WSFtv