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The Time I Invented Astronomy at the Local Pool

Jim Hohenbary


Swimming Habits

I usually go after dark when I swim at my local health club.  I go late so that I can count on finding an open lane. I do not have good technique, and no serious swimmer would ever want to share a lane with me, so I try to oblige by staying out of the way.

However, I make an exception to my routine on Saturday afternoons. That time reliably offers open lanes for the marginally competent. These Saturday sessions are my favorite. Mostly due to the addition of sunlight. A large window covers the center of the western wall, and as the sun descends toward the top of the trees at the edge of the property, a square of golden sunlight intersects a particular section of the pool.

Sloshing through that slashing column of light makes swimming feel a little more like flying. I can feel myself manufacturing Vitamin D. It brings visual interest to the submarine blue.

This past winter, that ray of light illuminated the surface of the water at three or four in the afternoon. I would time my visits accordingly. However, one weekend as spring crept into view, I showed up at the usual time after missing several weeks. To my annoyance, no sunlight played across the surface of the water. My patch of light was still crawling across the tile floor. It was annoying. It only reached the water for a few minutes at the very end of my workout. This trend continued from week to week. I needed to swim longer or show up later if I hoped to enjoy my sunbeam at all.

Even as I adapted, I also noticed that its relative position was changing. It was moving through space as well as time. Of course, I knew that I was seeing the sun moving across the sky with the changing seasons. I also saw that the effect was easier to detect because I was returning to the pool at weekly intervals like some sort of time-lapse photographer.

Recreational Time Travel

I enjoy swimming more when I can find something to think about while I swim. One afternoon, I began to wonder if these positional changes would have been harder to notice in days long past. If the lengthening of the days would still be detectable in the time before horology (the science of making timepieces). On the one hand, we possess an innate ability to sense the passage of time. I usually start to get worried about the tater tots before my oven timer goes off. I can approximate how long it takes for the hot water to reach the shower head.

On the other hand, when you are immersed in the moment from dawn until dusk, without reference to a watch or clock or a special candle, how would you tell for certain? You might notice that the days seem shorter when it gets cold outside. But how would you prove it? Our perception of time is trickier on longer timelines. Time can go slower when you are bored. It can move incredibly fast when “flow” has sucked you into a project.

As I rolled into a backstroke, or what I like to call a backstroke, I began to imagine myself in prehistoric times. I had noticed the change in sunlight because I repeatedly returned to the swimming pool. It dawned on me that noticing any sort of celestial change back then would have probably required regular visitation to a place. A fixed point in space.

The View from Sunset Ridge

Let me introduce you to Prehistoric Jim. He does not have Fortnite or Twitter and has found a favorite spot for watching the sunset instead. He has a favorite boulder just a short walk from his village. Sitting there one evening, Jim is smitten by how the setting sun fits perfectly between the edges of two distant mesas. He returns at intervals to enjoy the same spectacle. And then a few weeks later, as insects pulse the air around him, as the rock beneath him slowly releases the heat it has stored during the day, Jim notices that the sun is no longer centered between those two distant rocks. It has started to sink behind one of the mesas instead. 

“What the heck?” Jim whispers.

He quickly checks the soil around the boulder and sees no evidence of tampering. He rules out pranksters. He then wonders if perhaps the sun itself has been drifting in its course. He has access to a lot of rocks (this being the Stone Age) and decides to set down a small stone marker where the lowest tangent of the setting sun kisses the horizon. Recalling his first visit to the spot, he might also set a second stone where the sunset touched down during his initial visit, the midpoint between those two mesas. Of course, both marker stones would be aligned relative to his boulder chair.

When Prehistoric Jim returns a week or two later (even though weeks have not been invented yet) he observes a clear linear progression. “The sun is moving. I wonder how far this line will go?” he muses and, as Thus Spake Zarathustra pounds in the background, he decides to lay down a third stone. He starts to wonder if the setting sun will circle the entire horizon, completely forgetting the fact that he has never once seen a sunset on the opposite side of the village. Nevertheless, despite his propensity for faulty hypotheses, he continues to set down stones at regular intervals. His experiment has begun.

Quick Results

Flush with excitement, I stopped at the edge of the pool to fetch my mask and snorkel. My primitive avatar was making striking progress and making my swim go much faster. “Flow” in action. I put my head back in the water and pushed off from the side of the pool. 

Prehistoric Jim is completely nonplussed when his line of markers starts to shift back in the other direction. It strongly motivates him to continue the experiment. He is suddenly on track to establish the seasonal movement of the sun, with pretty good precision, in just a couple of years, with relatively minimal effort.

I swam through the illuminated patch in the pool. My mask allowed me to see the sun filtering through to the bottom. Meanwhile, Prehistoric Jim has started to lay down a stone every night, instead of just at intervals. He establishes the length of the solar year by the time he covers the full range of motion, whether he has invented a counting system yet or not.

He only needs a few years to verify his measurements and establish a convincing oral history of seasonal correlation. “It was also pretty cold the last time we reached this particular rock!” And at some point, he starts to wonder if the sunrise follows a similar pattern. His nephew is an early riser. Jim recruits Prehistoric Isaac to track the dawn on the other side of the village. They begin to compare.

And just like that, only five or six years into the experiment, they start to establish patterns for both the sunrise and sunset. They begin to mark those patterns in the landscape. They begin to see the potential for using this information to predict seasonal weather patterns and guide farming decisions. “We decided to use black stones every time it rained, and you had better take a look at this!”

And yes, I am saying “we” because Prehistoric Isaac deserves a lot of credit for dragging himself out of bed before dawn every morning. “You know, if we play this thing right, we might become shamans!” Jim assures him. “Does this boulder look sacred to you?”

The Curiosity Constant

By the end of my swim, I felt confident that further refinements would come quickly once those first changes in the heavens were noted and recorded in some durable fashion. Lay down some bigger stones, start marking on them, etc. How much of a leap would it have been to also wonder about the moon as well, to consider the arc of the sun from dawn until dusk, to notice the nightly movement of the stars and seek more patterns? I have a niece who likes to stay up late. “Should we franchise?” the one shaman says to the other.

The number of ancient monuments and markers that are aligned with solstices and equinoxes, the multiple architectures that encode astronomical knowledge, tells a story of achievement: Chaco Canyon, Newgrange, the Great Pyramids, Serpent Mound, Stonehenge, Chichen Itza and many more. It urges humility regarding the ways in which we think our knowledge exceeds that of previous ages. However, as I dried off in the locker room, I considered that creating celestial knowledge also seemed totally possible. Exactly the kind of thing that humans could repeatedly invent and refine in different parts of the world. It seems within the reach of curious minds.

And yet, ancient alien astronaut theories seem to be more popular than ever in seeking to explain ancient monuments and ancient knowledge. So strange. Why credit this ancestral work to extraterrestrial intervention? Are we so distracted that we underestimate the power of observation? Are we so mediated that learning directly from the natural world (instead of a book or screen) seems unimaginable?

The knowledge attained by ancient civilizations impresses me. It genuinely does. However, I think it is important to emphasize that “impressive” still comfortably overlaps the Venn diagram for “possible.” We have no need to solicit paranormal explanations or to call down the machinery of the gods to explain their accomplishments, no more than we need such things to explain our own present accomplishments. In fact, we demean their legacy by doing so. 

We only need to assume that, then as now, they were capable of asking quirky questions and developing odd obsessions. We only need to assume that Prehistoric Jim and his relatives were capable of observation and curiosity, persistence and creativity.

After all, I invented astronomy from scratch in just one afternoon, and I did it wearing a pair of swim trunks.


Jim Hohenbary currently (and for the last 30 years) lives in Manhattan, KS. When he is not swimming, he works for the University Honors Program at Kansas State University. In addition to writing essays and short fiction, he has also published one novel, Before the Ruins (Blueberry Lane Books), and has recently completed the manuscript for a second. While doing research for the debut novel, Jim visited many Puebloan sites in the American southwest, an experience that particularly helped cultivate the archaeological interest reflected in this essay.

X: @hohenbary
Website: www.jimhohenbary.com


Featured photo by Matheus Bertelli (Pexels)

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