The Romance of Archaeoastronomy

by Dan Kutsko

The last vestiges of sunlight had long since disappeared from the western sky as the obviously official party made its way along now silent thoroughfares toward its destination on this very special of all evenings. They crossed the narrow neck of land connecting the peninsula to the mainland of Tenochtitlan, the glittering capital city of the Mexica Empire, they could not but notice that the dwellings of the people who would later be called the Aztec were dark and still -- the fires had all been extinguished and domestic utensils suck as bowls and cups and bottles and jars had been all smashed to shards during the last five days. These days marked the final days of the Mexica cosmology and the few hours remaining in this, the last day of their 52 year cosmic cycle were important in determining the future of this nation. These current rulers of the valley surrounding Lake Texcoco and the great city built on the lake kept time with two calendars -- a 365-day civil calendar and a 260-day religious calendar. The two coincided only once every 52 years, and on that day, the gods would decide whether the universe would be permitted to continue for another 52-year cycle. Hence the destruction of the household items and the extinguishing of the domestic fires -- either these things would no longer be necessary, or they could be made anew, if the new cycle was allowed. It would be bad luck to start a new era with old crockware and fire. So for the previous five days this orgy of domestic vandalism proceeded, finishing only at sunset of this, the last day.

As the little procession continued, the path rose toward a small hill at the edge of the peninsula which would be called by others the "Hill of the Star." Here, a stone platform and altar had been erected and here the group stopped. Aside from the late autumn breeze which ruffled their feathered cloaks and rippled the lake waters, the most obvious sight was the blazing panorama of the heavens and, to the trained eye, the small irregular grouping of stars which they called Tianquiztli -- today, we call them the Pleiades -- slowly climbing up from the east toward the top of the sky, toward the top of the world axis. Four times previously the gods had decided to terminate their experiment with mortals, having destroyed mankind by hurricanes, conflagration, floods and, curiously, by having all humans eaten by jaguars. This current era was the fifth "sun"and was subject to renewal on this very night.

To the priests in the group, when the Pleiades reached zenith as they crossed the meridian, the sun would be at nadir and the future of the Mexica would hang in the balance. To hedge their bets with the gods, a possibly willing sacrificial victim accompanied them. At the appropriate time, his chest would be laid open with an obsidian knife, the heart excised and a small pile of kindling would be inserted into the gaping wound. If the head priest managed to light a fire in the oozing cavity and the Pleiades continued on past the zenith, then a new 52-year contract was assured with the gods. The flame was carried to the temple of the sun god, Huitzilopochtli, and the torches lit from the fire were used to re-light all the fires of the city, just as the sun, buried below, was re-lit and moved toward the new era's first dawn.

As the now joyous procession returned to the Templo de Mayor, the first murmurings of the reborn nation could be sensed as the city began to come to life again. With the traditional 2-week celebration before them, their thoughts may not have included the one who did not make the return journey with them, whose sacrifice had assured their survival and that of the Mexica.

Archaeoastronomy is that amalgam of astronomy, archaeology and anthropology that deals with the interest shown by all peoples of all ages in the sky and the things that go on there. Prehistoric hunters or ancient farmers, warrior tribes or nomadic herders -- they all used the sky and its language to order their existence and provide answers to the big questions. The sky and what it's made up of, what it means and what makes it go, have always been at the heart the advancement of human thought and the origin of all science.

Of all the sciences, archaeoastronomy is easily the most subjective. Drawing as it does from all human endeavor, it is genuinely multi- and interdisciplinary. While its canon is solidly based on positional astronomy and spherical trigonometry, the interpretations that result are often varied and confusing. As such, archaeo-astronomy has an adventurous and exciting aura that is often characteristic of cutting edge explorations and there is a certain romantic element, in the literary sense, associated with excavating and surveying a site that is hard to approach in this day of bland-sounding discover-ies in the so-called "hard"sciences. The appeal of this type of material to high school students should not be overlooked by the creative teacher who is interested in giving his students a worthwhile and memorable learning experience that is both "hands-on" and, perhaps, more importantly, "brains-on." This is the kind of thing that kids remember long after they've graduated and it almost always works because the sky almost always works as advertised.

Given the nature of the information available, only the simplest, most obvious and most readily observable phenomena need be considered by students. Even though the school year is shorter than a solar year, annual celestial occurrences are not out of the question. An adequate foundation for an understanding of the level of astronomical and calendric sophistication of "ancient"skywatchers can be had through the simple expedient of observing such commonplace celestial events and sunrise and sunset, moonrise and moonset and the rising and setting of several easily observed and identified naked-eye stars. The results of carefully crafted activities can be highly educational and motivational as well a being profoundly gratifying to student and teacher alike. Something as simple as observing the motion of the shadow of a stick over the duration of a single class period can elicit expressions of delight and awe from even the most jaded members of a class. And when they are led to the realization that they can, by using this simple <clock,= determine the actual length of the solar day, accurate down to the minute, one can almost feel the thrill that accompanies their dawning awareness of this connection, this oneness with the heavens.

Near the 10,000 foot summit of Medicine Mountain in northern Wyoming's Big Horn Range, the winds blow powerfully and constantly. The Lakota shamans huddled in the pre-dawn twilight waiting -- waiting for the event that will mark the final, gentle warning to return to the verdant valleys almost two miles below. If they were not so intent on watching the eastern horizon, they might have taken note that the rising sun had already touched with fire the peaks a hundred miles to the west--peaks that formed part of the boundary of the sacred ground that would, two millennia in the future, be called Yellowstone. They had spent the last three months on this holy mountain, ever since the snows from the last winter receded from the passes and allowed them access to this windswept shoulder of barren rock. Here, untold ages before, other Lakota had set a ninety-foot circle of stones. They sat with their backs to the west and their eyes sighting across the central hub and along one of the 28 spokes radiating outward to one of six cairns punctu-ating the circumference of the ring. What rites they performed and what liturgies they recited would perhaps never be known -- nor would their motives. This site was chosen because of its utter magnificence and its utter isolation, and for whatever reasons these medicine-men were drawn here, it was time to leave. The snows would return -- soon. The stars told them so.

Huddled in this lonely high church, the priests awaited the appearance over the appointed cairn of the brightest star in the heavens, Sirius, in the instant before the brilliance of the rising sun washed the sky clean of all heavenly bodies but itself. Twenty-eight days previously, the star Rigel had appeared similarly over the cairn to the left and 28 days prior to that, Aldebaran had risen over another cairn on the very day of the summer solstice. But it was the appearance of Sirius in the pre-dawn half-light that sent these men away from this magnificent and ascetic isolation and the great power of place that can be sensed there even now, twenty centuries removed.

A shadow stick, or gnomon, and a period of time -- the longer the better -- are all that is really necessary for a simple demonstration of the skills of our precursors. The power they held over their societies and even over their rulers was due to their demonstrated knowledge of the skies. This, and the predictions they were able to make, showed the shamans as coversant with the gods.

A permanent gnomon -- a flagpole would be ideal -- and some method of marking the progress of the shadow are tools. The marking should last at least six months. The students simply need to mark the position of the shadow of, say, the globe or eagle at the top of the pole. This would be done every weather-permitting day for the entire school year, if possible. Ideally the autumnal and vernal equinoxes should be included. An analysis of the resulting pattern should reveal much about the niceties of the earth revolution as seen throught the sun's trip through the zodiac. The more carefully the data is recorded, the more readily the students might be led to make predictions as to the nature of the remainder of the pattern. The sense of satis-faction and accomplishment experienced by students involved in an exercise like this is surprising and uplifting for everyone involved.

Dan Kutsko teaches high school in Houston, Texas. He has participated in excavations and sightings at a Zapotec site in Monte Alban, Mexico, and analyzed alignments of burial mounds in Senegal.

Further links:

The SHiPS Teachers' Network helps teachers share experiences and resources for integrating history, philosophy and sociology of science in the the science classroom.