The two-part  Chaco Canyon Astronomy (on 1/26 and 1/27) was well received by the DKos community. Thank you! There were also many commentators who mentioned an interest in learning more about this fascinating subject, archeoastronmy. Some even mentioned there were many other Native American archeoastronomy sites in North America. True enough. My focus in the Chaco Canyon series, however, was to draw attention to the Four Corners region most famous archeoastronmy site, if not the most famous in the world.

In this special three-part series, a more in-depth explanation is presented. True, the facts can be applied more universally, however, I wrote these diaries in the context of a more complete explanation about Chaco Canyon's previous diaries. Nevertheless, the operative word here is "universally."

Keep the photographic images in mind as we explore the intricacies of archeoastronomy's science––and I do mean science in the strictest or loosest sense because what prehistoric people accomplished centuries ago by reading the script of the cosmos was precise. . .a precise science based on astute stellar observations, and mostly entailing tracking the pathway of the sun and moon across the heavens. These people found a way to build a bridge from the temporal to the eternal, and they planned their lives around both. The basis of archeoastronomy was to pinpoint the timing of the winter and summer solstices, as well as the spring and autumn equinox. Thus dividing the year into four precise intervals, each season celebrated for a different reason.

I hope you find these three back-to-back diaries interesting. We are going back centuries ago and you will not need so much as a clock or a calendar. Indeed, everything necessary can be found in the stars, images pecked or painted into rocks, and precise alignment of observation stations or dwellings.

(Continues after the fold.)

Think of yourself as a time traveler about to do what the likes of Dr. Who and other could do (if only).

This might do, as well, only put 'er in reverse:

Ah, here's an idea from the old Star Trek series. . .

But imagination also works wonders (yet with no contrivances necessary to do
it. . .just mental stimulus). . .

What we are going to see and think about in this opening diary is an important ceremony at Chaco Canyon. We are close enough to hear the words of some of the people gathered around an important glyph inscribed in the sandstone wall, though the language is unintelligible to our ears. Still, we know something momentous is about to happen. We can sense this in their body language and expressions; we hear it in their terse communication among each other, almost an anticipated elation that these gatherers have been waiting for.

They have even depicted their relationship with the cosmos in a variety of ways. Like this:

Given whatever is about to happen, an accurately predictable celestial event of great importance, let us step out of our minds in a manner of speaking and meld with their mind-set. The following photos liberated from the Web will also depict a story of crucial changes of seasons that correlate to this literal show and tell presentation that begins the diary. After this makeshift powerpoint photo series the explanation in the text will cover all the details insinuated by these pictures. Thus your questions will be answered further along in these twin diaries.

A Brief Background Of Archaeoastronomy: Add to the above Four Corners map the additional and better know archeoastronomy sites in this vast territory:

     • Mesa Verde (Cortez, CO)
     • Casa Grande, New Mexico (Pinal County, between Phoenix and Tucson)
     • Casa Malpaís Springerdale, AZ)
     • Wupatki (near Flagstaff, AZ)

Others famous archeoastronomy sites are mentioned below.

The term archaeoastronomy was first used by Elizabeth Chesley Baity in 1973, but as a topic of study it may be much older, depending on how archaeoastronomy is defined. Others state that Heinrich Nissen, working in the mid-19th Century was arguably the first archaeoastronomer. So could Norman Lockyer, who was working in the late 19th and early 20th centuries, and arguably can be called the father of archaeoastronomy. Still others would place the origin even later, say, Alexander Thom, whose archeoastronomy work in Britain between the 1930s and the 1970s is also renown.

Actually, the founders of archeoastronomy are prehistoric people from all over the world. After all, they just didn't stumble upon this precise and predictive science relative to the four essential seasonal shifts. These people were astute observers of the cosmos and it took intellect, practice and patience to get the knowledge necessary to know when each solstice or equinox changed.

North America has an abundance of archeoastronomy sites beyond the axis of the Four Corners Region, and the same can be said for Canada. Beyond the North American continent a litany of sites are also well established in the throes of history. For instance. . .

     • El Castillo, also known as Kukulcán's Pyramid (built in the center of Mayan center
       of Chichen Itza (Caracol) in Mexico.
     • Newgrange (passage tomb in Ireland)
     • Forbidden City in Beijing, China
     • The Andes and the Inca Empire(at Cusco)
     • Maeshowe (Mainland of Orkne)
     • Uxmal (Mayan city in the Puuc Hills of Yucatán, Mexico)
     • Stonehenge, England

There are many others around the world but these above mentioned and relative few are the more outstanding.

Today, the science of archaeoastronomy studies these archeological and significant global sites. In North America, one of the most famous sites is the Sun Dagger of Chaco Canyon. These inhabitants constructed the site over a thousand years ago and used its precise prediction for the obvious, namely predicting the changing light according to the season. Although today have calendars to tell us the date broken down into months, weeks and days, for Chacoans and all other ancient civilizations the timing of the season came from the heavens. It was therefore up to humans to figure a way to predict the timing. Chaco is also a good place to begin this diary's offering, since it is the most familiar to me and closest to home where I live. Indeed, one of Chaco's glyphs is conceivably the most famous on the planet, the Sun Dagger depicting (in other words) a precise solstice event:

The Magnitude Of Cyclical Time: A guiding force in these ancient practiced studies of the cosmos was knowing when the longest or shortest day of the year occurred or when the important spring and autumn seasons began. For the Ancestral Puebloans culture, their was a basic science concerned with temporality and the eternal, and was advanced enough to shape their culture from being merely prehistoric people relegated to elementary thinking and practices. Indeed, they were more sophisticated than some modern people give them credit for. They were also a people who lived from season to season and not just surviving on a day-to-day basis.

Besides a highly developed religious mindset about their lives and customs (or metaphysical if one prefers using this term in lieu of a religious motif), knowledge of what the stars or moon predict, and perhaps possessing an understanding of the five known and visible planets in that era, the cosmos prepared them for what they had to know about ordinary and important social events, which mainly centered on hunting and gathering, planting and harvesting. The trick, of course, was perceiving the orbiting celestial objects from the stationary starry background.

And then following the relatively closer objects transitioning in the night sky:

Yet the preciseness necessary to predict certain events, even lunar eclipses, wasn’t merely based on observations of celestial events or bodies. Rather, those priests, or by any similar title of higher office, who were in charge of such events used cyclical celestial movements to interpret the fate of their society, or so one assumes such a relied upon skill and practice was in force. Like many Puebloans today, the Ancestral Puebloans believed time was cyclical, and therefore predictable. Since the fate of the people was equally tied to these celestial movements, then it must be foreseeable as well. For them, as well as for most prehistoric and historic cultures on the planet, the most significant points of reference during the solar year came down to the solstices and equinoxes, and predicting such timely and repetitive events. Here we find the crux of their cosmology and a developing culture based on the science of prediction, not guessing.

The Various Nuances Of Archaeoastronomy: Archaeoastronomy finds its basis, as a cultural utility and by means of a variety of methods. As an overall methodology, such scrutiny of the heavens seeks to uncover evidence of past practices (for instance, the disciplines of archaeology, anthropology, astronomy, statistics and probability, and history). Because these academic methods are diverse and use data from acknowledged and different sources, the problem of integrating them into a coherent argument has also been a long-term issue for archeoastronomers. Decidedly, how its regimen fills complementary niches in landscape archaeology and cognitive archaeology. Consider how material evidence and its connection to the night’s sky can reveal how a wider perspective can be integrated into beliefs about the cycles of Nature. For instance, Mayan astronomy and its relationship with agriculture is an ideal example. Other examples which have brought together ideas of cognition and landscape include studies of the cosmic order embedded in the roads of settlements. The mathematics used in constructed settlements and all that pertains to such villages is a prime example.

Archaeoastronomy can also be applied to all cultures and all time periods, regardless. The significance of the cosmos and its starry points may also vary from culture to culture. Nevertheless, there are scientific methods which can be applied across cultures when examining ancient beliefs. Specifically, finding a means to balance the social and scientific aspects of archaeoastronomy’s principles.

Observing The Clockworks Of The Universe: Our planet’s annual orbit is the master celestial clock and denotes the common benchmark of human lives throughout the year. Years are divided by seasons just as calendars are segmented by months. Mechanical and digital timepieces measure intervals that split into hours, minutes and seconds each spin of our planet on its axis (1,038 m.p.h. at the equator which decreases north or south in latitude). Yet, it’s the Earth's regular, rhythmic orbit around the sun (about 67,000 m.p.h.) that standardizes our general timeframe of reference, regardless the geographic distances separating one from another or even generational distances of separation from our ancestors. There is also a precise mathematics to how the universe works in some special ways, including our relationship to the sun, the planets and stars.

Everything relating to cosmology, whatever one makes of it from a cultural or religious perspective, relates to our planet moving through the heavens by orbiting around the sun in an elliptical circuit. This meticulous circuit also deviates less than a second from one year to the next. Our planet processes through eight significant, yet invisible, thresholds within each orbit. These spatial milestones are therefore crucial to this broad subject, archeoastronomy. Namely, how select times of the year mark the beginning, midpoint and end of each annual season. In this sense, equinoxes, solstices, and cross-quarters, which refers to a day falling approximately halfway between a solstice and equinox. These two celestial events are merely moments shared planet-wide, as defined by the planet’s tilt and the sun's position on the ecliptic along forty-five degree arcs (see below for more background).

To ancient civilizations that were interested, perhaps even entertained by the cyclical motion of the stellar bodies, the ability to fix these cusps to the nearest day was highly prized knowledge, and more than likely sacred to their culture. With modern measurements and calculators much better accuracy is possible for determining these calculated moments. Today, equinoxes and solstices have thus become little more than annotations on occasional, say, weather reports. As for cross-quarters, they are all but forgotten select days throughout the year, despite having been observed and celebrated by people for centuries. To the ancient skywatchers, they refined their systems of regulating primitive calendars. They also memorialized celestial events, both cyclical and unique. Often they relied on sunlight and shadow effects striking and passing across select targets and building designs perfectly aligned with equinox and solstice sunrises and sunsets. For some cultures, noting cross-quarters was equally important. Sometimes the celestial cycles of the moon, Venus, even Mars captivated their attention. However, knowing seasonal durations and transitions was vital to success in ways to help sustain a culture’s existence (hunting migratory prey, spawning fish, planting crops and harvesting same).

Was The Cosmology Of Ancestor Puebloans Influenced By Outsiders? The cultural and technological sophistication of these indigenous people of the Colorado Plateau (that is, by name, an indigenous and long-standing culture) is clearly reflected in their interest in astronomical orientation. Specifically, the solar and cardinal alignment of select pueblos and their respective kivas. The cultural contact with the Mesoamerican societies (the Aztec and Mayan civilizations in particular) that had studied eclipse cycles and developed complex calendric systems i the likely source of such complex teachings. Besides, the extensive trading that existed from each of these respective geo locations assumes the Chacoans, in particular, learned something in the bargain. Namely, the advanced mathematics fostered by these southern latitude people. Then again, is it not possible for different civilizations to cultivate their various intellects independently of one another? For some, this theory also holds true. Could it also be the case outside influence literally came from the outside, as in something extraterrestrial? Did ET really stop by and share his knowledge with mere mortals? It certainly is something some folks think about, I mean, given some of the strange figures depicted on some of the Southwest's glyph depictions. . .

Not having direct knowledge of the customs of the Ancestral Puebloans requires turning to their successors, the Puebloans, for key insights relative to ceremonial importance. In this case, the significance of relating cycles of the sun and moon. Thus ethnographic reports concerning the scheduling of the winter solstice ceremony indicate strong desires to have the date coincide with the full moon.

Hopis, for example, synchronized the lunar and solar cycles over two to three years in setting their ceremonial calendar. It follows their attention to the moon must have brought them close to observing the standstill cycle. Specifically, their observance of the moon’s house denoting the theoretical lunistice (i.e., the farthest point of the moon’s northing and southing in its monthly revolution) which our planetary neighbor reaches every 18.6 years. More about the lunar cycle and its importance is given below.

It should also be noted that common to many Puebloans is their view of beginning the new year with the new lunation closest to winter solstice. Frequent planting of prayer flags at full moon, especially at winter solstice, indicates the moon's significance in the Puebloan ritual life. The duality theme in their cosmology also links the sun and moon as male and female counterparts; notably the sun-father and moon-consort or sister. The Tewa Puebloan nations (Nambé Oweenge, San Ildefonso, Santa Clara and Tesuque pueblos to mention some) also view the moon as the mask of the sun. This consistent effort to seek the synchronization of lunar and solar cycles is duly noted. Regarding the findings and theories about Chaco Canyon’s celebrated Fajada Butte and its famous spiral, the highest and lowest positions of the sun and moon and the respective reflected light and shadow at the center of the spiral signifies the purpose of creating this cosmological template positioned where it is. Pinpointing a lunar standstill cycle is even more remarkable given the precise calculations necessary to note across the face of the spiral. With the possible exception of Casa Grande’s ruins (near Phoenix) we know of no other evidence of markings of the lunar standstill cycle in the Americas. Cultural scientists have searched for other possible explanations for the timing of the shadow phenomena in the culture and weather patterns, especially in Chaco. Yet, they found nothing significant in the dates when the sun reaches the important declination +18.4º; not even when climatic patterns affecting this region fail to indicate these noteworthy dates as consistent times of rain or other climatic events. The marking of declination +28.7º is also considered not relevant to the annual solar calendar. Evidence thus far points to this archaic site as a place where the cosmologically-minded Ancestors successfully integrated on one set of spirals with one set of slabs the precise cycles of the sun and moon.

Casa Grande (or what's left of this once citadel):

Biological Time: Repercussions of such precise calculations (notably, as predictions) are based in biological time, describing the natural life cycles and events of organisms dictated by the presence or absence of light. Biological time and archeoastronomy are handmaidens to their respective and specialized disciplines. Biological time is also a unifying theory that links the timing of ancient calendars with modern scientific research. Historical records equally show how the natural world is marching to an innate drumbeat that modern civilizations are just now learning to hear and discern.

While archeoastronomers have primarily focused on humankind’s interpretation of the cosmos from the perspectives of how they influenced storytelling and religion, from all the above we note how there are other important relationships between these celestial movements and the life cycles of plants and animals. Organisms also obey rhythms that are entrained by light. For instance, sunlight has the greatest influence in one sense, yet our star’s reflection off the surface of the moon is equally significant. There’s also the darkness without these forces. Some animals, especially those in the marine environment, follow lunar and tidal rhythms. Prehistoric and historic man was more cognizant of these controlling forces than we are today since he held a much closer contact with the natural world. Remember: these people were hunters, farmers, fishermen, and shepherds; their lives vitally depended on understanding how specific movements of the celestial bodies coincided with the availability of food. They also knew how to use the changing lunar cycles. Over time this understanding has been lost to succeeding generations. Most people these days don’t even plan their activities by the moon, let alone the sun, that is other than gauging the weather.

(P. S. Everything I learned about this fascinating subject, Biological Time, came from this man and his book. He was once one of my field institute students, who, I am sure, taught me more than I taught him!)

Moments In Time––The Equinox And Solstice Events: Mentioned previously were these two pivotal major celestial events, here explained in more detail. Earth orbits the sun elliptically and simultaneously spins on its axis that’s tilted relative to the plane of orbit. This science explains how different hemispheres are exposed to different amounts of sunlight throughout the year. Because the sun is our natural and sole source of light, energy and heat, the changing intensity and concentration of its rays is what makes the four seasons possible. These changing seasons denote the solstices and equinoxes––astronomical terms that relate to the earth’s tilt. The solstices are the major celestial events that mark the points at which the North and South Poles are tilted at their maximum toward or away from the sun. It’s this direction of tilt that marks the difference between the most acute daylight and nighttime hours.

Throughout the Southwest a plethora of archeological ruins reveals the ingenious ways the Ancestral Puebloans figured out how the cosmic chronometer relates to Earth’s terrestrial clock. For instance, the explicit measurement and recording of rays passing across the face of a rock panel involves calculations of the sun’s movement on select days throughout the year. Thus an accurate prediction of equinoxes and solstices. Regarding the equinoxes, the important thing to know is that both events happen at two specific moments in time. Equinoxes happen where there’s a location on the equator and the center of the sun is observed vertically overhead. Each year these prime celestial events occur on March 20 or 21 and September 22 or 23. Hence, the name "equinox" is derived from the Latin aequus (equal) and nox (night), because around the equinox the dichotomy of night and day are approximately equally long. In short, latitudes +L and - L north and south of the equator experience nights of equal length.

By comparison, a solstice is an astronomical event that also happens twice each year. Yet the term “solstice” means sun stands still. These twin benchmarks occur when the sun's apparent position in the sky reaches its northernmost or southernmost extremes. The name is derived from the Latin sol (sun) and sistere (to stand still). Thus, at the solstices the sun stands still in declination; that is, the apparent movement of the sun's path north or south of the equator seemingly comes to a stop before reversing direction. The term solstice can also be used in a broader sense, as the date (day) when this occurs. The solstices, together with the equinoxes, are connected with the changing four seasons. In some cultures they are considered to start or separate the seasons, while in others they fall nearer the middle.

The Relevance Of The Ecliptic Plane: During the year our planet completes one orbit around the sun. We therefore take note of this obvious fact as the sun moves against the background of stars throughout the year, and does so along an imaginary line which is called the ecliptic. The ecliptic also defines the plane in which our planet and most other planets orbit around the sun. The directions to the north and south ecliptic poles are at right angles to this. As a point of reference, the Zodiac is the band of constellations running along the ecliptic.

Because the orbit of the earth revolving around the sun takes 365.25 days, the axis of the planet’s rotation, which is tilted at 23.5 degrees to the line of the poles of the ecliptic, denotes the directions to the north and south celestial poles. Polaris, the famed north star, is currently a beacon showing the direction of the north celestial pole. Like a spinning top, this axis is precessing around the ecliptic pole marking a period of 26,000 years.

This brings us to the equinoxes and their more technical aspects. At the times when the sun is crossing the celestial equator, day and night are of nearly equal length at all latitudes. In March, as the sun migrates northwards along the ecliptic, the vernal equinox takes place, while in September as the sun is moving southwards it’s the autumnal equinox. The equinoxes are also the points on the celestial sphere where the ecliptic and equator cross and the vernal equinox is used as the zero point in measuring star coordinates.

Thus the vernal equinox in March defines the movement when the sun crosses the true celestial equator––the imaginary line in the sky above the equator––from south to north, which happens around March 20 or 21 of each year. For the autumnal equinox the dates are either September 21 or 22. Like the solstices, the equinoxes have everything to with our planet’s orbit around the sun. It follows there are two moments––not whole days––of the year when the sun is exactly above the equator. At these times neither pole tilts toward the sun. These moments are simply called equinoxes. Equally, and because the earth’s axis is tilted relative to its orbital plane, sometimes the northern hemisphere is tilted toward the sun and sometimes the southern hemisphere tilts toward the sun. The change isn't severe but it’s enough to cause the changing seasons throughout the year. When the north is tilting toward the sun we generally experience warmer weather in the north. Conversely, when the south is tilted toward the sun then the southern hemisphere generally experiences the warmer weather.

This diagram may make better sense of the tilt that determines the direction of sunlight in either hemisphere:

Equinoxes Falling On Different Dates: The question is often asked why do the equinoxes not always occur on the same days each year, that is, the same dates? Consider how the earth orbits the sun, not in 365 days, but an additional quarter of a day. This is the reason for adding a leap year every four years. We simply factor in another day to the calendar so that there’s not a gradual drift of date through the seasons. For the same reason the precise time of the equinoxes are not the same each year, and generally will occur about six hours later each year, with a jump of a day (backwards) on leap years.

Technically, predicting the equinoxes comes down to the scientific perspective that entails the celestial equator. This is a great circle on the imaginary celestial sphere in the same plane as the equator. The celestial sphere is, itself, an imaginary sphere of arbitrarily large radius, concentric with the earth and rotating upon the same axis. Thus all objects in the sky can be thought of as projected upon this sphere and provides a very practical tool for positional astronomy. In short, this great circle on the imaginary celestial sphere defines a projection of the terrestrial equator out into space. As a result of the earth’s axial tilt, the celestial equator is inclined by ~23.5° to the ecliptic plane.

Thus the intersection denotes 0 declination. Declination is one of the two coordinates of the equatorial coordinate system, the other being either right ascension or hour angle. Declination in astronomy is comparable to geographic latitude, but projected onto the celestial sphere. These points of intersection are called equinoctial points, the vernal point, and the autumnal point. By extension, the term equinox may also denote an equinoctial point.

It would be tempting to continue on with this engrossing subject (well, engrossing to some), but i think it as good a time and place to break it off and continue in tomorrow's second diary installment. Meanwhile, you can study what was just presented and prepare to take a test tomorrow. Just kidding. Still, there is a lot to think about, and for those of you DKos community members who have children or grandchildren, or perhaps inquisitive friends or relatives, the next time someone asks why seasons change you have a lot to tell them. You can also mention there were people long, long ago, who did exactly what we do today, that is, with our sophisticated electronics, satellites, detailed maps, clocks, and everything that makes the world go around and around in its precise affairs. Compare what we know today to the primitive tools these people used. . .and with the same precise accuracy.

A parting shot that is as archetypal as it is lovely to behold:

And to the people to whom this diary is specially dedicated:

As always, your thoughtful commentaries are welcomed.


Originally posted to richholtzin on Tue Feb 19, 2013 at 02:19 PM PST.

Also republished by SciTech and National Parks and Wildlife Refuges.

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