2011 Landscape as Lens: Understanding Hopewell Eclipse Prediction Capabilities at the Newark Earthworks

This paper was written with the intention of submitting it to Hopewell Culture National Historical Park, for their online newsletter, Hopewell Archaeology. The paper is written for general readers. It was compiled in Carbondale, IL in 2011, using ESRI ArcMap GIS software.

Landscape as Lens: Understanding Hopewell

Eclipse Prediction Capabilities at the Newark Earthworks

Christopher S. Turner

2011

The Hopewell geometric enclosures have long fascinated anthropologists and lay folk alike. Since the early 1980s, researchers have suggested that these large earthworks may have functioned as sighting devices designed to monitor sunrises and moonrises. With regard to sunrises, it can be demonstrated that any resultant calendrical knowledge would have contributed to the accurate timing of the planting and harvesting of food crops, what anthropologists call “subsistence scheduling." Less apparent is the role that the monitoring of moonrises may have played.

Ray Hively and Robert Horn of Earlham College in Richmond, Indiana have written several papers concerning the use of the Hopewell earthworks and their ability to delineate various moonrises along the horizon (Hively and Horn 1982, 1984). Especially interesting is their research regarding the octagonal shaped enclosure in Newark, Ohio (Figure 1). They discovered that the octagon marks the various rise and set points of the moon as manifested during its 18.6 year cycle. Because the lunar orbit is tilted five degrees relative to the earth’s orbit around the sun, its extreme positions along the horizon differ from those of the annual movement of the sun between summer and winter solstice. Additionally, the lunar orbit wobbles or precesses in a period of 18.6 years. What this means in effect is that the moon’s extreme rise and set points along the horizon differ from those of the sun. The moon reaches these extreme locations only for relatively brief intervals twice every 18.6 years. Hively and Horn demonstrated that the Newark Octagon earthwork indexes these extreme lunar rise and set points, which are called the lunar extrema or lunar standstills.

In 2006, the researchers from Earlham College published a statistical analysis of their earlier work. They found that the assortment of calendrical sightlines at the Newark Octagon would not occur randomly except in very rare cases. This statistical evidence creates a strong argument that the lunar angles evidenced at the octagon were intentionally encoded by the Hopewell who built the enclosure some seventeen or eighteen centuries ago.

The members of Hopewell society who designed this and the other geometrical mounds that were used to monitor the heavens were likely to have been elite individuals among their people. Anthropologists refer to those who possessed such esoteric knowledge as calendrical specialists. These elite members of Hopewellian society would have been accorded special status, and they likely had the ability to organize the large parties of workers that would have been needed to construct the massive earthworks. The question arises, just how did they gain their elite status?

The current archaeological record suggests that the Hopewell were involved in raising various plant foods that contributed in part to their overall diet. Paleobotanists refer to these various seeds and the plants that they came from as the Eastern Agricultural Complex (Smith 1995, Wymer 1997). As evidenced in the archaeological record, the use of these cultivated foods increased in the same era as when the large enclosures appeared (Case and Carr 2008:86-88). We can assume that the elites who maintained the Hopewell calendar monitored the various sunrises in order to maximize the output of their cultivated plant foods. This much is straightforward. Less obvious is why the same specialists would be concerned with the motions of the moon, and in what manner it would add to their social status by doing so (Reyman 1987:130).

The answer may lie in the arrangement of the earthworks themselves, and in their placement on the local landscape. Studies of the landscape with regard to the siting of monuments fall under the category of phenomenology. Also called landscape archaeology, this investigative tool has been developed in Britain where there is a great array of earthen and stone monuments to be found. The lens of phenomenology is also well suited to examining the network of Hopewell geometric earthworks found in Ohio. An assessment of the earthworks in Newark  focusing on their placement across the local landscape can be offered.

First, we must examine the location of the earthworks themselves. In Newark, there are two extant large sites to consider: the Octagon Earthworks and the Fairground Circle (Figure 1). The latter is a large circular earthen enclosure with a single opening or gateway. When viewed through this singular opening from the center of the circle, the sun will rise along this sightline in early May (Turner 1982, 2004). This interval in the calendar is an ideal planting time in Ohio. There is even an old folk saying reflecting this, which says that the corn farmer will lose “A bushel a day after the eighth of May” by planting after that date. (Mike Van Dorn, personal communication 1983). To plant sooner means to risk losses due to a late freeze. Evidence of use of the early May planting index in ethnographic records of other Native American societies can be found. The Hopi Indians of Walpi Pueblo in Arizona were known to have marked this planting interval, calling it neverktcomo (Forde 1931:384-386). They called the month preceding this date “the waiting month” (hakiton muya), referring to the need to wait till the chance of a late freeze had passed (Malotki 1983:357, 374-377). Historically this calendrical division in early May is called a “cross quarter date”. This form of calendar simply divides the year into eight equal parts, instead of the four seasons that we use today. It was commonly used in Europe during the Middle Ages for instance. Our Groundhog Day and Halloween are remnant holidays from the old cross quarter calendar (McCluskey 1989).

The idea that the Fairground Circle was utilized for establishing the planting calendar is consistent with the idea that elite Hopewell specialists were regulating subsistence scheduling. But again, what advantage would be gained by these specialists in monitoring the location of the moon’s various rise and set points, the lunar extrema or standstills?

It is here that phenomenology can be useful. First, it is necessary to describe the manner in which these various calendrical sightlines function. There are three points on the landscape that must be defined.

First , the individual making the observations must stand in a particular location. In studying archaeoastronomy, we call this location the “backsight”. The backsight at the Fairground Circle is located at the Eagle Mound at the center of the great circle. At the octagon, the primary backsight is located on the southwest end of the earthwork at the so-called Observatory Mound.

Secondly, the part of the earthwork toward which the observer sights is called the “foresight”. At the Hopewell geometric earthworks, the foresights are defined by the gaps or gateways between the earthen embankments. At the Fairground site, the singular gateway or opening in the circle is the foresight (Figure 2). At the octagon, the primary sightline is defined by the gaps along the main axis of the overall earthwork. As pointed out by Hively and Horn, various combinations of other gateways located at the vertices of the octagon embankments form the backsights and foresights for the remainder of the lunar extrema sightlines that they found.

Thirdly, each of the various calendrical sightlines defined by the earthworks terminate somewhere along the surrounding horizon. These locations are called aptly enough the “horizon foresights”. It is these horizon foresight loci that are essential in understanding the overall design and placement of the earthworks on the landscape, and that give insight into their use and function.

The creation and observational use of horizon foresights can be found in many examples across cultures around the world. The Inca of Cuzco in Peru marked solar rise points using stone pillars as horizon foresights (Dearborn, Seddon, and Bauer 1998). The Hopi in Arizona indexed the various days of the year by marking where the sun would rise along the horizon. They memorized these locations and performed rituals at some of them (Stephen 1936:60, 82, map 4; Zeilik 1985:S12). In many cases, horizon foresights will occur at locations that form distinct topographical features, such as mountain peaks or gaps.

With regard to the Hopewell, it is relatively easy using modern GIS software or even topographic maps to determine the locations of the horizon foresights that are delineated by the geometric earthworks. In the case of the Fairground Circle, the sightline terminates on a bluff feature that lies three kilometers from the circle itself (Figure 3). It is worth noting that the horizon foresights suggested by the calendrical sightlines are potential locations for archaeological research. These sites can be tested for evidence of use as foresight locations. Archaeologists might expect to find evidence of burned rock indicating that fires were set to aid in visual sighting during calendrical observatrions. Or, there may be small earthworks at some of these areas. Conversely, excavation may yield evidence of ritual offerings at the various horizon foresight loci. 

The situation is similar at the Newark Octagon. Though Hively and Horn discuss the entire suite of eight lunar extrema or standstills, I will only mention the primary sightline along the main axis of the earthwork (Figure 4). This sightline terminates on a prominent hill that lies some 5.7 kilometers from the Observatory Mound (Figure 5). This location is also a prime candidate for archaeological exploration. If the lunar sightlines are valid, as the statistics suggest, then there will almost certainly be archaeological evidence of use of this horizon foresight by the Hopewell.

In examining the topographic maps, it became apparent to me that the horizon foresight for the Fairground Circle lay almost directly due east of the Observatory Mound at the Newark Octagon. In astronomical terms this means that the equinox sunrise might occur along a sightline from the Observatory Mound to the Fairground Circle horizon foresight. To answer this question, I checked the astronomical and topographic data, which confirmed my suspicion.

Again, as seen from the Observatory Mound, the sun will rise at equinox over the location that also serves as the horizon foresight for the Fairground Circle sightline (Figure 6). What does this means regarding astronomy or archaeoastronomy? In can be shown that during the 18.6 year lunar cycle eclipses can occur only at the full moon nearest equinox at the time of the lunar extrema or standstills. Thus, if a person at the Observatory Mound noted equinox sunrise over the horizon foresight to their east, and on the same day confirmed the moon rising at the lunar extrema, they would have the ability to predict an eclipse from this single backsight location. The geometry of this is inescapable.

In must be noted that this would likely apply to only lunar eclipses. Solar eclipses would occur at the new moon during these periods, but solar eclipses cover a small area of the earth’s surface, seen by comparatively few witnesses . The opposite is true of lunar eclipses. A total eclipse of the moon can be seen over more than 50% of the earth’s surface. Of course, not all lunar eclipses are total. Some are so minor that they are not visible even if you are looking directly at the moon and are expecting the eclipse (these are the penumbral lunar eclipses). 

In this regard, overall about 45% of the time, the Hopewell could actually see an eclipse predicted by a calendrical specialist. Nonetheless, this would be a significant number of successes, and the ability to predict these would likely greatly impress the Hopewell people who were made aware of the prediction. Inasmuch as elite status formation is suggested by the ability to produce an accurate planting calendar, the same might be suggested by the ability to predict the more evanescent eclipse of the moon.

If we consider the design of the Newark Octagon, it is apparent that no part of the octagonal earthwork is utilized as a foresight to mark the equinox. The equinox sightline is only indexed by the horizon foresight in question, the one shared with and defined by the Fairground Circle. It can be reasoned that the lack of any overt architecture marking the equinox sunrise line may have been intentional. This may be indicative of the effort to conceal the means by which the eclipse predictions were made. The esoteric or hidden role of calendrical knowledge can be evidenced by examples from other cultures across the ethnographic record (e.g. Reyman 1987:131).

Various researchers have recently suggested that the Newark earthwork complex may have functioned as a ritual pilgrimage center (Lepper 2006). These pilgrimage events are envisioned to have occurred at appointed times in the Hopewell calendar. It is possible that some of these gatherings may have been timed with regard to the 18.6 year lunar cycle. Eclipse prediction may have been part of the drawing effect that lured pilgrims to the site.

          Whatever the case, a considerable amount of organized labor was employed to create the earthwork assemblage that was noted by early Euro-Americans in Newark. The Octagon earthwork appears to have been the most complex and refined of all such Hopewell enclosures. It is insufficient to suggest that it was constructed with no other intent than to mark various moonrises that were otherwise without cultural significance. The demonstrable ability of these earthworks to be utilized as eclipse prediction devices may answer the “why” regarding their construction.

References Cited

Case, Troy D. and Christopher Carr

            2008    The Scioto Hopewell and Their Neighbors: Bioarchaeological Documentation and Cultural Understanding.           Springer, New York.

Dearborn, David S. P., Matthew T. Seddon, and Brian S. Bauer

1998    The Sanctuary of Titicaca: Where the Sun Returns to Earth. Latin American Antiquity 9(3):240-258.

Forde, C. Darryl

1931    Hopi Agriculture and Land Ownership. Journal of the Royal Anthropological Institute 61:357-405.

Hively, Ray  and Robert  Horn

1982    Geometry and Astronomy in Prehistoric Ohio. Archaeoastronomy supplement to the Journal for the History of Astronomy 13(4):S1-S20.

1984    Hopewellian Geometry and Astronomy at High Bank. Archaeoastronomy supplement to the Journal for the History of Astronomy 15(7):S85-S100.

2002    A Statistical Study of Lunar Alignments at the Newark Earthworks. Midcontinental Journal of Archaeology 31(2):281-322.

Lepper, Bradley T.

2006    The Great Hopewell Road and the Role of Pilgrimage in the Hopewell Interaction Sphere. In Recreating Hopewell, edited by Douglas K. Charles and Jane E. Buikstra, pages 122-133. University press of Florida, Gainesville.

McCluskey, Stephen C.

1989    The Mid-Quarter Days and the Historical Survival of British Folk Astronomy. Archaeoastronomy supplement to the Journal for the History of Astronomy 20(13):S1-S19.

Malotki, Ekkehart

1983    Hopi Time: A Linguistic Analysis of Temporal Concepts in the Hopi Language. Mouton Publishers, Berlin.

Reyman, Jonathan E.

1987    Priests, Power, and Politics: Some Implications of Socio-ceremonial Control: In Astronomy and Ceremony in the Prehistoric Southwest, edited by John B. Carlson. Maxwell Museum of Anthropology, Albuquerque.

Smith, Bruce D.

            1995    The Emergence of Agriculture. Scientific American Library, New York.

Stephen, Alexander M.

            1936    Hopi Journal. Columbia University Press, NY.

Turner, Christopher S.

1982    Hopewell Archaeoastronomy. Archaeoastronomy 5(3):9. Center for Archaeoastronomy, College Park, Maryland.

2004  Middle Woodland Archaeoastronomy in Ohio. Paper presented at the 7th Oxford International Conference on Archaeoastronomy, Flagstaff, AZ.

Van Dorn, Michael

1982    Personal communication regarding local folklore. Van Dorn is a long time resident of Newark, Ohio, and has provided the author with detailed information concerning the Hopewell earthworks.

Wymer, Dee Anne

1997    Paleoethnobotany in the Licking River Valley, Ohio: Implications for Understanding the Hopewell. In Ohio Hopewell Community Organization, edited by William S. Dancey and Paul J. Pacheco, pp. 153-171. Kent State University Press, Kent, Ohio.

Zeilik, Michael

1985   The Ethnoastronomy of the Historic Pueblos, I. Calendrical Sun Watching. Archaeoastronomy supplement to the Journal for the Histor of Astronomy, 16(8):1-24.

          

Figures

Figure 1. Fairground Circle lower center, Octagon group upper left (Squier and Davis 1848)

Figure 2. Fairground Circle lower left, with color-coded viewshed sightline, green = visible, red = invisible. Sightline terminates on bluff feature three kilometers distant, right.

Figure 3. Detail of Fairground Circle sightline horizon foresight bluff feature.

Figure 4. The Newark Octagon, primary axial sightline, color-coded for visibility

Figure 5. Detail of Newark Octagon axial sightline foresight feature.

Figure 6. Equinox sunrise as seen from the Observatory Mound at the Octagon group occurs over the same horizon foresight as seen from the Fairground Circle’s cross quarter sightline

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