Tuesday, August 15, 2017

Eclipses in the Hohokam Sky

With all this excitement over the upcoming eclipse on August 21, 2017, Museum staff began to wonder, what it would have been like for the Hohokam to see an eclipse? Would there be any evidence that they recorded these celestial events? There has to be some research out there! Right?


Pueblo Grande Museum staff did a little research of our own and...et voilĂ !

We found a research paper by Bruce W. Masse, and Fred Espenak from 2006, Sky as Environment: Solar Eclipses and Hohokam Culture Change. This paper is part of the larger publication of papers, Environmental Change and Human Adaptation in the Ancient American Southwest, from the 61st Annual Society for American Archaeology Meeting in New Orleans, LA, in 1996.

And after reaching out to our archaeology friends and colleagues, we discovered that former city of Phoenix Archaeologist, Todd Bostwick, Ph.D. had written a summary of this very paper! AND he was kind enough to share it with us, so that we could share it with you!

We figured that if we were nerdy enough to get excited about a paper that discusses how NASA software was used to track multiple celestial events that would have been witnessed by the Hohokam, such as supernovas, comets, meteors AND solar and lunar eclipses…. Then maybe others would be too!

Below is the summary by Dr. Todd Bostwick of the Masse and Espenak article with some of the tables from the Sky as Environment paper:

The Hohokam Night Sky

Our current understanding of the Hohokam night sky can be aided by computer programs that reconstruct major celestial events for a particular period of time. Masse and Espenak (2006) have identified a number of celestial events that the Hohokam witnessed during their reign in the Sonoran Desert. These include supernova, comets, meteors, planetary conjunctions of planets visible to the naked eye (Venus, Jupiter, Saturn, Mars, and Mercury), and solar and lunar eclipses. 

The Hohokam would have seen a series of meteor storms between A.D. 800 and 940, and Masse and Espenak (2006:275) propose that the use of repeated starlike elements on Hohokam pottery during the Colonial period may record impressions left by those meteors. During the eleventh century, two major supernova occurred in the Hohokam night sky—the Lupus supernova of A.D. 1006 and the Crab supernova of A.D. 1054. In addition, as many as 900 comets would have passed through the night, including Halley’s comet in A.D. 1066. Some of these comets would have looked like horned or feathered serpents, perhaps providing inspiration for pottery and rock art images. 

Possibly most influential on the Hohokam were solar eclipses, when the Sun suddenly disappears during the day. Although short in duration, solar eclipses are known to cause animals to become silent and confused, flowers to close, unusual gusts of wind, and Venus and Jupiter to appear in the sky during the day. Utilizing software developed by Fred Espenak for the National Aeronautics and Space Administration (http://eclipse.gsfc.nasa.gov/eclipse.html) and other astronomy programs, Masse and Espenak (2006) reconstructed the times and locations of all solar eclipses that occurred in the Hohokam territory. The first total solar eclipse to be seen by most Hohokam took place in A.D. 736, followed by another one 61 years later (A.D. 797). Total eclipses also occurred in A.D. 1076 and 1379. Masse and Espenak (2006) argue that these four solar eclipses had profound effects on the Hohokam, ushering in changes in their society and material culture. 
The eclipse of A.D. 797 occurred only a few years before the huge floods of A.D. 803–805, and both of these events coincide with the introduction of the ritual ballgame to the Hohokam from southern groups, possibly “to prevent further occurrences of both solar eclipses and floods” (Masse and Espenak 2006:262). The eclipse of A.D. 1076 is associated with the abandonment of Snaketown (upon which the eclipse path was centered) and other important villages, leading to the reorganization of the Hohokam during the Classic period. The Hohokam ballcourt system declined regionwide soon after Snaketown’s demise. The total solar eclipse of A.D. 1379 took place only a few years before the major floods of A.D. 1381–1384. Archaeologists currently think that these floods, combined with droughts and social upheaval, brought about the collapse of the Hohokam culture.

An O’odham story about the destruction of the Hohokam villages mentions that Elder Brother, while sitting beside the Casa Grande Big House, made the Sun and Moon stand still (Bahr 2001:45). Masse and Espenak suggest this may have been a cultural encoding of the solar eclipse of A.D. 1379, a “clarion call to assemble the armies to overthrow the Hohokam” (2006:272). Casa Grande is located in the center of the eclipse path, a location in which the physical effects of an eclipse are most noticeable. Although we will never know for certain if the solar eclipses were directly responsible for changes in Hohokam society, it is likely that they were considered highly significant events that brought great concern to Hohokam sky watchers and village leaders.

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