House of the Great Kiva: Astronomical Observations

By Tom Orbesen

Standing in the altar room looking out through the east-facing door towards the dark mesas, I could tell that the sun was about to rise. On this summer solstice morning the sky was streaked with red and yellow clouds. A halo of light formed behind the mesas, and then an arc of brilliant, blinding light peaked over the mesa tops. As the world slowly turned, I watched the ancient sun-god rise above the House of the Great Kiva.

There are many ruins in northwestern New Mexico and the surrounding Four Comers region, perhaps none as spectacular and mysterious as the House of the Great Kiva located at Aztec Ruin National Monument near the city of Aztec, New Mexico. It was originally constructed about 1115 A.D. by the Chaco people, a branch of the Anasazi culture. An outgrowth of their cosmic religious tradition was the use of solstice diagonals and equinox bearings in the construction of various religious buildings. Earl Morris, the noted Southwestern archaeologist who excavated the Great Kiva in 1921, described it as the center of highest knowledge then known to the Chacoans.

The Pueblo Indians of Arizona and New Mexico are thought to be the descendants of the ancient Anasazi. Through the study of Pueblo Indian ethnology, researchers can sometimes gain insights into rites and rituals that the Anasazi might have engaged in. The Pueblo Indians often conduct ceremonies centered around the winter and summer solstice periods. At the winter solstice in the northern hemisphere, which occurs approximately December 21, the sun is at the southern limit of its travel through the sky. During the summer solstice (around June 21), the sun is at its most northern limit of the year. At the solstice — the word literally means "sun stands still" — the sun appears to stand still for several days at its rise and set points. These solar events provide ceremonial, calendrical, and symbolical times of importance for the Pueblo Indians. Their ancestors, the prehistoric Anasazi, may have participated in similar events.

At the House of the Great Kiva, during the time of the summer solstice, the rising sun's first light beams through the door of the altar room which creates a bright door-shaped rectangle on the west wall. A Sun Priest* behind the altar would have been illuminated by the sunrise of the summer solstice. Down in the chamber of the kiva it is still dark. Shortly afterward, a shaft of light beams through the door of the peripheral room and another door-shaped rectangle of light appears on the west wall, next to a door that the Anasazi had constructed. In the dark chamber of the Great Kiva, past centuries of knowledge may have been revealed by the power that the Sun Priest seemingly held over the creative force of the Anasazi world — the sun.

* As it is used in this article the term "Sun Priest" is a generic term. Other clan elders of the Anasazi may have also stood behind the altar and performed similar duties inside the Great Kiva.

Just before the sun sets behind the ruins, the sunlight passes through the door of the northwest peripheral room located next to the altar room. In Pueblo Indian ethnology, the center of cardinal and intercardinal directions is a place of mystery and reverence. For a visual effect, the Sun Priest might have stood in the approximate center of the Great Kiva and been illuminated by the setting sun's light. The center of a cosmic structure like the House of the Great Kiva unquestionably had great religious importance for the Anasazi.

The autumnal and vernal equinoxes may have also provided the Chacoans with ceremonial and calendrical opportunities. In addition, the rising sun of the equinox may have provided a bearing for construction purposes. At the time of the equinox, the light of the rising sun passes through the door of the peripheral room* and strikes the west wall. In so doing, the light splits and casts a shaft of light on the northeast pillar. Whether this was done intentionally by the Anasazi is not known: there may have been some fault with the restoration, or it might have been a sophisticated interaction of light with an internal feature of the Great Kiva whose function is as yet unknown.

* The original diagram drawn by Earl Morris shows a wall that would have blocked the rising sunlight of the equinox from entering the Great Kiva. However, when Earl Morris restored the Great Kiva in 1934 this wall was not restored (indicated by dotted lines on the drawing). It is thought to be a feature of the Mesa Verde people who occupied the Great Kiva after the original builders had left. The wall was not part of the original Chacoan construction, and during Chacoan occupation the light from the rising sun of the equinox would have been seen inside the Great Kiva. Why the Mesa Verde people decided to block the door is still a mystery.

A "Priests' Stone" at the north foot of the west vault was recorded by Earl Morris when he excavated the Great Kiva. He stated that, "The curious form of a semilunar stone, its polished surface, position relative to the western vault, and direct alignment with the western pillar justify the opinion that it was an important feature of the chamber, but nothing further can be said."* During the autumnal equinox, I held a mirror where the "Priests' Stone" was presumed to have been and directed a reflection of light to the top of the altar. If a Sun Priest had stood behind the altar during the rising sun of the equinox, his face would have been illuminated by the reflection of light off the polished stone. By turning the stone, other features inside the kiva could have been illuminated by its reflective surface.

* Morris, Earl H., "The House of the Great Kiva at the Aztec Ruin," Anthropological Papers of the American Museum of Natural History, New York, 1921; vol. 26, pt. 2.

At the time of the winter solstice, I watched the sun rise through the door of the peripheral room that is located in front of the southwest pillar. For an as yet unknown reason, the ancient Chacoans placed the pillar so that it would block the light from the rising sun of the winter solstice from entering the main chamber. Instead, the light strikes the pillar, and its reflection off the pillar creates a warm glow of light against the southeast section of the wall.

As the winter solstice sun sets, the light passes through the door of the west peripheral room and strikes the east wall of the Great Kiva. This cue might have been used for the start of ceremony within the chamber, probably to signal the time for general winter activities to the inhabitants of the prehistoric pueblo.

The moon is also revered by the Pueblo Indians and its movements and cycles have been used as a calendrical device. The Anasazi may have also used its cycles as a calendar. My studies of the full moon in the House of the Great Kiva show that it is visible from inside the chamber. At times, the full moon rises through the southeastern door of the peripheral room and its light strikes the southeast pillar. Then, as it continues to rise, its light passes through the door next to the pillar and can be seen inside the chamber. A priest standing behind the firepit could have seen the light from the moon on the pillar and then predicted that moonlight would strike the wall of the kiva. If so, it could have been used as a cue for ceremony and, then, as a part of the ceremony itself.

Venus, the morning star, has been associated with the Mesoamerican god Quetzalcoatl, and it is also the subject of many Pueblo Indian myths and legends. At times, Venus may be observed from the same peripheral room that the winter solstice sun rises through. However, at the time that I observed Venus it could be seen only from the peripheral room and not from inside the chamber.

The sun, moon, stars, planets and other astronomical phenomena are very important to the religious and calendric values and ideals of the Pueblo Indians. How other people in other times perceived the universe may be different from our own perceptions. The importance of these celestial spheres to the ancient Anasazi can be demonstrated by observations taken inside the cosmic chamber of the House of the Great Kiva.

(From Sunrise magazine, June/July 1989; copyright © 1989 Theosophical University Press)


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