Earth & Sky

Special thanks to:

Dr. Kolleen Bean
US Forest Service Archaeologist
Medicine Wheel Ranger District
Bighorn National Forest

Dr. Anthony Aveni
Russell B. Colgate Professor of Astronomy and Anthropology
Colgate University
Hamilton, NY

Suggested Readings

Living the Sky: The Cosmos of the American Indian Ray A. Williamson, Wadsworth University of Oklahoma Press, 1987; ISBN 0-8061-2034-7

Stars of the First People: Native American Star Myths and Constellations Dorcas S. Miller, Pruett Publishing Co., 1997; ISBN: 0-8710-8858-4

Author’s Notes

The Bighorn Medicine Wheel was the first of North America’s medicine wheels to be carefully measured by astronomer John Eddy in June 1972. Since then, 40 to 50 other medicine wheels that show astronomical alignments have turned up all over the plains, spreading from the U.S. into Canada.

At least a few dozen date to the time of first contact with Europeans. Others date back to the early part of the Christian era. This suggests to us that building these sacred places is a long-established tradition, widespread among the tribal cultures of North America. One could almost say it was as common as flag making. All nations have flags. This was a very important part of the religion and social structure in these societies.

Eddy began his work by using Bighorn’s rock piles, or cairns as aiming sights for astronomical objects rising and setting above the horizon. He saw that sunrise and sunset on the first day of summer, June 21, lined up with Bighorn’s center rock cairn and two outside rock cairns. After seeing this, he began searching for any other astronomical alignments between the four other outside cairns and the center cairn.

Snow-cover between late August and late May makes the wheel unusable except during the summer months. So he set out to check for alignments between cairns and bright stars that might be visible rising before the sun during summer. Through careful surveying and analysis, Eddy found that several hundred years ago three cairn parings lined up with three of the nine brightest stars in the Northern Hemisphere sky as they rose before the summer sun.

Over time, the Earth slowly wobbles on its axis. This effect, called precession, makes stars appear in slightly different places in our sky over time. Eddy adjusted for hundreds of years of this effect until, to his amazement, he found that the bright star Aldebaran, in the constellation of Taurus the Bull, rose just before the Sun within one or two days of summer solstice. Indian skywatchers could glimpse its appearance in the brightening sky, lined up over a pair of outside cairns, on the morning of solstice arrival. On top of that, Orion’s bright star Rigel rose just before the sun over still another cairn pair 28 days later, or one month after the summer solstice. This was followed another 28 days later by the rising of Sirius along the line of sight with still another pair if cairns.

Why all the redundancy? The sun’s rising point on mornings near solstice sunrise moves very slowly along the horizon, making it harder to pinpoint the actual June 21 sunrise position over the center cairn. Here the Aldebaran sighting was most immediately useful. Glimpsing it just before a sunrise narrowed solstice estimation accuracy to within one or two days. So to hit summer solstice arrival on the head, native skywatchers needed three simultaneous occurrences: sunrise and sunset over the central cairn and two distinct outside cairns, and for Aldebaran to rise over its cairn pair just as the sun rose. By noting these three conditions, they could determine the summer solstice arrival with uncanny accuracy.

To further verify these findings, 28 days later native skywatchers would note Rigel rising just before sun-up over its cairn pair. To add still more confidence, they’d look for a final star, Canis Major’s Sirius, to rise over another distinct cairn pair in August, some 28 days after noting Rigel’s rise in July. Backtracking the days, native observers could then reinforce their original determination of summer solstice in June. As it happens, 28 spokes radiate from the central cairn to a stone rim. They would have lent themselves as a natural tool for counting days between bright star risings.

A few years after John Eddy’s work, another astronomer, Jack Robinson, found a cairn pair that marked another bright star’s, Fomalhaut’s, rising point with the sun, but this time 28 days before solstice.

Bear in mind that all these alignments were ideal some time ago, due to the effect of precession. This gives astronomers powerful tool for dating when the wheel was built and most accurate. After accounting for precession, scientists figure it was constructed in 1200, and remained very accurate until 1700, when precession started throwing off star rising times.

Alignments for solstice sunrise and sunset, however, remain useful to this day.

We’ll probably never know for sure the true nature of native medicine wheels like Bighorn. They probably served many functions for different people in different eras. For example, consider older buildings around us today. Joe’s Garage wasn’t always Joe’s Garage. Before that, it might’ve been a bowling alley, and before that, a movie theatre. And a church isn’t just a place of worship. Why else would they have bingo? Form and function of many human structures changes as humans themselves change.

Eddy’s landmark 1972 Bighorn study was a big splash because it came in the aftermath of the Stonehenge controversy. Like Stonehenge, Bighorn was a round structure made out of stones, though it’s not as big and as old as Stonehenge. Eddy was seizing on a paradigm that ancient round structures made of stone had something to do with astronomy. It was a hot research in those days. Now, 20 years later, arguments advocating precision astronomy as the primary reason for many of these ancient sites are beginning to die down. Reanalysis of all the data suggests that scientists may have gone a little too far in the direction of precise astronomy.

While medicine wheels like the Bighorn do have astronomically-oriented features, sighting the sky probably played a supporting role to their primary function. They undoubtedly served as ceremonial structures where one could go to have a dream-induced vision or commune with the gods. Why else would they be on high places? Some medicine wheels were also places of assembly. Spokes pointing to the center served as a focus, where people converged for purposes of worship, to disperse into tribes, or trade goods. They were meeting places, and in every meeting place, you’d expect to have a calendar, a means to judge phases of the moon, the appearance of the sun, or rising of bright stars. It told people when the time was right to come, or go. The problem is that we can’t fit all medicine wheels into set categories. All we can say is that, yes, there are hints of orientation, yes some do have hints of burial, and yes there are hints of ceremonial structure. We can’t say more unless we consider each wheel, case by case.