A mysterious pattern of stones sits at the summit of Medicine Mountain, nearly 10,000 feet above the Big Horn Mountains of northern Wyoming exists a massive medicine wheel. Covered by heavy snows for most of the year, the stone configuration reveals itself and its purpose only in the summer months.
The stones are arranged in the shape of a wheel, 80 feet across and with 28 spokes emanating from a central cairn. The cairn, a ring-shaped pile of rocks, is large enough to sit in and is surrounded by six others that lie along the wheel’s circumference. Oddly enough, this configuration is not unique to Wyoming. Rather, hundreds of similar stone wheels exist throughout North America. Of the various medicine wheels throughout the continent, Bighorn is one of the most well studied and preserved.
The Big Horn Mountains was significant to the Crow, the Sioux, the Arapaho, the Shoshone, and the Cheyenne Indians—but none of these tribes were known for building stone monuments. Bits of wood found in one of the six smaller groups situated unevenly about the rim indicates that the Medicine Wheel has been there since at least 1760 and was likely constructed around 1700. The monument has been known to non-natives for over a hundred years, but speculation about its true purposes has only inspired mysteries and tales.
John A. Eddy, a solar physicist and astronomer on the staff of the High Altitude Observatory, National Center for Atmospheric Research, in Boulder, Colorado, became interested in the site, especially after he discovered a large, crude pile of stones oriented to the summer solstice sunrise at over 11,000 feet on the Continental Divide. Interested by this discovery, he wanted to investigate just how much the pre-contact native people might have known of astronomy, and it occurred to him that the wheel might have been an observatory. Research over two summers on the site convinced him that the Big Horn monument may have been a primitive astronomical observatory that served its creators at least as well as Stonehenge served its primitive astronomers.
The high altitude (9,640 feet) and the clear horizons of the monument make visible the marking of sunrise and sunset at the summer solstice. The accurate knowledge of the first day of summer would have been very important for a nomadic people whose lives depended on awareness of seasonal changes.
Today, the Bighorn Medicine Wheel is still an accurate predictor for the summer solstice and is used by various Native American groups. Additionally, the site is a registered National Historic Landmark and is monitored by an archaeologist throughout the summer. Other important medicine wheels include one at Moose Mountain in Saskatchewan and one in Majorville, Alberta that is believed to be 5000 years old, making it coeval with the pyramids in Egypt.