A Case Study
A limestone
rock circle with varying diameters of around 75 to 87 feet and a perimeter
of 75 feet, the Bighorn Medicine wheel is formed by 28 spokes meeting
at a central cairn 12 feet in diameter and 2 feet high, 5 smaller cairns
lie around the rim of the circle where spokes radiating from the center
meet the rim. Another spoke extends out of the circle for 13 feet and
also ends in a cairn. The 28 spokes in the wheel give the approximate
number of days in a lunar month. Dr Eddy was a solar astronomer at the
High Altitude Observatory of the National Center for Atmospheric Research
in Boulder, Colorado when he discovered that the cairn at the end of the
spoke extending out of the stone circle has a summer solstice sunrise
alignment. The view from that cairn crosses the central cairn to see the
summer solstice sunrise on a low ridge to the northeast. This also coincides
with the circle's axis of symmetry. The significance of the summer solstice
at the site is further shown when we take into account the fact that at
the height of the wheel above sea level, the area is free of snow only
for 2 months in summer during which the summer solstice takes place.
Further
research showed Dr Eddy that 4 of the other cairns also had astronomical
alignments; one with the summer solstice sunset and the other 3 with the
rising points of the stars Aldebaran in Taurus, Rigel in Orion and Sirius
in Canis Major. Interestingly enough, these 3 stars also play symbolic
roles in the Cheyenne Massaum ceremony and are also important stars in
the sacred Lakota circle constellation The Animal. During the period of
time from 1600 AD and 1800 AD, these stars would have acted as solstice
markers by rising before the sun - Aldebaran during the 2 days before
the solstice, Rigel for 28 days after the solstice, and Sirius for the
next 28 days. Jack H Robinson, at the University of South Florida, showed
for the last remaining cairn that the backsight for it coincided with
the rising star of Formalhaut, which rose before the sun 35 days before
the summer solstice during the time frame of 1050 AD to 1450 AD. Thus,
while the stellar datings and tree ring dating differ to a certain extent,
we can limit the range of time that the wheel was constructed in to the
time frame of 1000AD to1800AD, give or take a few more centuries.
The theory of intentional astronomical alignment was further strengthened when Dr Eddy, along with archaeologist Thomas F. Kehoe, showed that a medicine wheel 425 miles away from Bighorn on Moose Mountain, in southeastern Saskatchewan, had similar astronomical patterns incorporated into the layout. The central cairn at Moose Mountain is 30 feet in diameter and 5 feet tall. 5 spokes extend out from this cairn beyond the perimeter of the circle. The longest spoke, aligned with the summer solstice sunrise, runs 123 feet out. Dr Eddy's stellar dating of the site showed it to be 2000 years old, while Kehoe's radiocarbon dating placed it around 440BC, although the date could be some centuries after or earlier.
Some people have argued against this theory of alignment by saying that the Native Americans could easily have predicted the position of rising stars and the sun by observing the landscape. Because of this, they assert that such astronomical functions in the wheels were not needed. However, the layout of the Bighorn Medicine Wheel would have allowed one to pinpoint the date of summer solstice down to the exact day with the help of posts and horizon features. The astronomical correlations may also be attributed to symbolic function.
Design similarities between the Bighorn and Moose Mountain wheels and other wheels have caused people to speculate that they were made by the ancestors of the Plains tribes or some other aboriginal culture that had widespread influence or movement across the plains. However, a study of all the 135 known medicine wheels by Canadian astronomer David Vogt carried out around 1990 concluded that while the wheels were intentionally orientated to serve symbolic religious purposes, the lack of an overall pattern to them prevents us from drawing clear cut conclusions on the identity of the cultures that built them.
Diagrams of other medicine wheels can be seen here. Teaching resources can be found here.