The Sun Dagger of Chaco Canyon
Near the top of a butte in New Mexico, a blade of sunlight slices through the centre of a carved spiral at midday on the summer solstice.
What was reported
In 1977, the artist Anna Sofaer was recording rock art on Fajada Butte, in Chaco Canyon, the great centre of the Ancestral Puebloan world. Behind three tall stone slabs leaning against the cliff, she saw a spiral carved in the rock, and a dagger of sunlight passing across it.
Later study found that at the summer solstice, a single sliver of light cuts through the centre of the spiral; at the winter solstice, two daggers frame it exactly; at the equinoxes, a smaller dagger crosses it. The design may also track the Moon's long cycle.
Explanations offered
Whether the slabs were placed by people or fell naturally, and the carvings made to fit them, is debated, but the alignments are real. The slabs shifted in the 1980s, possibly because of erosion from visitors, and the site is now closed to protect it.
- When
- Carved about 1,000 years ago; found in 1977
- Where
- Fajada Butte, Chaco Canyon, New Mexico, USA
- Witnesses
- An artist who climbed the butte
- Status
- Partly explained
Famous cases are real, widely reported events. Each file sets out what witnesses said and the explanations that have been offered, without taking a side.
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