Looking at petroglyphs always brings up questions about those who created them, the way in which they were created, and why they were created. Here are our questions while observing the sun's shadow move through the spiral petroglyph at Una Vida at Chaco Canyon, near the spring equinox.
The photos are of petroglyphs on the cliff face up behind Una Vida, near the Visitor Center.
- What caused the shadow?
By observation over these three days, we guessed it was the top edges of the rock face on which the petroglyph sat. Was it already that way naturally, or did they modify the rock to more perfectly align?
Look at the top right portion of the rock, just below the blue sky, and the shadow below, in the first photo. The petroglyphs are in the middle right of the smooth rock face.
- What was their process for creating the spiral, in relation to the movement of the sun?
Were the petroglyphs already created, and the movement of the sun's shadow on the spiral at equinox was a coincidence, and they perhaps modified or added to the spiral (and perhaps the rock above) as a result?
Did they observe the sun first, and create the spiral once they saw how and when the shadow moved across the rock?
- How did they create these pecked drawings in the rock, in days when there were no such things as erasers or the delete key?