Thursday, April 2, 2009

Archeo-astronomy, cupula rock

Archeoastronomy is the science of using what we know about astronomy, specifically naked-eye observations, to infer meaning in archeological artifacts. My knowledge of this subject comes mostly from Ray Williamson's book, Living the Sky, and from an inlaw who's contribution is cited within Williamson's book. Living the Sky also mentions constellations in great basin petroglyphs, and a possible example from the Temecula Valley is shown here:

Native americans left at least two records on local rocks: 1) grinding holes used in the preparation of food, and 2) smaller holes such as those you see in the rock above. These holes are about the size of a golf ball split in half, possibly ground with a rock of this size. When the sun is overhead shadows are cast, making the holes look like dark stars on pale rock.

A group of stars in the middle bears a strong resemblance to the constellation Cassiopeia, with one qualification: The hole at the apex of the 90-degree angle in Cassiopea is not like the others; it appears to be natural, suggesting either that the carver exploited a natural nook (quite understandable if you've ever tried to drill rock or scrape out a fossil) or that the excellent match to Cassiopea is a coincidence.
These cupulas can be found throughout the desert of Southern California. Below is an example from Anza-Borrego Desert State Park. Though I can imagine several constellations in the rock shown above, I can't claim to see any in the one below.

In this post, I tried to model the type of language and caveats offered in the primary science literature. Any claim (e.g., in this case, that the holes could be constellations) is offered with any known evidence that would undermine certainty in this conclusion (e.g., not all of the holes in Cassiopea were necessarily drilled by human hands). And so it was when I read an paper in Nature (in 2000?) that claimed the first observational evidence of the greenhouse effect. The authors did not declare themselves right and sceptics wrong. They merely stated something like "should our observations be corroborrated by further research...." They also cited concerns over the field of view and resolution of the instruments used in their analysis. This willingness to expose strengths and weaknesses in our observations and beliefs is a characteristic of good science, and is an attribute we can look for in determining whether we are reading science or propoganda.


Bill Wixted said...

I've read that the Polynesians used star maps to navigate the Pacific ocean so it seems reasonable to conclude that the native Americans did something similar.

jg said...

Hi Bill,
I'd love to see a polynesian star map. Maybe you could pick one up next time you're out that way.

I'm hoping to show the cupula rock picture to Ray Williamson. His book describes the use of stars as calendar markers. A star's first appearance in the morning sky was often used to identify a time of the year. For example, he cites the Navojo's using the constellation Corvis to mark the beginning of their winter hunting season.