Chaco
Possible petrographs: 1054 Supernova (now Crab Nebula) above, Halley's comet below.
photo by Ron Lussier

1054 Supernova Petrograph

Dan Greening

The Anasazi residents of Chaco Canyon were attentive to the movements of the heavens, that much is clear. The famous Sun Dagger on Fajada Butte in the center of Chaco Canyon is a solar calendar that heralds the winter solstice when a band of sunlight passing through between two slabs intersects the center of a spiral. A square of light floods a notch in the wall of Casa Rinconada's Great Kiva on the summer solstice, and locations marked within the Great Kiva are thought by some to create a simple stellar observatory.

There are many similar phenomena throughout Chaco Canyon and San Juan basin to the northwest. Sometimes a correlation suggests a dubious conclusion, another might seem obvious. Regardless of the validity of any particular claim, there is little doubt that the Chacoans cared about what happened above them, because there are so many correlations.

If you look through a telescope tonight, in the constellation Taurus, you will see a formation we call the "Crab Nebula." This cloudy, glowing mass comprises about 90% of the remains of a supernova that first appeared here around July 4, 1054.

A supernova is the explosion of a large star. Our sun is too small to create a supernova. The star that created the Crab Nebula was much bigger. When a supernova occurs, the majority of the matter in the star is blown out at nearly the speed of light. If you are close, you don't get to watch it very long before you are blown to bits. If you are far away, it will look like a very bright star, once the light from the explosion has taken its time to reach you.

The star that caused the 1054 supernova is about 4000 light years away, and much of the supernova's energy had diminished through space before it reached the earth. Nevertheless, on July 4, 1054, 4000 years after the Crab Nebula supernova actually occurred, a star six times brighter than Venus appeared in the sky. It was visible on Earth at high noon, and stayed visible for 23 days. The supernova was so strong that had it occurred within 50 light years of Earth, all living things on the planet might have been destroyed.

The Chinese and Japanese record the appearance of a very bright "guest star" around this time. And if you were a Chacoan living at the same time, you would notice it, probably even record it.

In fact, on the underside of a shelf below West Mesa in Chaco Canyon, just outside the great house called Peñasco Blanco, is a panel containing three symbols: a large star, a crescent moon, and a handprint.

Halley's comet made its appearance just a few years after the 1054 supernova. If you were a Chacoan living around this time, you would definitely notice Halley's comet: its appearance threw many civilized peoples into fear. And since observing the heavens was an important aspect of Chacoan culture, you would probably record it.

Perhaps you would record Halley's comet where you depicted another one-time astronomical event: below West Mesa, near Peñasco Blanco. Below the star, hand, and moon, in a distinct panel, are three concentric circles, approximately a foot in diameter, with huge red flames trailing to the right. The flames are now so faint that black and white pictures often fail to record it.

Drawing conclusions from these correlations is speculation: we can't ask the Chacoans why they drew the things they did. But the circumstantial evidence is very strong.

Every 18 1/2 years, the moon and earth return to approximately the same positions they had on July 4, 1054. If you happen to be in Peñasco Blanco around this time, situate yourself with a telescope under that shelf of West Mesa and look up in the sky. Wait until the moon is in a position pointed to by the fingers of the hand. And then use the diagram under the shelf to position your telescope at the large star in the petrograph. Look in your telescope, and you will see the Crab Nebula.

And perhaps you will imagine how the Chacoans felt the day a visiting star appeared in their sky.


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