January 19 - January 25, 1995

Ancient Evenings

IN 2946 B.C. a star in the constellation Taurus went supernova.

When the light from that explosion finally reached Earth 4,000 years later, in 1054 A.D., some Chinese astronomers wrote down their observations. What they saw was an unparalleled stellar phenomenon. For 23 days light from this supernova was visible in the daytime sky. It was twice as bright as the planet Venus. For 653 days afterward it could be seen at night as though it were a new star. The Chinese referred to it as a "guest star." Today it's known as the Crab Nebulae, a gaseous cloud.

Remarkably, the only other reference to this extraordinary event found in the world came from a note by Baghdad doctor, who concluded the star caused an epidemic.

Unless you count the scores of depictions of a bright star next to a crescent moon found in American Indian rock art throughout the southwest, says Edwin C. Krupp, director of the Los Angeles' Griffith Observatory and a premier archeo-astronomy researcher.

Krupp spends a great deal of his free time investigating rock art that might possibly have astronomical connections.

In 1955 William C. Miller, an astronomer at Hale Observatories near Pasadena, California, was taking some pictures of rock art when he noticed a crescent shape next to a star, Krupp says. Assuming the crescent was a moon, (otherwise you're stuck with interpreting it as a banana, Krupp says) and the star referred to a celestial star, Miller concluded the image must be the supernova noted by the Chinese. During the first week of July 1054, the moon was in its crescent phase and the supernova appeared close to it in the night sky.

This analysis found some additional backing from archaeological evidence of the presence of a village nearby during the era when the supernova became visible.

Twenty years after this initial discovery, the supernova connection began catching on and eventually many crescent moon and star associations were discovered throughout the southwest, Krupp says.

He's quick to point out, however, that we'll never be sure what the artists were referring to.

"We need to be discreet and humble," Krupp says, "about how to interpret what we see."

Krupp says there is no system of rules established to reach any definitive conclusions about what the art represents.

"This is really pretty fun stuff, but it's not necessarily true," says Krupp. "The Chinese wrote everything down. An image without text is much more problematic to determine what it means."

Supernovae occur when stars much larger than the Earth's sun begin to run out of fuel. When their cosmic needles start pointing at empty, their fusion reactions decline. When the star runs out of fuel, gravity begins pulling the outer atmosphere of the star toward its core. Recent breakthroughs in astronomical models indicate that after the gaseous atmosphere begins collapsing, the gasses become heated and rise in convection cells. This rising gas creates extreme pressure inside the star that quite rapidly leads to a tremendous explosion--sort of like burned-out postal employees on a rampage.

The ensuing explosion and radiating gaseous debris create a luminosity 10 billion times brighter than the sun, says William K. Hartmann in The Cosmic Voyage: Through Space and Time.

While the supernova of 1054 long ago faded away, a great deal of rock art is still relevant to the modern skies--and still functioning!

Solar calendars dot the archeological landscape and make impressive sights when they come into alignment. Most of these calendars depend on a dagger of light filtering through boulders or a shadow being cast from an outcropping onto a smooth surface. On this surface concentric circles, figures or other representations are chiseled or drawn on the rock. At given times during the year, the sunlight touches particular points.

For instance, in the Cave of Light in Petrified Forest National Park, a beam of light pinpoints a cross drawn on the wall 45 days before the winter solstice. This is the time when the Hopi Indians conduct their fertility initiation ceremonies. The images of sex and fertility on the wall support the conclusion that this beam of light pinpointing the image on the rock is connected with the ceremony.

Constellations rarely find representation in rock art, says Krupp. One notable exception is the Navajo's "rabbit track."

Rabbit tracks in the sand look something like a "Y." The tail end of the constellation Scorpius also looks like a "Y" and Navajo Indians have indicated the tail of Scorpius and the rabbit track are one and the same. The appearance of the rabbit track in the dawn sky indicated the end of winter--a time of significant interest to any culture.

Krupp says his significant interest in astronomy and the impact the night sky has on the minds of people viewing it began when he was a kid.

"I've been curious about the way the mind interacts with the sky since I first read myths and stories and all this is a continuation," says Krupp.

Krupp sees this rock art as having a sort of window into the minds of ancient humans.

"What we're seeing," Krupp says, "is the fundamental visual vocabulary of human beings. It's a nonverbal expression of concerns, ideas and observations. It's a port of entry into the minds of the past, however limited, and allows, if not complete understanding, at least an inkling of what they were thinking."

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