Heiligenschein, or holy light, is a subtle, yet amazing phenomenon in which observers facing away from the sun see their shadows with a lighter glow around their head than the basic background tone.
Wikipedia describes it as an “optical phenomenon which creates a bright spot around the shadow of the viewer's head. It is created when the surface on which the shadow falls has special optical characteristics. Dewy grass is known to exhibit these characteristics, and creates a Heiligenschein. Nearly spherical dew droplets act as lenses to focus the light on the surface beneath them. Some of this light 'backscatters’ in the direction of the sunlight as it passes back through the dew droplet. This makes the antisolar point appear the brightest."
photographed by author, Aurora, CO,
"The opposition effect creates a similar halo effect, a bright spot of light around the viewer's head when the viewer is looking in the opposite direction of the sun, but is instead caused by shadows being hidden by the objects casting them.”
These phenomena are believed to be the cross-cultural cause of commonly portraying holy figures with a halo or spiritual glow around their heads so commonly found in the history of western art. If this was true for a number of religious beliefs world-wide why would we not assume that Native Americans would have also noticed this phenomenon and also portrayed it in their art. Rock art images that show figures with arcs or rays around their heads are usually identified as wearing headdresses, and I am sure that this is usually correct – but always? Would not an effect as striking as heiligenschein be just the sort of thing that we might expect to be recorded as a miraculous or spiritual event? If I were a Native American on my vision quest, and suddenly one morning I saw my shadow, cast by the rising sun and outlined by the bright glow of heiligenschein, might I not be justified in assuming that something powerfully spiritual had happened to me? And would I not want to record that marvelous event?
Heads with rayed headdresses, Yakima,
WA, photographed by the author, 1983.
As I said above we see reports of rock art figures with full headdresses, but we do not always know whether those cultures wore full headdresses. Some of our more psychically inclined colleagues see those same figures as displaying auras but this is a phenomenon that I have yet to see evidence for. I do think it that it is time that we try to explain the various features of rock art imagery based upon scientific truth when we can find it, and both heiligenshein and the opposition effect are scientific phenomena that I have both seen and photographed. I believe we need to keep it in mind as a possibility.
A beautiful book on atmospheric phenomena, optical and otherwise, is Robert Greenler, Rainbows, Halos, and Glories, 1980, Cambridge University Press, London, New York. Illustrated with many photos and with explanations of the optics behind them, it may have insights into some rock art imagery otherwise unexplained.