Is this a Supernova? Photo by John Barentine, Apache Point Observatory
I picked up the story Ancient rock art chronicles exploding star yesterday, but I don’t know what to make of it. It’s another example of how a news story misses what is so interesting.
Briefly, a talk at the 208th meeting of the American Astronomical Society suggests that a Hohokam petroglyph might depict the great supernova of AD 1006. The remnants of this explosion can only be seen through a telescope today, but at the time it may have been the brightest star in the sky by a long way. Bright enough to read by. It’s not surprising that there are historical records of it around the world, but no record of it has been found in North America till now.
The talk relates an image to another petroglyph depicting Scorpius. This is what I find both really interesting and a bit odd, because I don’t know how they worked out the petroglyph was a constellation and that it was Scorpius. The picture looks like a scorpion, but does that automatically make it a constellation? If it does then must this scorpion be in the same part of the sky as the Graeco-Roman constellation Scorpius?
The only constellation records I could get my hands on from the region are the Navajo constellations. In these one part of Scorpius, along with Sagittarius, is part of a man with a staff. The other part is an entirely different constellation, the Rabbit Tracks. I’ve asked on HASTRO-L and Steve McCluskey has said that there’s no reason to assume continuity between Navajo and Hohokam cultures, they’re too far apart in time, geography and economic patterns, so you wouldn’t expect the astronomies to be similar.
Unlike the Navajo there is no living Hohokam people so interpretation has to be purely archaeological. Unfortunately (?) there are thousands upon thousands upon thousands of petroglyphs in the American southwest. Simply picking glyphs to fit a theory would be easy, and with such a bright star it would be really really strange if no-one drew it. So the news report tells me nothing I can get excited about. It tells me that ancient Americans saw a supernova which shone around magnitude –7.5 but I could have guessed that. The really exciting and archaeologically useful bit, that it might be possible to identify constellations in petroglyphs, is completely glossed over.
I’ll have to wait for the publication before I can make sense of it.