Has a Biochem Undergrad Solved a Cosmic Radiation Mystery? 156
scibri writes "A few weeks ago, reports of a mysterious spike in carbon-14 levels in Japanese tree rings corresponding to the year 775 intrigued astronomers. Such a spike could only have been caused by a massive supernova or solar flare, but there was no evidence of either of these at that time. Until Jonathon Allen, a biochem undergrad at UC Santa Cruz, Googled it. He found a reference in the Anglo-Saxon Chronicle to a 'red crucifix' appearing in the sky in 774, and speculates that it could have been a supernova hidden behind a cloud of dust, which could mask the remnants of the exploded star from astronomers today."
A few weeks ago in slashdot... (Score:5, Informative)
A.D. 774. This year the Northumbrians banished their king, Alred, from York at Easter-tide; and chose Ethelred, the son of Mull, for their lord, who reigned four winters. This year also appeared in the heavens a red crucifix, after sunset; the Mercians and the men of Kent fought at Otford; and wonderful serpents were seen in the land of the South-Saxons.
http://omacl.org/Anglo/part2.html [omacl.org]
Twas' a comment by JustOk. [slashdot.org]
Re:physics question (Score:5, Informative)
The radiation turns one proton in a nitrogen atom into a neutron, changing the atom from nitrogen to carbon, with two extra neutrons.
Re:physics question (Score:3, Informative)
If you'd bothered to wikipede: "Cosmic rays are energetic charged subatomic particles, originating in outer space.They may produce secondary particles that penetrate the Earth's atmosphere and surface. The term ray is historical as cosmic rays were thought to be electromagnetic radiation." http://en.wikipedia.org/wiki/Cosmic_rays
"Carbon-14 is produced in the upper layers of the troposphere and the stratosphere by thermal neutrons absorbed by nitrogen atoms. When cosmic rays enter the atmosphere, they undergo various transformations, including the production of neutrons."
http://en.wikipedia.org/wiki/Carbon-14
Re:physics question (Score:3, Informative)
It's only a few nuclei that fall completely apart when they encounter a neutron. In fact, the first time physicists observed that happening, it was so unexpected that they didn't realize at first that it was what they were seeing.
Most absorb the neutron, often having a secondary reaction that changes them to a different element.
Tritium is not sorted out of seawater. With a half-life of 12 years it isn't found in nature. You may be thinking of deuterium.
Re:A few weeks ago in slashdot... (Score:5, Informative)
You're simply not going to get a definitive record of a celestial event in 8th century Europe. Records are very scanty, often non-existent. This is so marked that it's led to an entertaining conspiracy theory [wikipedia.org] or two [wikipedia.org] claiming that the early Middle Ages didn't actually exist and were faked at some later date. Back in the real world, there's so little evidence for most things about Anglo-Saxon England that the claim that the people of York chose Ethelred, son of Mull to be their king is almost as suspect as the claim about the wonderful serpents.
So the best you can usually hope for in the English 8th century is a monk somewhere recording events in the Anglo-Saxon Chronicle (or a Anglo-Saxon Chronicle -- there were a few of them made at different times and in different places). The Chronicle doesn't really go for detail. They sum up a year in a few declarative sentences, with no description, so you're never going to get a description of a celestial event, you're going to get a simplfied interpretation of it. This interpretation will be in terms that the monk or the eyewitnesses he got his information from understood. They didn't know anything about supernovas, but he knew about miraculous crosses in the sky, like that which appeared to the future Roman Emperor Constantine during his fighting against his rival Maxentius. So whatever it was that someone saw, it got interpreted as a crucifix.
The point isn't that something definitely appeared in the sky in 774. There's a chance that someone made up the red crucifx, or hallucinated it, or the chronicler lied or garbled a story he heard fifth-hand. But if it did happen, there's no reason to think that there will be better written evidence than a vague line in one copy of the Anglo-Saxon Chronicle.
Re:Religious misinterpret phenomenon (Score:3, Informative)