Has a Biochem Undergrad Solved a Cosmic Radiation Mystery?
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.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
Twas' a comment by JustOk.
The radiation turns one proton in a nitrogen atom into a neutron, changing the atom from nitrogen to carbon, with two extra neutrons.