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What Struck Earth in 775?
ananyo writes "Just over 1,200 years ago, the planet was hit by an extremely intense burst of high-energy radiation of unknown cause, scientists studying tree-ring data have found. The radiation burst, which seems to have hit between 774 and 775, was detected by looking at the amounts of the radioactive isotope carbon-14 in tree rings that formed during the 775 growing season in the Northern Hemisphere. The increase in 14C levels is so clear that the scientists conclude that the atmospheric level of 14C must have jumped by 1.2% over the course of no longer than a year, about 20 times more than the normal rate of variation (abstract). Yet, as the only known events that can produce a 14C spike are supernova explosions or giant solar flares, and neither event was observed at the time, astronomers have a cosmic mystery on their hands."
Would this mean carbon dating is inaccurate for items older than 1300 years?
Things that were alive in 775 appear to have more C14 than usual, so even after centuries of decay, they'd still have more C14 than usual, which would make them measure younger. This is my understanding from reading the "Amateur Scientist" column in "Scientific American" about doing radiocarbon dating at home. SciAm used to be a pretty cool magazine, well, 50 years ago. When I was a high school kid I spent about two weeks one summer reading on microfilm pretty much every Amateur Scientist column from the 30s (when it was all telescopes) until the 70s when it started sucking. You can buy a collection of those columns on a cdrom now, of course.
Time to redate the Shroud of Turin?
I'm not up on my mythology, but I think it's made of woven plant or animal fibers, and this would have no effect unless the plants or animals that made it were alive in 775. If it was grown in 775, then it would be misdated to be somewhat younger. I might misremember but isn't the mythology something along the lines that it was grown just a short time before year 0 ? This error is going in the opposite direction then. Or theres some alternate mythology as regards templars and freemasons and such, which is too recent to be fixed by the error.
Or the TLDR summary version of the above is ... "no, and no".
"Science flies us to the moon. Religion flies us into buildings." - Victor Stenger
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
rewriting history since 2109
No, scientists have known for a long time that the 14C creation rate isn't quite constant, and have taken this into account in order to do accurate radiocarbon dating. In fact, it was by looking at this carbon-dating calibration curve that they first noticed something unusual in 775.
http://www.nature.com/nature/journal/vaop/ncurrent/full/nature11123.html
If the supernova was behind or near the Sun, earthlings around 775 wouldn't have been able to detect it.
Nearby supernovae appear as one of the brightest objects in the sky for a few days to a week. The remnants remain visible for months, and then have a habit of leaving a nebula behind.
The Earth travels slightly more than one degree of its orbit per day; The Sun, as seen from the Earth, subtends half a degree of arc. In the absolute worst case, the sun couldn't completely "hide" a supernova for more than a single day; and half a week later, the supernova remnant would dominate the dusk (or dawn) as the brightest thing in the sky except possibly the moon.