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First Evidence of Supernovae Found In Ice Cores
KentuckyFC writes "Supernovae in our part of the Milky Way ought to have a significant impact on the atmosphere. In particular, the intense gamma-ray burst would ionize oxygen and nitrogen in the mid to upper atmosphere, increasing the levels of nitrogen oxide there by an order of magnitude or so. Now a team of Japanese researchers has found the first evidence of a supernova's impact on the atmosphere in an ice core taken from Dome Fuji in Antarctica. The team examined ice that was laid down in the 11th century and found three nitrogen oxide spikes, two of which correspond to well known supernovae: one event in 1006 AD and another in 1054 AD, which was the birth of the Crab Nebula (abstract). Both were widely reported by Chinese and Arabic astronomers at the time. The third spike is unexplained, but the team suggests it may have been caused by a supernova visible only from the southern hemisphere or one that was obscured by interstellar dust."
1054 AD, which was the birth of the Crab Nebula
The Crab Nebula is 6,500 light years away from earth (http://en.wikipedia.org/wiki/Crab_Nebula).
This means the birth of the Crab Nebula was in the year 5446 BC. Mankind witnessed it 6,500 years later.
News stories on such phenomena invariably leave out this little fact, i.e., that which is witnessed by man in the sky usually happened thousands of years earlier than when he actually saw it. This makes it confusing for the average reader.
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Only a matter of time until they find an actual frozen supernova in the ice.
Hmm... "birth of the Crab Nebula" or "death of the Great Crab Civilization"?
You decide.
If these really are the supernovae, doesn't this mean that "model B" is right and "model A" is wrong?
The two models look like extrema that bound the dates.
More interestingly, the sharpness of the spikes indicate that the sealing of atmospheric gases in the ice happens very suddenly. If it did not we would expect to see much broader and probably asymmetrical peaks.
This is consistent with, but does not absolutely prove, a rather prompt mechanism for such sealing, rather than the long lagtime process that is sometimes invoked to explain why temperatures always rise tens or hundreds of years before CO2 levels do in ice core data. It would be very peculiar, albeit not impossible, to have a process that sealed the ice tens or hundreds of years after it was laid down as snow, but did so on a timescale of a year or so.
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You're citing an 1980 article from "Aramco World Magazine" to introduce a bunk story on par with lost-city-of-atlantis myths. It's not even a peer reviewed journal. It's a magazine. You're giving these Piri Reis maps much more credit than they deserve. You say they
closely resemble an ice-free Antarctica
but from what I just read the maps didn't even have a waterway between Antarctica and South America. An ice free antarctica should have a *huge* friggin' waterway there.
If these maps are correct, and there was no ice in the 1500's... how were these ice cores found?
They aren't correct. See above.
We have ice cores that we know go back more than 400,000 years. Give the guys who date these cores some credit. To me this iceless-antarctica idea just looks like a retired old historian/cartographer pushing a crackpot hypothesis. Yes, Antarctica wasn't always covered in ice, but that was millions of years ago.