The 993–994 carbon-14 spike was a rapid 0.91% increase in carbon-14 isotope content from tree rings dated 993-994 CE. This event was also confirmed with an associated increase of beryllium-10 in Antarctic ice core samples, supporting the hypothesis that this event was of solar origin. There were several astronomical observations during this time that correspond with the C and Be spikes, but these texts are few and far between.
In 2021, a scientific paper used the 993–994 carbon-14 spike as a benchmark in dendrochronology (tree-ring studies) to precisely determine that Vikings were present in L'Anse aux Meadows in Newfoundland exactly 1000 years prior, in 1021 AD.
Historical observations
The solar storm hypothesis is heavily supported by several observations of aurora events from late 992 in Korea, Germany and Ireland, usually describing a red sky, presumably because of major auroras. The historical observations do not completely prove the cause of the 993-994 C spike but show evidence of a strong solar event taking place late 992, as they were recorded within a relatively short time frame.
In the Korean Peninsula, between December 992 and January 993, a text described "heaven's gate" opening one night.
In the Saxony region of present-day Germany in late 992, several aurora observations were made. One set of observations, recorded October 21, 992, noted that the sky reddened three times. Another set of observations, made December 26, 992, mentioned a light as bright as the sun shining for an hour, then reddening the sky, before vanishing completely.
In the Ulster region of present-day Northern Ireland on December 26, 992, texts described the sky as "blood-red" and having a "fiery hue".
Similar events
The 993–994 carbon-14 spike was one of only a few well-documented C events. There had been a considerably larger one, the 774–775 carbon-14 spike, which was around 1.7 times as strong than the 993-994 event. Both events also had subsequent Be spikes, which further proves that they are from strong solar activity.
See also
References
- Miyake, Fusa; Hakozaki, Masataka; Kimura, Katsuhiko; Tokanai, Fuyuki; Nakamura, Toshio; Takeyama, Mirei; Moriya, Toru (2022-07-04). "Regional Differences in Carbon-14 Data of the 993 CE Cosmic Ray Event". Frontiers in Astronomy and Space Sciences. 9: 886140. doi:10.3389/fspas.2022.886140. ISSN 2296-987X.
- ^ Miyake, Fusa; Masuda, Kimiaki; Nakamura, Toshio (2013-06-26). "Another rapid event in the carbon-14 content of tree rings". Nature Communications. 4 (1): 1748. Bibcode:2013NatCo...4.1748M. doi:10.1038/ncomms2783. ISSN 2041-1723. PMID 23612289.
- Dee, Michael W.; Pope, Benjamin J. S. (August 2016). "Anchoring historical sequences using a new source of astro-chronological tie-points". Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences. 472 (2192): 20160263. doi:10.1098/rspa.2016.0263. ISSN 1364-5021. PMC 5014109. PMID 27616924.
- ^ Hayakawa, Hisashi; Tamazawa, Harufumi; Uchiyama, Yurina; Ebihara, Yusuke; Miyahara, Hiroko; Kosaka, Shunsuke; Iwahashi, Kiyomi; Isobe, Hiroaki (January 2017). "Historical Auroras in the 990s: Evidence of Great Magnetic Storms". Solar Physics. 292 (1): 12. arXiv:1612.01106. Bibcode:2017SoPh..292...12H. doi:10.1007/s11207-016-1039-2. ISSN 0038-0938. S2CID 255073793.
- ^ Mekhaldi, Florian; Muscheler, Raimund; Adolphi, Florian; Aldahan, Ala; Beer, Jürg; McConnell, Joseph R.; Possnert, Göran; Sigl, Michael; Svensson, Anders; Synal, Hans-Arno; Welten, Kees C.; Woodruff, Thomas E. (2015-10-26). "Multiradionuclide evidence for the solar origin of the cosmic-ray events of ᴀᴅ 774/5 and 993/4". Nature Communications. 6: 8611. Bibcode:2015NatCo...6.8611M. doi:10.1038/ncomms9611. ISSN 2041-1723. PMC 4639793. PMID 26497389.
- ^ Stephenson, F. Richard (2015-03-15). "Astronomical evidence relating to the observed 14C increases in A.D. 774–5 and 993–4 as determined from tree rings". Advances in Space Research. 55 (6): 1537–1545. doi:10.1016/j.asr.2014.12.014. ISSN 0273-1177.
- Kuitems, Margot; Wallace, Birgitta L.; Lindsay, Charles; Scifo, Andrea; Doeve, Petra; Jenkins, Kevin; Lindauer, Susanne; Erdil, Pınar; Ledger, Paul M.; Forbes, Véronique; Vermeeren, Caroline; Friedrich, Ronny; Dee, Michael W. (2022-01-20). "Evidence for European presence in the Americas in ad 1021". Nature. 601 (7893): 388–391. doi:10.1038/s41586-021-03972-8. ISSN 0028-0836. PMC 8770119. PMID 34671168.
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