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| {{Short description|Observed increase concentration of carbon-14 in tree rings dated 774 or 775}} | |||
| The '''774–775 Carbon-14 Spike''' was an increase of 1.2% in the ] content of ] during the years 774 or 775 ], which was about 20 times as high as the background rate of variation. It was found during a study of ] trees, with the year of occurrence determined through ]. | |||
| The '''774–775 carbon-14 spike''' is an observed increase of around 1.2% in the concentration of the radioactive ] isotope in ] dated to 774 or 775 ], which is about 20 times higher than the normal year-to-year variation of radiocarbon in the atmosphere. It was discovered during a study of ] tree-rings, with the year of occurrence determined through ].<ref name="nature"/> A surge in ] ({{sup|10}}Be), detected in Antarctic ice cores, has also been associated with the 774–775 event.<ref name="usoskin"/> The 774–775 CE carbon-14 spike is one of several ]s and it produced the largest and most rapid rise in carbon-14 ever recorded.<ref name=intcal>{{cite journal |last=Reimer |first=Paula |display-authors=etal |title=The IntCal20 Northern Hemisphere Radiocarbon Age Calibration Curve (0–55 cal kBP) |journal=Radiocarbon |volume=62 |issue=4 |date=August 2020 |pages=725–757 |bibcode=2020Radcb..62..725R |s2cid=216215614 |hdl=1893/30981 |hdl-access=free |doi=10.1017/RDC.2020.41 |url=https://www.cambridge.org/core/journals/radiocarbon/article/intcal20-northern-hemisphere-radiocarbon-age-calibration-curve-055-cal-kbp/83257B63DC3AF9CFA6243F59D7503EFF#}}</ref><ref>{{cite web |title=Researcher points to Sun as likely source of eighth-century 'Charlemagne event'|author=University of Kansas |date=November 30, 2012 |url=https://phys.org/news/2012-11-sun-source-eighth-century-charlemagne-event.html}}</ref> | |||
| <ref name="nature"/> A surge in a specific isotope of ] (]), detected in Antarctic ice cores, has been associated with the 774-775 event.<ref name="usoskin"/> | |||
| The event appears global with the same signal found |
The event appears to have been global, with the same carbon-14 signal found in tree rings from ], ], the ], ], and ].<ref name="usoskin"/><ref name="jull"/><ref name="guettler"/> | ||
| <div style="float:right;">{{anchor|Fig_1}} | |||
| ] spike around 774 |
] spike around 774. Colored dots are measurements in Japanese (M12) and German (oak) trees; black lines are the modeled profile corresponding to the instant production of carbon-14.<ref name="usoskin"/>]] | ||
| </div> | |||
| The |
The signal exhibits a sharp increase of around 1.2% followed by a slow decline, which is consistent with an instant production of carbon-14 in the atmosphere,<ref name="usoskin"/> indicating that the event was short in duration. The globally averaged production of ] for this event is {{nowrap|1=(1.3 ± 0.2) × 10{{sup|8}} atoms/cm{{sup|2}}}}.<ref name="usoskin"/><ref name="melott"/><ref name="pavlov"/> | ||
| The globally averaged production of ] for this event is calculated as <big>''Q='' (1.1-1.5)×10<sup>8</sup></big> atoms/cm<sup>2</sup><ref name="usoskin"/><ref name="melott"/><ref name="pavlov"/> | |||
| ==Hypotheses== | ==Hypotheses== | ||
| Several possible |
Several possible causes of the event have been considered. | ||
| The ''Anglo-Saxon Chronicle'' recorded "a red crucifix, after sunset", which has been variously hypothesised to have been a ]<ref name="phys.org red crucifix"/> or the ].<ref name="usoskin"/><ref>{{cite journal |last1=Hayakawa |first1=H. |title=The Celestial Sign in the Anglo-Saxon Chronicle in the 770s: Insights on Contemporary Solar Activity |journal=Solar Physics |volume=294 |issue=4 |pages=42 |year=2019 |arxiv=1903.03075 |bibcode=2019SoPh..294...42H |s2cid=118718677 |doi=10.1007/s11207-019-1424-8}}</ref> | |||
| ⚫ | |||
| ⚫ | Another |
||
| {{Blockquote|text=Annus Domini (the year of the Lord) 774. This year the ] banished their king, ], from ] at Easter-tide; and chose ], for their lord, who reigned four winters. This year also appeared in the heavens a red crucifix, after sunset; the ] and the men of ] fought at ]; and wonderful serpents were seen in the ].|author=|source='']''<ref name="phys.org red crucifix">{{cite web |last=Owano |first=Nancy |title=Red Crucifix sighting in 774 may have been supernova |website=Phys.org |date=2012-06-30 |url=https://phys.org/news/2012-06-red-crucifix-sighting-supernova.html}}</ref>}} | |||
| ==How frequent are such events?== | |||
| The event of 774 is the strongest spike over the last 11 000 years in the record of cosmogenic isotopes,<ref name="usoskin12"/> but it is not unique. A ], but it was a factor of 1.5 weaker.<ref name="miyake14"/> A list of other candidates for other events of the kind during the Holocene can be found in.<ref name="usoskin12"/> | |||
| In China, there is only one clear reference to an aurora in the mid-770s, on 12 January 776.<ref>{{cite journal |last1=Stephenson |first1=F.R. |title=Astronomical evidence relating to the observed {{sup|14}}C increases in A.D. 774–5 and 993–4 as determined from tree rings |journal=Advances in Space Research |volume=55 |issue=6 |pages=1537–45 |year=2015 |bibcode=2015AdSpR..55.1537S |doi=10.1016/j.asr.2014.12.014}}</ref><ref>{{cite journal |last1=Stephenson |first1=F.R. |title=Do the Chinese Astronomical Records Dated AD 776 January 12/13 Describe an Auroral Display or a Lunar Halo? A Critical Re-examination |journal=Solar Physics |volume=294 |issue=4 |pages=36 |year=2019 |arxiv=1903.06806 |bibcode=2019SoPh..294...36S |doi=10.1007/s11207-019-1425-7 |doi-access=free |url=https://centaur.reading.ac.uk/83064/9/Stephenson2019_Article_DoTheChineseAstronomicalRecord.pdf}}</ref> However, an anomalous "thunderstorm" was recorded for 775.<ref>{{cite journal |title=Searching for events in Chinese ancient records to explain the increase in <sup>14</sup>C from 774–775 CE and 993–994 AD |author=Ya-Ting Chai |author2=Yuan-Chuan Zou |name-list-style=amp |year=2015 |journal=Research in Astronomy and Astrophysics |volume=15 |issue=9 |page=1504 |arxiv=1406.7306 |s2cid=124499827 |doi=10.1088/1674-4527/15/9/007}}</ref> | |||
| From this statistics one may expect that such strong events occur once per tens of millennia, while weaker events may occur once per a millennium or even a century. The event of 774 did not cause catastrophic consequences for the life on Earth,<ref name="thomas"/> but if it had happened in modern times, it would produce catastrophic damage to the modern technology, including communication and navigation space-borne systems. | |||
| As established by ] and colleagues,<ref>{{cite journal | |||
| | first1=I.G. | last1=Usoskin | author-link=Ilya G. Usoskin | |||
| | first2=B. | last2=Kromer | |||
| | first3=F. | last3= Ludlow | first4= J. | last4= Beer | |||
| | first5=M. | last5= Friedrich|first6=G.A.|last6= Kovaltsov | |||
| | first7= S.K.| last7= Solanki |first8= L.| last8= Wacker | |||
| |title=The AD775 cosmic event revisited: the Sun is to blame | |||
| | journal = Astronomy and Astrophysics Letters | |||
| | volume=552 |pages=L3 | date= 2013 | |||
| | doi=10.1051/0004-6361/201321080 | |||
| | arxiv=1302.6897}}</ref> the current scientific paradigm<ref>{{cite journal | first1=I.G. | last1=Usoskin | |||
| | author-link=Ilya G. Usoskin |first2=F. |last2= Miyake | |||
| |first3=M. |last3= Baroni | |||
| |display-authors=etal | |||
| |title=Extreme Solar Events: Setting up a Paradigm | |||
| |journal = ] | |||
| |volume=219| pages=73| date= 2023 | |||
| | issue=8 | |||
| |doi=10.1007/s11214-023-01018-1 | |||
| ⚫ | |hdl=20.500.11850/641517|hdl-access=free}}</ref> is that the event was caused by a ] (SPE) from a very strong ], perhaps the strongest known.<ref name="mek15">{{cite journal |date=2015 |author=Mekhaldi |display-authors=etal |journal=Nature Communications |volume=6 |pages=8611 |title=Multiradionuclide evidence for the solar origin of the cosmic-ray events of ᴀᴅ 774/5 and 993/4 |bibcode=2015NatCo...6.8611M |pmid=26497389 |pmc=4639793 |doi=10.1038/ncomms9611}}</ref> | ||
| ⚫ | Another proposed origin, involving a ],<ref name="pavlov"/><ref name="hamb"/> is regarded as unlikely, because the event was also observed in isotopes {{sup|10}}Be and ].<ref name="mek15"/>{{clarify|date=October 2023}} | ||
| ==Frequency of similar events== | |||
| ] | |||
| The event of 774 is the strongest spike over the last 11,000 years in the record of cosmogenic isotopes,<ref name="usoskin12"/> but several other events of the same kind (]s) have occurred during the ] epoch.<ref name="usoskin12"/> The ] was about 60% as strong;<ref name="miyake14"/> another event occurred in {{circa|660 BCE}}.<ref>{{cite journal |last=O'Hare |first=Paschal |display-authors=etal |title=Multiradionuclide evidence for an extreme solar proton event around 2,610 B.P. (~660 BC) |journal=Proceedings of the National Academy of Sciences of the United States of America |volume=116 |issue=13 |pages=5961–6 |date=2019 |doi=10.1073/pnas.1815725116|doi-access=free |bibcode=2019PNAS..116.5961O |pmid=30858311 |pmc=6442557}}</ref><ref>{{cite journal |arxiv=1909.05498 |title=The Earliest Candidates of Auroral Observations in Assyrian Astrological Reports: Insights on Solar Activity around 660 BCE |journal=The Astrophysical Journal |volume=884 |issue=1 |pages=L18 |date=2019 |last1=Hayakawa |first1=Hisashi |last2=Mitsuma |first2=Yasuyuki |last3=Ebihara |first3=Yusuke |last4=Miyake |first4=Fusa |author-link4=Fusa Miyake |bibcode=2019ApJ...884L..18H |s2cid=202565732 |doi=10.3847/2041-8213/ab42e4 |doi-access=free}}</ref> In 2023 the strongest event yet discovered was reported, which occurred in 12,350-12,349 BC.<ref>{{cite journal |display-authors=etal |last1=Edouard Bard |title=A radiocarbon spike at 14 300 cal yr BP in subfossil trees provides the impulse response function of the global carbon cycle during the Late Glacial |journal=Philosophical Transactions of the Royal Society A |date=Oct 9, 2023 |volume=381 |issue=2261 |doi=10.1098/rsta.2022.0206 |pmid=37807686 |pmc=10586540 |bibcode=2023RSPTA.38120206B }}</ref> | |||
| The event of 774 had no significant consequences for life on Earth,<ref name="Sukhodolov17">{{cite journal |last1=Sukhodolov |first1=Timofei |last2=Usoskin |first2=Ilya |last3=Rozanov |first3=Eugene |last4=Asvestari |first4=Eleanna |last5=Ball |first5=William T. |last6=Curran |first6=Mark A. J. |last7=Fischer |first7=Hubertus |last8=Kovaltsov |first8=Gennady |last9=Miyake |first9=Fusa |last10=Peter |first10=Thomas |last11=Plummer |first11=Christopher |last12=Schmutz |first12=Werner |last13=Severi |first13=Mirko |last14=Traversi |first14=Rita |title=Atmospheric impacts of the strongest known solar particle storm of 775 AD |journal=Scientific Reports |volume=7 |issue=1 |pages=45257 |date=March 28, 2017 |issn=2045-2322 |pmid=28349934 |pmc=5368659 |display-authors=1 |bibcode=2017NatSR...745257S |doi=10.1038/srep45257}}</ref><ref name="thomas"/> but had it happened in modern times, it might have produced catastrophic damage to modern technology, particularly to communication and space-borne navigation systems. Also, a solar flare able to produce the observed isotopic effect, would pose considerable risk to astronauts.<ref>{{cite journal |last1=Townsend |first1=L. W.|last2=Porter |first2=J. A.|last3=deWet |first3=W. C |last4=Smith |first4=W. J.|last5=McGirl |first5=N. A.|last6=Heilbronn |first6=L. H.|last7=Moussa |first7=H. M.|date=2016-06-01 |title=Extreme solar event of AD775: Potential radiation exposure to crews in deep space |journal=Acta Astronautica |series=Special Section: Selected Papers from the International Workshop on Satellite Constellations and Formation Flying 2015 |volume=123 |pages=116–120 |bibcode=2016AcAau.123..116T |doi=10.1016/j.actaastro.2016.03.002}}</ref> | |||
| {{sup|14}}C variations are poorly understood, because annual-resolution measurements are available for only a few periods (such as 774–775).<ref name="Miyake17">{{cite journal |pmid=28100493 |volume=114 |issue=5 |title=Large <sup>14</sup>C excursion in 5480 BC indicates an abnormal sun in the mid-Holocene |pmc=5293056 |journal=Proceedings of the National Academy of Sciences of the United States of America |pages=881–4 |last1=Miyake |first1=F. |last2=Jull |first2=A. J. |last3=Panyushkina |first3=I. P. |last4=Wacker |first4=L. |last5=Salzer |first5=M. |last6=Baisan |first6=C. H. |last7=Lange |first7=T. |last8=Cruz |first8=R. |last9=Masuda |first9=K. |last10=Nakamura |first10=T.|bibcode=2017PNAS..114..881M |year=2017 |doi=10.1073/pnas.1613144114 |doi-access=free}}</ref> In a 2017 study, a {{sup|14}}C increase of (2.0%) was associated with a 5480 BC event, but it is not associated with a solar event because of its long duration, but rather to an unusually fast ] of solar activity.<ref name="Miyake17"/> | |||
| ==See also== | ==See also== | ||
| * ], a man-made C-14 spike | |||
| * ] | |||
| * ] | * ] | ||
| ==References== | ==References== | ||
| {{Reflist| |
{{Reflist|30em|refs= | ||
| <ref name="nature"> | <ref name="nature"> | ||
| {{cite journal | {{cite journal | ||
| Line 31: | Line 63: | ||
| |last3=Masuda |first3=K. | |last3=Masuda |first3=K. | ||
| |last4=Nakamura |first4=T. | |last4=Nakamura |first4=T. | ||
| | |
|date=2012 | ||
| |title=A signature of cosmic-ray increase in AD 774–775 from tree rings in Japan | |title=A signature of cosmic-ray increase in AD 774–775 from tree rings in Japan | ||
| |journal=] | |journal=] | ||
| |volume=486 |issue=7402 |pages= |
|volume=486 |issue=7402 |pages=240–2 | ||
| |bibcode=2012Natur.486..240M | |bibcode=2012Natur.486..240M | ||
| |doi=10.1038/nature11123 | |doi=10.1038/nature11123 |pmid=22699615 | ||
| |s2cid=4368820 | |||
| }}</ref> | }}</ref> | ||
| <ref name="usoskin"> | <ref name="usoskin"> | ||
| Line 49: | Line 82: | ||
| |last8=Wacker |first8=L. | |last8=Wacker |first8=L. | ||
| |display-authors=1 | |display-authors=1 | ||
| | |
|date=2013 | ||
| |title=The AD775 cosmic event revisited: The Sun is to blame | |title=The AD775 cosmic event revisited: The Sun is to blame | ||
| |journal=] | |journal=] | ||
| Line 56: | Line 89: | ||
| |bibcode=2013A&A...552L...3U | |bibcode=2013A&A...552L...3U | ||
| |doi=10.1051/0004-6361/201321080 | |doi=10.1051/0004-6361/201321080 | ||
| |s2cid=55137950 | |||
| }}</ref> | }}</ref> | ||
| <ref name="thomas"> | <ref name="thomas"> | ||
| Line 63: | Line 97: | ||
| |last3=Arkenberg |first3=K. R. | |last3=Arkenberg |first3=K. R. | ||
| |last4=Snyder |first4=B. R. | |last4=Snyder |first4=B. R. | ||
| | |
|date=2013 | ||
| |title=Terrestrial effects of possible astrophysical sources of an AD |
|title=Terrestrial effects of possible astrophysical sources of an AD 774–775 increase in <sup>14</sup>C production | ||
| |journal=] | |journal=] | ||
| |volume=40 |issue=6 |pages=1237 | |volume=40 |issue=6 |pages=1237 | ||
| |arxiv=1302.1501 | |arxiv=1302.1501 | ||
| |bibcode=2013GeoRL..40.1237T | |bibcode=2013GeoRL..40.1237T | ||
| |doi=10.1002/grl.50222 |
|doi=10.1002/grl.50222 | ||
| |s2cid=14253803 | |||
| }}</ref> | }}</ref> | ||
| <ref name="guettler"> | <ref name="guettler"> | ||
| {{cite |
{{cite book | ||
| |last1 |
|last1=Güttler |first1=D. | ||
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|last2=Beer |first2=J. | ||
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|last3=Bleicher |first3=N. | ||
| | |
|chapter=The 774/775 AD event in the southern hemisphere | ||
| |title=ETH-Zurich: Laboratory of Ion Beam Physics: Annual Report 2013 | |||
| |journal = Annual report of the laboratory of ion beam physics, | |||
| | |
|date=2013 |page=33 | ||
| |publisher = |
|publisher=LIBRUM |isbn=9783952403846 |oclc=887695262 | ||
| }}</ref> | }}</ref> | ||
| <ref name="jull"> | <ref name="jull"> | ||
| {{cite journal | {{cite journal | ||
| |last1 |
|last1=Jull |first1=A.J.T. | ||
| |last2 |
|last2=Panyushkina |first2=I.P. | ||
| |last3 |
|last3=Lange |first3=T.E. | ||
| |display-authors |
|display-authors=etal | ||
| |title |
|title=Excursions in the 14C record at AD 774–775 in tree rings from Russia and America | ||
| |journal |
|journal=Geophys. Res. Lett. | ||
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|volume=41 | ||
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|doi=10.1002/2014GL059874 | ||
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| <ref name="pavlov"> | <ref name="pavlov"> | ||
| {{ |
{{cite journal | ||
| |last1 |
|last1=Pavlov |first1=A.K. | ||
| |last2 |
|last2=Blinov |first2=A.V. | ||
| |last3 |
|last3=Konstantinov |first3=A.N. | ||
| |display-authors |
|display-authors=etal | ||
| |title |
|title=AD 775 pulse of cosmogenic radionuclides production as imprint of a Galactic gamma-ray burst | ||
| |journal |
|journal=Mon. Not. R. Astron. Soc. | ||
| | |
|date=2013 | ||
| |volume |
|volume=435 | ||
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|pages=2878–2884 | ||
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|doi=10.1093/mnras/stt1468 | ||
| ⚫ | |arxiv |
||
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| <ref name="melott"> | <ref name="melott"> | ||
| {{cite journal | {{cite journal | ||
| |last1 |
|last1=Melott |first1=A.L. | ||
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|last2=Thomas |first2=B.C. | ||
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|title=Causes of an AD 774-775 <sup>14</sup>C increase | ||
| |journal |
|journal=Nature | ||
| | |
|date=2012 | ||
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|volume=491 | ||
| |issue=7426 | |||
| |pages |
|pages=E1–E2 | ||
| |doi |
|doi=10.1038/nature11695 | ||
| |arxiv |
|arxiv=1212.0490 |bibcode=2012Natur.491E...1M |pmid=23192153|s2cid=205231715 | ||
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| <ref name="miyake14"> | <ref name="miyake14"> | ||
| {{cite journal | {{cite journal | ||
| |last1 |
|last1=Miyake |first1=F. | ||
| |last2 |
|last2=Masuda |first2=K. | ||
| |last3 |
|last3=Nakamura |first3=T. | ||
| |title |
|title=Another rapid event in the carbon-14 content of tree rings | ||
| |journal |
|journal=Nature Communications | ||
| | |
|date=2013 | ||
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|volume=4 | ||
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| <ref name="usoskin12"> | <ref name="usoskin12"> | ||
| {{cite journal | {{cite journal | ||
| |last1 |
|last1=Usoskin |first1=I.G. | ||
| |last2 |
|last2=Kovaltsov |first2=G.A. | ||
| |title |
|title=Occurrence of Extreme Solar Particle Events: Assessment from Historical Proxy Data | ||
| |journal |
|journal=Astrophys. J. | ||
| |arxiv |
|arxiv=1207.5932 | ||
| | |
|date=2012 | ||
| |volume |
|volume=757 | ||
| |issue=1 | |||
| |pages = 92 | |||
| |doi |
|pages=92 | ||
| |doi=10.1088/0004-637X/757/1/92 | |||
| |bibcode |
|bibcode=2012ApJ...757...92U |s2cid=56189671 | ||
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| <ref name="hamb"> | <ref name="hamb"> | ||
| Line 147: | Line 193: | ||
| |last1=Hambaryan |first1=V. V. | |last1=Hambaryan |first1=V. V. | ||
| |last2=Neuhauser |first2=R. | |last2=Neuhauser |first2=R. | ||
| | |
|date=2013 | ||
| |title=A Galactic short gamma-ray burst as cause for the |
|title=A Galactic short gamma-ray burst as cause for the {{sup|14}}C peak in AD 774/5 | ||
| |journal=] | |journal=] | ||
| |volume=430 |issue=1 |pages=32–36 | |volume=430 |issue=1 |pages=32–36 | ||
| Line 154: | Line 200: | ||
| |bibcode=2013MNRAS.430...32H | |bibcode=2013MNRAS.430...32H | ||
| |doi=10.1093/mnras/sts378 | |doi=10.1093/mnras/sts378 | ||
| |doi-access=free | |||
| }}</ref> | }}</ref> | ||
| }} | }} | ||
| ==External links== | ==External links== | ||
| * {{YouTube|inIFO5ZvdqM|Gamma Ray Burst of 775 (Dec 3, 2014). SciShow Space.}} | |||
| * | |||
| {{Solar storms}} | {{Solar storms}} | ||
| {{DEFAULTSORT:774-775 carbon-14 spike}} | |||
| ⚫ | ] | ||
| ⚫ | ] | ||
| ] | ] | ||
| ⚫ | ] | ||
| ⚫ | ] | ||
| ] | |||
| ] | |||
| ] | |||
Latest revision as of 00:43, 13 October 2024
Observed increase concentration of carbon-14 in tree rings dated 774 or 775The 774–775 carbon-14 spike is an observed increase of around 1.2% in the concentration of the radioactive carbon-14 isotope in tree rings dated to 774 or 775 CE, which is about 20 times higher than the normal year-to-year variation of radiocarbon in the atmosphere. It was discovered during a study of Japanese cedar tree-rings, with the year of occurrence determined through dendrochronology. A surge in beryllium-10 (Be), detected in Antarctic ice cores, has also been associated with the 774–775 event. The 774–775 CE carbon-14 spike is one of several Miyake events and it produced the largest and most rapid rise in carbon-14 ever recorded.
The event appears to have been global, with the same carbon-14 signal found in tree rings from Germany, Russia, the United States, Finland, and New Zealand.
The signal exhibits a sharp increase of around 1.2% followed by a slow decline, which is consistent with an instant production of carbon-14 in the atmosphere, indicating that the event was short in duration. The globally averaged production of carbon-14 for this event is (1.3 ± 0.2) × 10 atoms/cm.
Hypotheses
Several possible causes of the event have been considered.
The Anglo-Saxon Chronicle recorded "a red crucifix, after sunset", which has been variously hypothesised to have been a supernova or the aurora borealis.
Annus Domini (the year of the Lord) 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.
— Anglo-Saxon Chronicle
In China, there is only one clear reference to an aurora in the mid-770s, on 12 January 776. However, an anomalous "thunderstorm" was recorded for 775.
As established by Ilya G. Usoskin and colleagues, the current scientific paradigm is that the event was caused by a solar particle event (SPE) from a very strong solar flare, perhaps the strongest known. Another proposed origin, involving a gamma-ray burst, is regarded as unlikely, because the event was also observed in isotopes Be and Cl.
Frequency of similar events
The event of 774 is the strongest spike over the last 11,000 years in the record of cosmogenic isotopes, but several other events of the same kind (Miyake events) have occurred during the Holocene epoch. The 993–994 carbon-14 spike was about 60% as strong; another event occurred in c. 660 BCE. In 2023 the strongest event yet discovered was reported, which occurred in 12,350-12,349 BC.
The event of 774 had no significant consequences for life on Earth, but had it happened in modern times, it might have produced catastrophic damage to modern technology, particularly to communication and space-borne navigation systems. Also, a solar flare able to produce the observed isotopic effect, would pose considerable risk to astronauts.
C variations are poorly understood, because annual-resolution measurements are available for only a few periods (such as 774–775). In a 2017 study, a C increase of (2.0%) was associated with a 5480 BC event, but it is not associated with a solar event because of its long duration, but rather to an unusually fast grand minimum of solar activity.
See also
- Bomb pulse, a man-made C-14 spike
- Carrington Event
- List of solar storms
References
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