The 993–994 carbon-14 spike was a rapid 0.91% increase in
carbon-14
Carbon-14, C-14, C or radiocarbon, is a radioactive isotope of carbon with an atomic nucleus containing 6 protons and 8 neutrons. Its presence in organic matter is the basis of the radiocarbon dating method pioneered by Willard Libby and coll ...
isotope content from tree rings dated 993–994 CE.
This event was also confirmed with an associated increase of
beryllium-10
Beryllium-10 (10Be) is a radioactive isotope of beryllium. It is formed in the Earth's atmosphere mainly by cosmic ray spallation of nitrogen and oxygen. Beryllium-10 has a half-life of 1.39 million years, and decays by beta decay to stable bor ...
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 and 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
Dendrochronology (or tree-ring dating) is the scientific method of chronological dating, dating tree rings (also called growth rings) to the exact year they were formed in a tree. As well as dating them, this can give data for dendroclimatology, ...
(tree-ring studies) to precisely determine that
Vikings
Vikings were seafaring people originally from Scandinavia (present-day Denmark, Norway, and Sweden),
who from the late 8th to the late 11th centuries raided, pirated, traded, and settled throughout parts of Europe.Roesdahl, pp. 9â ...
were present in
L'Anse aux Meadows
L'Anse aux Meadows () is an archaeological site, first excavated in the 1960s, of a Norse colonization of North America, Norse settlement dating to approximately 1,000 years ago. The site is located on the northernmost tip of the island of Newf ...
in
Newfoundland
Newfoundland and Labrador is the easternmost province of Canada, in the country's Atlantic region. The province comprises the island of Newfoundland and the continental region of Labrador, having a total size of . As of 2025 the population ...
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
Korea is a peninsular region in East Asia consisting of the Korean Peninsula, Jeju Island, and smaller islands. Since the end of World War II in 1945, it has been politically Division of Korea, divided at or near the 38th parallel north, 3 ...
,
Germany
Germany, officially the Federal Republic of Germany, is a country in Central Europe. It lies between the Baltic Sea and the North Sea to the north and the Alps to the south. Its sixteen States of Germany, constituent states have a total popu ...
and
Ireland
Ireland (, ; ; Ulster Scots dialect, Ulster-Scots: ) is an island in the North Atlantic Ocean, in Northwestern Europe. Geopolitically, the island is divided between the Republic of Ireland (officially Names of the Irish state, named Irelan ...
, usually describing a red sky, presumably because of major auroras.
The historical observations do not completely prove the cause of the 993–994 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
Korea is a peninsular region in East Asia consisting of the Korean Peninsula, Jeju Island, and smaller islands. Since the end of World War II in 1945, it has been politically divided at or near the 38th parallel between North Korea (Dem ...
, between December 992 and January 993, a text described "heaven's gate" opening one night.
In the
Saxony
Saxony, officially the Free State of Saxony, is a landlocked state of Germany, bordering the states of Brandenburg, Saxony-Anhalt, Thuringia, and Bavaria, as well as the countries of Poland and the Czech Republic. Its capital is Dresden, and ...
region of present-day
Germany
Germany, officially the Federal Republic of Germany, is a country in Central Europe. It lies between the Baltic Sea and the North Sea to the north and the Alps to the south. Its sixteen States of Germany, constituent states have a total popu ...
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
Ulster (; or ; or ''Ulster'') is one of the four traditional or historic provinces of Ireland, Irish provinces. It is made up of nine Counties of Ireland, counties: six of these constitute Northern Ireland (a part of the United Kingdom); t ...
region of present-day
Northern Ireland
Northern Ireland ( ; ) is a Countries of the United Kingdom, part of the United Kingdom in the north-east of the island of Ireland. It has been #Descriptions, variously described as a country, province or region. Northern Ireland shares Repub ...
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 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 spikes, which further proves that they are from strong solar activity.
See also
*
List of solar storms
Solar storms of different types are caused by disturbances on the Sun, most often from coronal mass ejections (CMEs) and solar flares from active regions, or, less often, from coronal holes. Minor to active solar storms (i.e. storming restrict ...
*
774–775 carbon-14 spike
*
Miyake event
A Miyake event is an observed sharp enhancement of the production of Cosmogenic nuclide, cosmogenic isotopes by cosmic rays. It can be marked by a spike in the concentration of radioactive carbon isotope Carbon-14, in tree rings, as well as Beryl ...
References
{{DEFAULTSORT:993-994 carbon-14 spike
Geomagnetic storms
Dendrology
Stratigraphy
Carbon-14
993
994