© Reeth Informal Astronomy Group unless otherwise indicated
Reeth Informal
Astronomy Group
covering the Northern Yorkshire Dales
Recently a significant, short term, increase in C-14 was found in tree rings in Japanese Cedar world-wide for the years 774-5. A surge in Be, Al and Cl was subsequently found in Antarctic ice cores. Originally thought to be due to cosmic rays from a supernova but now the anomaly is believed to be from a solar flare, the largest known to date.
The contemporary Anglo Saxon Chronicle has the following entry for that year:
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.
This suggests highly visible aurora even as far south as southern England. Strangely the Chinese astronomers make no mention of the event.
Subsequently another large event was found in ice cores for the year 660 BCE.
Such storms happening in an electronic age could have very significant impacts. The largest such event was the Carrington Event of 1859 which knocked out telegraph systems across North America and Europe and caused some electrical fires. Lloyds of London have estimated that such an event today would cause damage between 0-6-2.6 trillion dollars. It is a good job therefore that the Carrington-sized event recorded by satellites in 2012 missed the Earth!
A large event in 1969 knocked the power system out in Quebec, but perhaps the scariest event occurred in late May 1967 which caused a blackout of US polar surveillance radars leading to the expectation of an imminent nuclear attack. This makes the event of August 1972, which lead to the detonation of numerous magnetic influence sea mines, seem almost trivial.
If you are interested there are many web sites dedicated to ‘space weather’ where you can find out more.