The geomagnetic storm of 1859

Sunspots September 1, 1859 , sketch by Richard Carrington

The geomagnetic storm of 1859 is the most powerful geomagnetic storm in the history of observations. The set of events, which includes both a geomagnetic storm and powerful active phenomena on the Sun that caused it, is sometimes called the Carrington Event ^[1] or, following the English language literature, the Solar Superstorm ^[2] .

From August 28 to September 2, numerous sunspots and flares were observed on the Sun. Immediately after noon on September 1, the British astronomer Richard Carrington observed the largest flare ^[3] , which caused a large coronal mass ejection . He rushed to the Earth and reached it after 18 hours, which is very fast, since this distance is usually covered by an ejection in 3-4 days. The release moved so fast because previous emissions cleared its path ^[4] .

September 1–2, the largest geomagnetic storm in the entire history of registration began, which caused the failure of telegraph systems throughout Europe and North America ^[5] . Northern lights were observed all over the world, even over the Caribbean ; it is also interesting that over the Rocky Mountains they were so bright that the glow woke the gold diggers, who began to cook breakfast, thinking that it was morning ^[3] . According to the first estimates, the Dst-index of geomagnetic activity (Eng. Disturbance Storm Time Index ) during the storm reached −1760 nT ^[6] . Extrapolation of available measurements of the Dst index to the region of extreme storms shows that storms with Dst = −1760 nT occur on Earth no more than 1 storm in 500 years ^[7] . However, it should be noted that serious arguments are expressed in the scientific literature that, due to methodological problems in analyzing data of a century and a half ago, the estimate Dst = −1760 nT was found to be too high, and the magnitude of the storm was no more than −900 nT ^{[8] [9]} .

Ice cores indicate that events of this intensity recur on average about once every 500 years. The strongest storm since the beginning of the space era (since 1957) occurred on March 13, 1989 , when the Dst-index of geomagnetic activity reached −640 nT ^[6] . Also after 1859, less severe storms occurred in 1921 and 1960 , when there were massive interruptions in radio communications ^[3] .