In May 1921, people all over the world read in the newspapers about a mysterious power failure in many countries, including the telegraph. At that time, they did not know that the cause of the incident was the largest magnetic storm of the twentieth century.
On 12 May, a huge sunspot formed on the Sun. The most powerful coronal mass ejection rushed towards our planet. The Earth’s magnetic field literally “shook” for three days.
Then fires began to appear. On 15 May, a telegraph office in Sweden caught fire. About an hour later a fire was reported in Brewster (New York), where the fire eventually consumed the entire building.
Induced currents began to critically heat telephone and telegraph lines, destroying communications systems in the US, Australia, New Zealand, Japan, France, Norway, Sweden, Denmark, and the UK.
Voltage jumped to thousands of volts on a number of lines in the US.
The peak of the storm on 15 May caused northern lights in Los Angeles, Atlanta, Texas.
Researchers Mike Hapgood and Jeffrey Love painstakingly searched historical records, trying to calculate the so-called storm disturbance time index (Dst). They managed to find a few magnetometer records that were not out of scale at the time (the feathers of most recorders at this point just hovered helplessly at the edge of the tape). Using this data, the scientists identified the desired parameter.
