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induced by the geomagnetic storm (Silverman 2001). It has been estimated that if an event like
that one occurred today, in the United States alone it would put over 350 main-grid trans-
formers at risk of serious damage, potentially knocking out power to over 130 million Americ-
ans.
The Carrington Event
The great geomagnetic solar storm of 1859 was actually a combination of two closely spaced,
massive solar-induced worldwide geomagnetic events, the first one beginning on August 28
and the second one on September 2. From August 28 to September 4, much of the world was
dazzled by an “otherworldly” array of brilliant nighttime light shows. Hikers in the Rocky
Mountains were awakened in the middle of the night thinking it was morning. A “perfect dome
of alternate red and green streamers” was observed over New England, and citizens in Havana,
Cuba, described the sky as appearing “stained with blood and in a state of general conflagra-
tion.” More pertinent to the concerns of this topic, telegraph systems around the world experi-
enced major outages and disruptions. In some cases telegraph poles and stations caught on fire,
and in others telegraph operators disconnected their batteries and sent telegraph messages using
only the electromagnetically induced currents produced by the solar storm's aurora.
On September 1, 1859, the British amateur astronomer, Richard Carrington, observed “two
patches of intensely bright and white light” ejecting from a large complex of sunspots located
near the center of the side of the sun facing the earth. Carrington noted that this outburst was
followed by a severe magnetic storm that hit the earth the following day. It was not until the
1970s that scientists realized it was the coronal mass ejections (CMEs), and not eruptive flares,
that are the cause of non-recurrent solar-induced geomagnetic storms. It turns out that when
masses of large solar particles reach the earth as a result of CMEs, they leave a “fingerprint” in
the form of nitrates that are created in the upper atmosphere and settle out over the following
weeks. These nitrates are stored in arctic ice layers, providing scientists with a record and com-
parison of the magnitude and chronology of prior solar super storms, such as the Carrington
Event.
Ice-core-sample analysis indicates that the Carrington Event was the most powerful geo-
magnetic event in at least the prior 500 years, and best estimates are that the Carrington Event
was stronger than the solar super storm of May 1921 by 50 percent or more.
Disruptions Caused by Aboveground Nuclear Tests
