Solar storm of 2012
The solar storm of 2012 was an unusually large and strong coronal mass ejection (CME) event that occurred on July 23 that year. It missed the Earth with a margin of approximately nine days, as the equator of the Sun rotates around its own axis with a period of about 25 days. The region that produced the outburst was thus not pointed directly towards the Earth at that time. The strength of the eruption was comparable to the 1859 Carrington event that caused damage to electric equipment worldwide, which at that time consisted mostly of telegraph stations.
The eruption tore through Earth's orbit, hitting the STEREO-A spacecraft. The spacecraft is a solar observatory equipped to measure such activity, and because it was far away from the Earth and thus not exposed to the strong electrical currents that can be induced when a CME hits the Earth's magnetosphere, it survived the encounter and provided researchers with valuable data.
Based on the collected data, the eruption consisted of two separate ejections which were able to reach exceptionally high strength as the interplanetary medium around the Sun had been cleared by a smaller CME four days earlier. Had the CME hit the Earth, it is likely that it would have inflicted serious damage to electronic systems on a global scale. A 2013 study estimated that the economic cost to the United States would have been between $0.6 and 2.6 trillion USD. Ying D. Liu, professor at China's State Key Laboratory of Space Weather, estimated that the recovery time from such a disaster would have been about four to ten years.
The record fastest CME associated with the solar storm of August 1972 is thought to have occurred in a similar process of earlier CMEs clearing particles in the path to Earth. This storm arrived in 14.6 hours, an even shorter duration after the parent flare erupted than for the great solar storm of 1859.
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