Carrington Event

The Carrington Event was the most intense geomagnetic storm in recorded history, peaking from 1 to 2 September 1859 during solar cycle 10. It created strong auroral displays that were reported globally and caused sparking and even fires in multiple telegraph stations. The geomagnetic storm was most likely the result of a coronal mass ejection (CME) from the Sun colliding with Earth's magnetosphere. The geomagnetic storm was associated with a very bright solar flare on 1 September 1859. It was observed and recorded independently by British astronomers Richard Christopher Carrington and Richard Hodgson—the first records of a solar flare. A geomagnetic storm of this magnitude occurring today would cause widespread electrical disruptions, blackouts, and damage due to extended outages of the electrical power grid. On 1–2 September 1859, one of the largest geomagnetic storms (as recorded by ground-based magnetometers) occurred. Estimates of the storm strength (Dst) range from −0.80 to −1.75 μT. The geomagnetic storm is thought to have been initiated by a major CME that traveled directly toward Earth, taking 17.6 hours to make the journey. Typical CMEs take several days to arrive at Earth, but it is believed that the relatively high speed of this CME was made possible by a prior CME, perhaps the cause of the large aurora event on 29 August that "cleared the way" of ambient solar wind plasma for the Carrington Event. Just before noon on 1 September, the English amateur astronomers Richard Christopher Carrington and Richard Hodgson independently recorded the earliest observations of a solar flare. Carrington and Hodgson compiled independent reports which were published side by side in Monthly Notices of the Royal Astronomical Society and exhibited their drawings of the event at the November 1859 meeting of the Royal Astronomical Society. Because of a geomagnetic solar flare effect (a "magnetic crochet") observed in the Kew Observatory magnetometer record by Scottish physicist Balfour Stewart, and a geomagnetic storm observed the following day, Carrington suspected a solar-terrestrial connection.