The Solar Super Storm

This was the date, in 1859, of a massive solar superstorm. It's sometimes called the "perfect space storm" or the Carrington Event, after British astronomer Richard Carrington. He reported witnessing a massive white-light solar flare: a bright spot suddenly appearing on the surface of the Sun. At the same time, the Sun produced a coronal mass ejection, or CME: a large eruption of magnetized plasma. CMEs usually take three to four days to reach Earth, but the magnetic burst from the superstorm of 1859 reached us in just under 18 hours.

While Earthlings of 1859 didn't have any cell phones, GPS units, or television signals to worry about, they were growing accustomed to rapid communication over the telegraph, which had been in use for 15 years. Within hours of the CME, telegraph wires began shorting out, starting fires and disrupting communication in North America and Europe. Compasses were useless because the Earth's magnetic field had gone haywire. The northern lights were seen as far south as Cuba and Hawaii, and the southern lights — aurora australis — were seen in Santiago, Chile. People in the northeastern United States could read the newspaper by the light of the aurora, and the Sun itself was twice as bright during the event.

Subsequent solar storms have caused satellites, broadcast stations, and cell phones to malfunction; they've disrupted GPS systems on airplanes and have even knocked out entire power grids; in 1989, a storm much weaker than the superstorm of 1859 brought down the Hydro-Quebec power grid for more than nine hours. While scientists cannot predict the storms with any degree of confidence, some speculate that the Sun is expected to reach a period of peak activity in 2013, and the large flares often follow the peak periods. They're monitoring the Sun's activity closely, because with a little advance warning, power grids could be taken offline and satellites put in "sleep" mode for the duration of the storm, averting a global catastrophe from which it could take a decade and trillions of dollars to recover. 

(From "The Writers Almanac")