On September 1, 1859, English astronomer Richard Carrington saw sunspots through his telescope, from which “two patches of intensely bright and white light” shot outward.
Though not fully understood at the time, Carrington had become the first person to view a solar flare, what's now called a coronal mass ejection or CME. A solar storm was hitting the Earth. It came in two disruptive waves.
That evening, telegraph lines were again disrupted, this time more profoundly and at locations worldwide. Chemical-marked papers in telegraph offices combusted suddenly and many telegraph operators received electrical shocks from equipment.
In North America, auroras shone so as far south as Cuba and so red and brightly that in the Carolinas birds began to sing thinking it was dawn and in Boston people could read by the light.
On the July 23, 2012 a "Carrington-class" Solar Superstorm (CEM/Solar EMP) just barely missed the Earth. NASA didn't share the information publicly about the near-miss until April 2014.
What are the chances another solar storm like the one causing the Carrington Event will impact us in the next ten years? Here's the best guess so far:
In February 2014, physicist Pete Riley of Predictive Science Inc. published a paper in Space Weather entitled "On the probability of occurrence of extreme space weather events." In it, he analyzed records of solar storms going back 50+ years. By extrapolating the frequency of ordinary storms to the extreme, he calculated the odds that a Carrington-class storm would hit Earth in the next ten years. The answer: 12%.
What would be the effect on our highly technology-driven society? It's hard to say, but in July of 2014, researcher Daniel Baker of the University of Colorado said that if the July 2012 CME had hit Earth, "we would still be picking up the pieces."