Earth missed a potentially catastrophic encounter with a solar storm by one week in 2012, physicists report.
"I have come away from our recent studies more convinced than ever that Earth and its inhabitants were incredibly fortunate that the 2012 eruption happened when it did," physicist Daniel Baker of the University of Colorado said in a NASA Science online release. "If the eruption had occurred only one week earlier, Earth would have been in the line of fire."
On July 23, 2012, the sun unleashed two massive clouds of plasma that barely missed a catastrophic encounter with the Earth's atmosphere. These plasma clouds, known as coronal mass ejections (CMEs), comprised a solar storm thought to be the most powerful in at least 150 years.
"If it had hit, we would still be picking up the pieces," Baker said.
Fortunately, the blast site of the CMEs was not directed at Earth. Had this event occurred a week earlier when the point of eruption was Earth-facing, the outcome could have been disastrous.
A CME double whammy of this potency striking Earth would probably cripple satellite communications and could severely damage the power grid. NASA offers this sobering assessment:
"Analysts believe that a direct hit . . . could cause widespread power blackouts, disabling everything that plugs into a wall socket. Most people wouldn't even be able to flush their toilet because urban water supplies largely rely on electric pumps. . . . According to a study by the National Academy of Sciences, the total economic impact could exceed $2 trillion or 20 times greater than the costs of a Hurricane Katrina. Multi-ton transformers damaged by such a storm might take years to repair."
Steve Tracton of The Washington Post's Capital Weather Gang put it this way in an overview of the risks of a severe solar storm: "The consequences could be devastating for commerce, transportation, agriculture and food stocks, fuel and water supplies, human health and medical facilities, national security, and daily life in general."
Solar physicists compare the 2012 storm to the Carrington solar storm of September 1859, named after English astronomer Richard Carrington, who documented the event.
"In my view the July 2012 storm was in all respects at least as strong as the 1859 Carrington event," Baker told NASA. "The only difference is, it missed."
During the Carrington event, the northern lights were seen as far south as Cuba and Hawaii, according to historical accounts. The solar eruption "caused global telegraph lines to spark, setting fire to some telegraph offices," NASA noted.
NASA said the July 2012 storm was particularly intense because a CME had traveled along the same path just days before the July 23 double whammy -- clearing the way for maximum effect, like a snowplow.
"This double-CME traveled through a region of space that had been cleared out by yet another CME four days earlier," NASA said. " As a result, the storm clouds were not decelerated as much as usual by their transit through the interplanetary medium."
NASA said there is a 12 percent chance of a Carrington-type event on Earth in the next 10 years, according to Pete Riley of Predictive Science.
"Initially, I was quite surprised that the odds were so high, but the statistics appear to be correct," Riley told NASA. "It is a sobering figure."