In 2012, one of the largest solar flares ever recorded came close to causing havoc with electricity networks on Earth and the odds of such an event in the coming decade may be as great as 12 percent, scientists say.
The 2012 solar storm, known as a coronal mass ejection, was fortunately from a part of the sun's surface that was pointing away from our planet; had it been aimed our way, it could have created the most serious geomagnetic disturbance in more than 400 years and resulted in serious disruptions of our electrical infrastructure, they say.
If the storm had erupted just one week earlier, the Earth could have been in the bull's-eye with billions of tons of highly energetic solar particles racing toward our planet's magnetic field with speeds of 1,500 mph, says Daniel N. Baker of the University of Colorado's Laboratory for Atmospheric and Space Physics.
The result could have been similar to that of a massive 1859 solar storm, named the Carrington Event for the English amateur astronomer who first witnessed it.
That event caused northern lights to be seen as far south as Cuba and caused sparking in telegraph lines -- that era's high-tech infrastructure -- setting off fires in some buildings.
"According to data from the STEREO-A spacecraft (a solar observatory), the solar storm of July 23, 2012, was every bit as potent as the Carrington storms," says Baker, the author of a study in the journal Space Weather on the 2012 storm.
If directed at Earth the storm could have caused disruptions to the globe's electricity grid that might leave people in the dark for months and possible even years.
Advance warning of a solar storm headed our way would be no more than hours, the researchers said in the journal article.
"The July 2012 solar storm was a shot across the bows for policymakers and space weather professionals," they wrote.
If the storm's timing had been just a bit earlier the Earth would have been directly in the firing line of an unprecedentedly significant space weather event with possibly dire effects for our advanced technology society, they said.
"There is a legitimate question of whether our society would still be picking up the pieces," they wrote.
In 2008, the U.S. National Academy of Sciences issued a report saying even a moderately severe solar stormed aimed directly at the Unites States could have the potential of leaving 130 million people without power.
Predicted damage to more than 300 high-voltage transformers would need months to repair, the report said.
And the risk increases as we become dependent on ever-more sophisticated technology, says Tony Phillips, editor of Science@NASA.
"As society relies more and more on high technology such as GPS, the Internet, satellite communications and smart power grids, we also expose ourselves more and more to the dangers of stormy space weather," he says.