The National Aeronautics and Space Administration revealed that the Earth was just barely missed by a massive solar storm two years ago, which was the strongest one in over 150 years.
A study on the solar storm entitled "A major solar eruptive event in July 2012" was published in the Space Weather journal in December of last year by Baker and colleagues from other universities and NASA.
"If it had hit, we would still be picking up the pieces," said Daniel Baker from the University of Colorado.
The study described the immense power behind the solar storm, which actually entered the orbit of the Earth on July 23, 2012.
Extreme solar storms are dangerous to all kinds of technology. The storms begin with a solar flare that sends X-rays and ultraviolet radiation to Earth which can cause a solar electromagnetic pulse that can lead to radio blackouts and scrambled GPS navigation systems. After a few minutes or hours, energetic particles of accelerated protons and electrons will reach the Earth, electrifying and damaging satellite systems. A coronal mass ejection then follows, which are billion-ton magnetized plasma clouds that take at least a day to reach the Earth from the Sun.
The study reports that if the CME that was released by the solar storm in 2012 had hit the Earth, the impact would have caused widespread power outages.
The last instance of such an extreme solar storm was recorded in September 1859, when very strong CMEs hit the planet head on, causing global telegraph connections to spark, which set fire to several telegraph offices.
The phenomenon is known as the Carrington Event, named after an English astronomer named Richard Carrington who observed the solar flare that caused the storm.
Such a storm hitting the Earth today would be more catastrophic, considering the society's much higher reliance on electricity today than in the past.
The National Academy of Sciences said that if the Earth was hit by a powerful CME, the total economic damage caused would be more than $2 trillion.
"We would have been well and truly pushed back to the Stone Age for days," said Swinburne University astrophysicist Alan Duffy.
It is fortunate then that the CME reached Earth when it did, as the storm cloud was off the side and only hit the STEREO-A spacecraft. If the storm was a week earlier, Earth would have suffered the consequences.
The storm cloud hitting STEREO-A was a lucky coincidence, as the spacecraft is perfectly equipped to study and analyze the event.
"Thanks to STEREO-A we know a lot of about the magnetic structure of the CME, the kind of shock waves and energetic particles it produced, and perhaps most importantly of all, the number of CMEs that preceded it," said Pete Riley from Predictive Science Inc.