A solar storm in July 2012 barely missed the Earth, and this massive discharge from the sun could have sent our species back to the 19th century, at least for a while.
On 22 July 2012, the Solar and Heliospheric Observatory (SOHO), managed by NASA, observed a tremendous solar flare erupting from the sun. This flare blasted off the surface of the sun at one of the highest velocities ever witnessed, nearly 5.6 million miles per hour. It was detected reaching Earth's orbit just 19 hours after the eruption, while normal times for such journeys are around three to four days. Astronomers believe this storm may have been the most powerful flare produced in 150 years.
The STEREO-A spacecraft, launched in 2006 on a mission to observe the sun, was hit by the outburst from our stellar companion. If the event had taken place just one week earlier, Earth would have been directly in line with the blast from the massive flare.
Researchers studied what would have happened if the flare had been directed at our home world. They used a well-known geomagnetic storm forecast model to develop their model.
"If it had hit, we would still be picking up the pieces... If the eruption had occurred only one week earlier, Earth would have been in the line of fire," Daniel Baker from the University of Colorado, told reporters.
The Carrington Event was the most powerful solar flare to strike the Earth in the modern age. On 1 September 1859, astronomer Richard Carrington was observing sunspots when he observed a massive solar flare erupting from the solar surface. The coronal mass ejection (CME), a burst of solar wind wrapped in a magnetic field, raced toward the Earth, reaching our home planet in less than 18 hours.
Once the CME struck the Earth, it caused aurora around the world - the northern lights were seen as far south as the Caribbean. In New England, the display was so bright. It was possible to read a newspaper that night by their glow.
Telegraphs failed in a spectacular fashion - operators were shocked by the devices, and some machines continued to operate, even after being disconnected from electricity.
In June 2013, insurance giant Lloyds of London estimated a similar event today would devastate electronics, and cause over 2.6 trillion dollars. Baker and his team believe the 2012 event was at least as powerful as the 1859 eruption.
One of the great dangers of CME's is the way they can interact with the magnetic field of the Earth, producing dangerous electric currents. Out in space where STEREO-A orbits the sun; magnetic fields are much weaker, reducing the effect of the storm on the spacecraft, which remained unharmed.
Researchers led by Baker described the stellar event in a 2013 article published in the journal Space Weather.
