Earlier today the earth was struck by the largest Coronal Mass Ejection (CME) since 2005. Although it caused no damage, one much larger could wreak havoc on the surface of the earth, disrupting the electric grid, radio signals and GPS. With the Sun set to become even more active in the next few years as it follows it’s 11 year activity cycle, our little planet seems ever more vulnerable. A storm as large as those in 1921 or 1859 could cause power blackouts for months and inflict trillions of pounds of damage.

CME’s are the product of the wildly fluctuating magnetic fields that cover the surface of the Sun. When opposing magnetic field lines converge the energy released can fling a portion of the Sun’s atmosphere out into space. The coronal ejection is composed of a fast moving wave of high energy electromagnetic radiation and billions of tonnes of slower subatomic particles, hydrogen, helium and iron. CME’s and their smaller cousins, solar flares, are most often produced from areas of sunspots.

At low levels, these showers of plasma and radiation can cause little harm. The magnetised particles hit ions trapped in the earth’s own magnetic field and emit light. The constant low levels of solar ejecta produced by the sun is what gives us the Auroras borealis and australis. But when a CME hits the earth, its defences are overloaded and a geomagnetic storm begins.

The magnetic force of the wave of plasma causes fluctuations in the earth’s magnetic field. Just like a dynamo that uses a magnet to induce electricity, the changing magnetic field can generate electricity in anything capable of conducting it. For the last century we have been building national systems for doing exactly that. The earth’s surface is covered in metal pipelines, electricity pylons and phonelines, it makes the surface of the earth a lightning rod for the vast amounts of energy being pumped out from the sun.

When a huge geomagnetic storm hit the earth in 1859, telegraph operators were reported to be able to disconnect their machines from the batteries and run them just off the electricity coursing through the wires. When a larger storm hit in 1921 telephone exchanges and railroad routing stations spontaneously caught fire from the discharging electricity. The way our national grid is designed now would make a similar sized CME catastrophic.

Power transformers are the gatekeepers of electricity from the grid into local communities. To protect them from lightning strikes they are earthed into the ground to allow a current to dissipate. However this safety feature becomes a vulnerability when, during a particularly strong geomagnetic storm, the earth’s surface itself can begin to build up a charge. Swamped with currents far higher than they can handle they are liable to catch fire or melt. When key nodes in the grid are broken it puts undue stress on the others and could lead to a blackout of the entire system. By some estimates if we were hit by a CME as strong as 1859 it could take 4 to 10 years to replace all the damaged transformers, during which time many millions of people would not have ready access to electricity.

Now the world relies so heavily on electricity, the effects would be catastrophic. John Kappenman, an engineer and geomagnetic storm expert says "If you lose electricity, within a matter of days you essentially lose almost everything else." We wouldn’t be able to use phones, the internet, computers, we wouldn’t be able to refrigerate food, perform most healthcare or have light or warmth at night. When you combine the telecommunications blackout with bursts of electromagnetic radiation disrupting radio transmission, it could be a catalyst for utter chaos.

There are ways to defend against the effects on our electrical grid, by wiring up arrays of resistors and capacitors to the grounding cable the energy can be absorbed. With enough warning grids can be turned down or off to protect against overly high currents. As these costs are entirely voluntary however, most companies are unwilling to go to such effort, and governments are even less inclined to force anyone to prepare.

Even our ability to detect CME’s and get a brief 20 to 50 minute warning is at risk. There are three satellites dedicated to watching out for CME’s. Two satellites look at the Sun and can detect how big a CME is and whether it is heading towards us, but neither can tell how powerful the shockwave might be. That is performed by the ACE satellite, which measures the shockwave as it passes over it and can warn earth if the effects are going to be severe. All these satellites are beyond their nominal lifetimes and there are no concrete plans to replace them.

So maybe you feel a little luckier today for having not witnessed the collapse of modern society, but unless we start taking action soon we might not stay lucky for much longer.

Photo by Flickr user thebadastronomer