Over the last few decades, western civilisations have busily sown the seeds of their own destruction. Our modern way of life, with its reliance on technology, has unwittingly exposed us to an extraordinary danger: plasma balls spewed from the surface of the sun could wipe out our power grids, with catastrophic consequences.
The projections of just how catastrophic make chilling reading. “We’re moving closer and closer to the edge of a possible disaster,” says Daniel Baker, a space weather expert based at the University of Colorado in Boulder, and chair of the NAS committee responsible for the report.
It is hard to conceive of the sun wiping out a large amount of our hard-earned progress. Nevertheless, it is possible. The surface of the sun is a roiling mass of plasma – charged high-energy particles – some of which escape the surface and travel through space as the solar wind. From time to time, that wind carries a billion-tonne glob of plasma, a fireball known as a coronal mass ejection (see “When hell comes to Earth”). If one should hit the Earth’s magnetic shield, the result could be truly devastating.
The incursion of the plasma into our atmosphere causes rapid changes in the configuration of Earth’s magnetic field which, in turn, induce currents in the long wires of the power grids. The grids were not built to handle this sort of direct current electricity. The greatest danger is at the step-up and step-down transformers used to convert power from its transport voltage to domestically useful voltage. The increased DC current creates strong magnetic fields that saturate a transformer’s magnetic core. The result is runaway current in the transformer’s copper wiring, which rapidly heats up and melts. This is exactly what happened in the Canadian province of Quebec in March 1989, and six million people spent 9 hours without electricity. But things could get much, much worse than that.
Check out the article to see how much worse it can get, and what can be done to protect us:
The good news is that, given enough warning, the utility companies can take precautions, such as adjusting voltages and loads, and restricting transfers of energy so that sudden spikes in current don’t cause cascade failures. There is still more bad news, however. Our early warning system is becoming more unreliable by the day.
By far the most important indicator of incoming space weather is NASA’s Advanced Composition Explorer (ACE). The probe, launched in 1997, has a solar orbit that keeps it directly between the sun and Earth. Its uninterrupted view of the sun means it gives us continuous reports on the direction and velocity of the solar wind and other streams of charged particles that flow past its sensors. ACE can provide between 15 and 45 minutes’ warning of any incoming geomagnetic storms. The power companies need about 15 minutes to prepare their systems for a critical event, so that would seem passable.
However, observations of the sun and magnetometer readings during the Carrington event shows that the coronal mass ejection was travelling so fast it took less than 15 minutes to get from where ACE is positioned to Earth. “It arrived faster than we can do anything,” Hapgood says.
There is another problem. ACE is 11 years old, and operating well beyond its planned lifespan. The onboard detectors are not as sensitive as they used to be, and there is no telling when they will finally give up the ghost. Furthermore, its sensors become saturated in the event of a really powerful solar flare. “It was built to look at average conditions rather than extremes,” Baker says.