It sounds like something from an overblown disaster film, or the opening scenes of some post-apocalyptic drama. A violent solar storm ejects a massive chunk of our sun’s corona and sends it on a collision course with Earth. As the coronal mass hits our magnetosphere, humanity’s electrically powered civilisations are unmade.
Shockwaves, as transformers at a nearby substation explode. Some appliances spark and catch fire, while electronic devices give a hiss and pop as induced currents fry their internal components.
This is a Carrington Event, and it is not some made-up cataclysm to serve as the premise for a new Netflix original series.
One of these events has happened within human memory, and another could happen at any moment. The only thing that saved us the first time was that we weren’t so wholly dependent on electricity and electronics.
It is true that a Carrington Event is a worst-case scenario and, compared to a typical human lifespan, it is a rare occurrence.
Frequency and likelihood should not be confused, though. Just because something doesn’t happen often does not mean that it will not eventually happen.
Coronal mass ejections that are smaller in scale than a full Carrington-class event can also be devastating.
A smaller solar storm caused the electrical grid in parts of Canada to go down in 1989. The Earth also narrowly avoided a Carrington-sized coronal mass ejection in 2012.
However, we will almost certainly get hit with one eventually. The only question is when, and how ready we will be.
Readiness, not fear-mongering
Heliospheric physicists in South Africa are among those working on the problem of predicting potentially damaging coronal mass ejections (CMEs).
The South African National Space Agency also hosts the only Space Weather Regional Warning Centre for Africa, which operates as part of the International Space Environment Service.
One of the top emerging researchers in the field is Ruhann Steyn, who, as part of his Master’s degree, derived new equations that describe the magnetic field of the sun.
Steyn is a physics lecturer and PhD student in the Centre for Space Research at North West University. His PhD focuses on the transport of very energetic particles from the sun to the Earth, specifically for space weather prediction.
Steyn says that although the physics of Carrington Events are well-understood, there is a big responsibility on the scientific community to educate people about Carrington Events without crying wolf or coming across as prophets of doom.
Scientists need to be up-front about the uncertainty surrounding Carrington Events and explain why it is important to be ready for one, even if they are rare.
“Although it could happen this afternoon or in 150 years, it is something people should know about and it is something that there should be a plan for,” Steyn said.
The Carrington Event is the name given to a major solar storm that happened in 1859. It gets its name from one of two amateur British astronomers, Richard C. Carrington and Richard Hodgson, who observed and recorded a “super flare” on the surface of the sun.
It was one of the largest geomagnetic storms on record and caused havoc in the early telegraph system.
Operators reported receiving electric shocks and being able to send and receive messages even after disconnecting the power from their telegraph machines. Sparks were also visible from telegraph pylons.
If such a CME were to hit Earth today, the effects would be devastating.
The Carrington Event occurred close to the solar maximum — a time during which the sun goes through a lot of sunspot activity.
Steyn explained that our sun has an eleven-year cycle. Currently, it is in a deep minimum, which effectively decreases the likelihood of the Earth being hit by a Carrington-class coronal mass ejection.
Over the next five or six years, activity on the sun will increase until it reaches solar maximum again, which is when large CMEs are more likely.
Aside from destroying the electrical grid and electronic devices by inducing currents that they are not designed to handle, a Carrington-class event will bring down the Internet and disrupt telecommunications networks.
While fibre optics are immune from the effects of such a geomagnetic storm, fibre networks still need electricity to operate. If the electric grid goes down, so does the Internet.
It also won’t be easy to restart the grid, as destroyed transformers would first have to be repaired or replaced. This could take months or years, depending on the extent of the damage.
The effect on satellites and aircraft is also a cause for concern.
Such a massive solar storm would knock out the electronics in the satellites orbiting the Earth, and it would also heat up the upper atmosphere. This would increase the density of the air, causing increased drag on low earth orbit satellites.
Many of these satellites would simply fall from the sky, as they would no longer be going fast enough to stay up.
Without avionics, many commercial airliners would crash.
Passengers will also face a burst harmful radiation from our sun, which will arrive long before the actual plasma from the CME does. Depending on the strength of the storm, the radiation could cause DNA damage and cancer.
Load-shedding — the benefits of South Africa’s rolling blackouts
Perversely, rotational load-shedding in South Africa may have helped better prepare the country for the threat of a large solar storm.
The reason Eskom implements rolling blackouts is to prevent South Africa’s electricity grid from collapsing completely, as a national blackout would be catastrophic.
However, Eskom’s supply problems have also resulted in it having to face the real question of what must be done in the event of a total blackout.
The answer is a “black start” — restarting South Africa’s power plants without any electricity in the grid to bootstrap the process.
Power plants use some of the electricity they generate to operate equipment such as conveyor belts that feed coal into furnaces, so to start them up you need to start with a small generator.
A typical scenario would be using a small diesel generator to start up a larger generator, which in turn is used to start parts of the power plant.
While having black start procedures in place will certainly benefit South Africa in the event of a Carrington-class solar storm, the larger issue would be getting hold of replacement parts.
If a global event damages electrical grids around the world, there will probably be a long waiting list to buy replacement transformers and other parts.
Being able to recover from a total outage of the electrical grid is only useful if you are able to protect your infrastructure from damage.
Not-so-early warning system
Currently, the most effective way to defend against a Carrington Event is to switch off anything electrical. Unfortunately, the major problem is ensuring that people are warned in time to act.
“It’s very storm-dependent,” Steyn said. “If the configuration is very simple it takes a lot less time to put it through a model, and you can have three days’ warning.”
If you are unlucky, it can take a very long time for computers to crunch the numbers and then you may only get an answer three hours before the CME hits.
This is the problem that researchers like Steyn are working on, but it is also only one aspect of the issue. There are also social and political barriers that must be overcome.
“You can imagine, if I pick up the phone and call Sweden to say that they need to switch off [their grid] because my model predicts that they are going to be hit, obviously they are going to say, ‘Who are you? We are going to run our own models,’” said Steyn.
“By the time they’ve run their own models, the storm would have already hit.”
Steyn said that because of this, there is a big push in the international community work together and consolidate space weather prediction.
“If one of our allies says, ‘Listen, you need to switch off,’ then we must be able to trust them, switch off, and see what happens.”