May 117 min read

Could a Major Solar Storm Cause Chaos?

What’s the most destructive weather you can think of? Chances are that solar storms aren’t what you picture. But perhaps they should be.

The Sun doesn’t just send heat and light our way. It also belches out a colourful variety of destructive forces, including solar winds and phenomena known as coronal mass ejections (CMEs) – giant coiling magnetic fields carrying a dense plasma of energetic particles tens of thousands of kilometres wide.

Thanks to Earth's magnetic field, our planet is pretty well-protected. However, this defensive shield can occasionally become overwhelmed, causing geomagnetic storms like the one last night which led to rare and incredible displays of the Northern Lights all over Europe. It can also spell trouble…

Watch my short explainer to find out more:

Our biggest natural disaster risk?

In 2019, the U.S. Federal Emergency Management Agency (FEMA) warned that only two natural hazards would be capable of wreaking havoc on the entire country: a pandemic and a severe solar storm.

We all know what happened next. A few months later we were in the midst of the biggest pandemic in a century.

Today, no one needs to be convinced of the risk posed by the outbreak of new infectious diseases. But how likely are we to experience the other natural hazard FEMA warned of? And just how disruptive could a major solar storm be?

The answer starts with some strange goings-on around 165 years ago.

The Carrington Event

Early on Friday, 2nd September 1859, gold miners camping out in the U.S. Rocky Mountains woke up ready for another day’s work and started making coffee, bacon and eggs. They could hear birds singing and it seemed to be getting light. However, something unusual was happening. The sky was filled with extraordinarily bright and vivid colours, unlike any sunrise they had ever seen. Eventually, word spread that this morning light wasn’t the Sun. It was only 1am.

These spectacular auroras were visible to people all over the world. According to National Geographic, “northern lights were reported as far south as Cuba and Honolulu, while southern lights were seen as far north as Santiago, Chile.” At around the same time, telegraph stations – which had been springing up everywhere the past couple of decades – stopped working. Sparks flew from the machines and several lines caught fire. Telegraph operators struggled to keep communication services operating. Bizarrely, one U.S. line – between Portland and Boston – could still transmit messages even after operators disconnected the battery.

Compasses started playing up too, causing ships to become lost at sea. Elsewhere, there were reports of people getting electric shocks from doorknobs and other metal objects.

It sounds like the set-up for a blockbuster sci-fi thriller. However, unlike an M. Night Shyamalan film, the strange events of September 1859 did not remain a mystery for long.

Hours earlier, British amateur astronomer Richard Carrington had been working in his observatory in Surrey charting sunspots – large areas of the Sun’s surface darkened by its magnetic field – when he saw something he hadn’t witnessed before. “Two patches of intensely bright and white light broke out,” he wrote.

Carrington had captured the first recorded sighting of a solar flare, a rapid and intense variation in the Sun’s brightness that occurs when a build-up of magnetic energy in the solar atmosphere is suddenly released. Another amateur astronomer, Richard Hodgson, had observed the phenomena too.

Carrington quickly drew the link between this sighting and the massive geomagnetic storm that followed. The storm – now known as the Carrington Event – spurred the study of space weather.

The space weather report

Carrington’s observations and the strange events of 1859 led to an important realisation. While most weather here on Earth is caused by the heat and light reaching us from the Sun, we can also be affected by other things that this giant nuclear fusion reactor in the sky sends our way.

We’ve known for a long time that the Sun moves through an 11-year cycle, from a relatively quiet “solar minimum” to a very active “solar maximum.”

It’s during this active peak that the Sun is most likely to expel CMEs. Their intensity is usually gauged by their speed. While CMEs will typically take a few days to travel towards our planet, the one associated with the Carrington Event is believed to have made the 93-million-mile journey in just under 18 hours (meaning that it was travelling at over 5 million miles per hour).

The Sun’s current cycle has been more active than expected and is due to reach solar maximum in the next few months.

A worldwide shutdown?

In 1989, two solar storms much smaller than the Carrington Event plunged millions of Canadians into a nine-hour blackout, closed the Toronto Stock Exchange, significantly disrupted the U.S. power grid, and took radio stations offline.

These magnetic storms were the largest of the 20th century, and while the fallout was relatively contained and temporary, they served as a wake-up call; the consequences next time could be much worse.

With the internet now so central to our way of life, we have become far more vulnerable to the potential impacts of space weather than we were centuries or even decades ago.

“Geomagnetic storms attack the lifeblood of modern technology: electricity. A space weather storm typically lasts for two or three days, during which the entire planet is subjected to powerful electromagnetic forces,” writes Roger Dube, a research professor at the Rochester Institute of Technology.

A solar storm on the scale of the Carrington Event would damage and shut down power grids and communication networks worldwide. And, Dube warns, the aftermath could be devastating:

"After the storm passed, there would be no simple way to restore power. Manufacturing plants that build replacements for burned-out lines or power transformers would have no electricity themselves. Trucks needed to deliver raw materials and finished equipment wouldn’t be able to fuel up, either: Gas pumps run on electricity. And what pumps were running would soon dry up, because electricity also runs the machinery that extracts oil from the ground and refines it into usable fuel.With transportation stalled, food wouldn’t get from farms to stores.

"Even systems that seem non-technological, like public water supplies, would shut down: Their pumps and purification systems need electricity. People in developed countries would find themselves with no running water, no sewage systems, no refrigerated food, and no way to get any food or other necessities transported from far away. People in places with more basic economies would also be without needed supplies from afar. It could take between four and 10 years to repair all the damage. In the meantime, people would need to grow their own food, find and carry and purify water, and cook meals over fires."

While this is a worst-case scenario, consequences even a fraction as severe make this a threat worth taking very seriously.

Weathering the next storm

With no way of preventing solar storms, the best we can do is to prepare for them. This means having contingency plans and backup systems in place for when the next solar flare or CME comes hurtling through space towards us. These contingencies can include rerouting flights and temporarily shutting down power grids.

The U.S. National Weather Service has even published advice encouraging people to build emergency kits and develop family communication plans in preparation.

Of course, to take timely action, we first need to be able to forecast when these storms will hit. And with some CMEs reaching speeds of 6.5 million miles per hour, every second counts.

After the 1989 geomagnetic storm, NASA and the European Space Agency jointly launched a satellite to start monitoring geomagnetic storms and solar flares. The Solar and Heliospheric Observatory (SOHO) has been in orbit since 1996. Originally planned as a two-year mission, it is still monitoring the Sun and reporting solar wind patterns almost 30 years later. NASA’s Advanced Composition Explorer (ACE) was launched in 1997 to provide real-time space weather data and warn of geomagnetic storms. It is still operational today, although NASA predicts that the mission will likely end this year when the orbiter finally runs out of propellant.

With these satellites now well past their intended retirement ages, you may be reassured to learn that reinforcements are on the way.

Next year (2025) should see the launch of Space Weather Follow On-Lagrange 1 – a new space weather satellite that will orbit the Sun to collect the most detailed data and measurements yet on solar wind, the magnetic field and CMEs. At around the same time, NASA’s Parker Solar Probe is due to reach the pinnacle of its mission to capture observations from the outer core of the Sun. The probe, which launched in 2018, will swoop within about 4 million miles of the Sun’s surface. It has already broken records for being the closest spacecraft to the Sun, and the fastest man-made object ever built (it has been clocked at 330,000 mph and is still accelerating).

Advances in AI are helping to produce more accurate forecasts around CMEs on a collision course with Earth. Our understanding of how Earth’s magnetosphere is improving, too. In a brilliant example of crowdsourced science in action, a group of A-Level students from London were able to shed new light on how our planet’s protective field responds to blasts from the Sun by studying the sounds it makes.

Insights like these are going to be crucial for future space missions. Outside the Earth’s protective magnetosphere, solar wind and storms can have the effect of a nuclear explosion, delivering lethal doses of radiation, from which astronauts have to be protected. The solar wind also strips the atmosphere from planets like Mars, meaning any plan to one day live on the Red Planet will have to include a way of protecting colonists from those powerful blasts.

As our reliance on technology increases and we continue to venture out into the solar system, our understanding of space weather will only become more important. It’s the best defence we have against the kind of perfect solar storm that, sooner or later, will be heading Earth’s way.