On September 1, 1859, amateur astronomer Richard Carrington made a discovery that would forever change the world. When the 33-year-old pointed his brass telescope towards the sky, he noticed a bright light suddenly appear above a grouping of large sunspots. At first, he thought it was a malfunction of his equipment, but he would soon realize he was watching an event blasting from the Sun itself. 

We now know that what Carrington observed was the largest geomagnetic storm on record to hit Earth. In the days that followed, the “Carrington Event” spewed electrified gas and subatomic particles amounting to the energy of 10 billion atomic bombs towards the planet, causing telegraph communications to fail, literally shocking operators, and causing systems to catch fire. Northern Lights were reported as far south as Cuba and Hawaii, allowing witnesses to read newspapers by the light of the auroras alone. 

Bear in mind, this all occurred in the same year that the first successful gasoline engine was demonstrated. In an era where modern technology rules our every move, a similar solar event would have detrimental effects that would impact nearly every aspect of life, from your ability to post a selfie to how your toilet flushes. But to understand how such an event would impact our world today, we first need to grasp how space weather works.  

The Three Stages Of A Solar Storm

The Sun’s power comes from nuclear fusion, turning hydrogen into helium and liberating energy in the form of light and heat. The hydrogen is in a charged plasma form, and as it moves it creates powerful currents and magnetic fields.

During the first stage of a solar storm, this magnetic energy can be released in spectacular fashion and is accompanied by X-ray and ultraviolet (UV) emissions. These are called solar flares. If these events are associated with the release of high-energy particles, they can become fully fledged solar storms or coronal mass ejections (CMEs), which we can think of as Sun “burps” (if the Sun belched with the power of 20 million nuclear bombs). During a CME, heated gas bubbles called plasma eject from the Sun, sending shockwaves rippling through the Solar System. Astronomers don’t know exactly why these occur but agree that the Sun’s magnetic field has something to do with it. The Sun is not a solid but made of plasma, a fluid-like state of matter that's electrically charged. This state is subjected to turbulence, and turbulence moves the Sun's magnetic field lines in much the same way as when we stretch a rubber band. Stretch it too much, though, and it will snap.

Altogether, the three combine to create the perfect solar storm.

Solar storms happen often, though it’s rarer that they project towards Earth. Storms much smaller than the ones responsible for the Carrington Event have wreaked havoc on our electrical systems and infrastructure, and a large one could take an even bigger toll. According to a 2009 NASA-funded study, almost nothing is immune from space weather and it impacts almost every aspect of modern society. In the US alone, damages would likely be $1-2 trillion in the first year, with a full recovery taking up to a decade or so, according to a 2008 report from the National Research Council. Other estimates are similar. 

Potential Impacts To Earth’s Climate

The Sun produces energy in many wavelengths, peaking in the visible but extending far into the infrared and ultraviolet. UV light is particularly important when it comes to the effects of space weather, as the amount we get from the Sun varies in an 11-year cycle. We entered a new cycle, Cycle 25 in December 2019, meaning we've passed the solar minimum and are heading towards a more active maximum in the next few years. When the Sun is more active, we get more UV light, which can impact the chemical composition of the stratosphere and change the temperature of the atmosphere. NOAA’s Space Weather Prediction Center (SWPC) reports that little is known about the role of UV light in Earth’s changing climate, but a theory holds that throughout the Sun’s cycle, cosmic rays may create nucleation in the atmosphere. This could potentially seed cloud formation, creating cloudier conditions and further affecting how much light reaches Earth. 

But hey, it’s not all bad. The aurora borealis (Northern Lights) and aurora australis (Southern Lights) are the result of electrons colliding in the Earth’s upper atmosphere between 80 and 500 kilometers (50-310 miles) above its surface, so at least we’ll have a killer view.

The Electrical Power Grid

In 1859, the world was not nearly as interconnected or dependent on power systems as it is today. Electricity is found in man-made systems but also occurs in the natural world. The Earth, its oceans, and atmosphere respond to the planet’s rotation, as well as the gravitational pull of the Moon and the variation of radiation from the Sun. Geomagnetic storms can cause disturbances to these systems, which were first observed in 1940, and have since been found to trigger power blackouts, trip up equipment, cause transformer losses, and interfere with long-line communication cables.

"Electric power is modern society's cornerstone technology on which virtually all other infrastructures and services depend," reads NASA’s report, continuing that more than 130 million people would be left without power and with “water distribution affected within several hours; perishable foods and medications lost in 12 to 24 hours; loss of heating [and] air condition, sewage disposal, phone service, fuel re-supply, and so on.”

A similar event occurred in March 1989, when a geomagnetic storm caused the collapse of Canada’s Hydro-Quebec power grid, leaving millions without electricity for as long as nine hours, with around 200 anomalies to the power grid felt from the Northeastern US to the Mid-Atlantic, spanning east into the Midwest. In 2017, a large sunspot produced a CME that became the largest solar flare of the decade, blacking out shortwave radios across Europe, Africa, and the Atlantic Ocean.

Global Positioning Systems

Nearly every cell phone, automobile, and any piece of equipment that requires any level of precise location measurement – from farming and construction to exploration and surveying – employs a global positioning system (GPS). The influence of this system is expected to be felt at a greater capacity in the coming years, with the industry expected to be worth nearly $3 billion in the next five years. 

GPS radio signals travel from the satellite to receivers on the ground, passing through the ionosphere when there isn’t space weather to disrupt it. Our GPS systems are fairly accurate, within a meter or so, but when the ionosphere is disturbed by space weather events, the models they operate on are no longer accurate. This could affect the accuracy of devices to within tens of meters or more.

High-Frequency Radio Communications

Ionospheric changes can also impact our radio transmissions, which are used in everything from car stereos to commercial airlines and federal communications. During a radiation storm, solar flares can disrupt radio communications in similar ways to failed satellite communications, however these tend to return to normal soon after. 

Satellite Systems

Satellite communications rule our every day and exist in the form of any entity that communicates with an artificial satellite in space – of which, around 2,000 are currently in use. Satellite communications use high-frequency signals similar to radio signals that can be affected when environmental conditions obstruct the pathway between two points (i.e. a cell phone tower and an orbiting satellite). When plasma is in the ionosphere, signals are also affected and there can be a total loss of communications.

This happened in 2003 during a series of solar flares and CMEs lasting nearly three weeks. Known as the Halloween Storms, they were particularly scary as they caused power outages across Sweden and damaged satellites as well as temporarily shutting down instruments in spacecraft.

"The effects of these storms were ghoulish enough that [aircraft controllers] had to re-route aircraft, it affected satellite systems and communications, and it also caused a power outage in Sweden for about an hour," said NASA solar scientist Holly Gilbert in a statement. 

How Do We Prepare?

Indications in 2012 suggested there is a one-in-eight chance we could see a catastrophic megastorm by 2020, but there really is no way to predict when or how powerful it might be. To be on the safe side, NASA calls for an infrastructure redesign that would enable power companies to take transformers offline before a storm hits. The space agency says that better forecasting measures would allow researchers to better predict when and where these solar flares appear and, if they’re headed towards Earth, give operators time to make adjustments.

Thanks to telescopes like the GREGOR telescope in Europe, the Inouye Solar Telescope, and the High-Resolution Coronal Imager, and missions like NASA's Parker Solar Probe and ESA's Solar Orbiter, the last couple of years have yielded the highest resolution images of the Sun ever produced, enabling us to learn more about our star, and hone our forecasting skills.

If all else fails, just look to the sky for a pretty show.