One hundred fifty-nine years ago, our sun belched out a sea of charged particles aimed at Earth. It sped toward us at millions of miles per hour, walloping the planet hard enough to addle the world's telegraph systems and bring the northern lights as far south as Jamaica.
Damage from the solar storm, called the Carrington Event, was pretty limited — chiefly because the world didn't have a lot of very long wires that are susceptible to disruption. But that was then, and a massive solar storm will come our way again.
That's because the sun is constantly convulsing with titanic forces, sending megatons of feisty charged particles across the 93 million miles to Earth. Although our planet is shielded by a vast, invisible magnetic field, those charged particles can punch through. When they do, they can cause widespread disruption in today's continent-spanning electrical system. But not just the world's electrical grid. A massive wave of charged particle emissions can also cripple orbiting communications satellites and force planes to detour around radiation-bathed polar regions.
"An event of that scale could be catastrophic if it happened tomorrow," says Francis O'Sullivan, director of research for the Massachusetts Institute of Technology's Energy Initiative. "It's not just the lights going off now. It's bank accounts disappearing.
"It's utterly central to everything, including national defense."
That's partly why both NASA and the European Space Agency have launched a handful of spacecraft to observe the sun's: expulsions of electrically charged particles called coronal mass ejections. Imagine an arc of material somewhat like a splash of water thrown from a bucket — only a CME can weigh a billion tons, easily dwarfs the Earth in size, and hurtles at speeds that can exceed a million miles an hour.
At its most active, the sun can belch out two or three CMEs a day.
That's worrisome, to say the least. But there's good news, too. Greater understanding of space weather along with improvements to the should help us withstand these solar onslaughts.
We have much better views of solar activity in recent years, thanks to data from NASA's twin Solar Terrestrial Relations Observatory (Stereo) spacecraft and other high-tech orbiting detectors. But there's still a lot of guesswork.
The Stereo spacecraft spot CMEs almost immediately but they can't figure out the magnetic field's orientation. This is an essential piece of information. If the giant cloud's magnetic field is aligned with the Earth's, the particle cloud "will bounce off the Earth's shield like a bumper car with little impact," says space plasma physicist Tamitha Skov.
But if the two magnetic fields point in opposite directions, the CME strips away the Earth's protection. "Space gets a lot closer to home," says Jesse Woodroffe, who studies space weather and its link to national security at Los Alamos National Laboratory in New Mexico.
Information about the field orientation only comes from the Advanced Composition Explorer (ACE), parked about 860,000 miles away from Earth.
"We have 30 minutes' notice whether it points north or south" — in other words, whether it's harmless or trouble, Woodroffe says.
That was then
On the morning of Sept. 1, 1859, British researcher Richard Carrington was making his usual observations of sunspots, peering at an 11-inch image of the sun optically projected onto a plate of glass. "Two patches of intensely bright and white light broke out," he wrote in a paper published the next year.
It was a solar flare, the burst of light that often accompanies a CME.
The massive solar storm reached Earth hours later. Tens of thousands of miles of telegraph lines were knocked out of commission for at least eight hours as electrical currents generated by the solar storm interfered with signals. Some operators managed to send telegrams by disconnecting the telegraph's battery and using storm-induced currents instead.
Frederick Royce, working in Washington, DC, found out the hard way what can happen when such currents flow through telegraph equipment.
"I received a very severe electric shock, which stunned me for an instant," The New York Times quoted him saying. "An old man who was sitting facing me, and but a few feet distant, said that he saw a spark of fire jump from my forehead" to the telegraph receiver.
There have been more solar troubles since then.
The 1921 "railway storm" caused fires at telegraph offices in New York City railway stations, Woodroffe says. A solar storm in 1989 knocked out power in Canada's Quebec province, and another in 2003 left millions of people in the dark for 12 hours in eight US states and Ontario.
A Carrington-class solar storm would be dramatically worse.
The basic problem stems from electrical currents that solar storms generate in the Earth's ionosphere. Those, in turn, induce currents in the power grid that can lead to two unfortunate outcomes. One is voltage collapse — a type of power blackout that can affect entire electric grids. The other is transformer failure.
Transformers change one voltage to another — increasing it for long-distance power transmission and decreasing it for household use. Solar storms could destroy power grid transformers, which can be as big as a house, cost more than $10 million and take 12 to 18 months to replace. It's one reason a science and engineering firm called Metatech warned in 2008 that a massive solar storm could cost the US economy between $1 trillion and $2 trillion and take four to 10 years to recover from.
That projection is too dire, though, say transformer experts at the Institute of Electrical and Electronics Engineers (IEEE) as well as Scott Backhaus, an expert in grid resiliency at LANL.
"Of the potential impacts, the one everybody is concerned about is a large power transformer overheating," says Backhaus. "What would probably happen before that would be voltage collapse."
While not as devastating, voltage collapse can still cause regional problems. And the more widespread the blackouts, the harder a recovery becomes because broader outages require power plants to initiate a "black start": using their own power sources, like diesel generators, for the electricity needed to restart the whole plant.
Solar storms cause other problems, too. Satellites beam navigation radio signals to everything from your phone and your car's sat-nav system to oil rigs and airplanes. Massive bursts of charged particles can hobble those services, as well as phone calls and internet data transfers.
Space weather also can expose aircraft to high levels of radiation. The Earth's magnetic field ordinarily provides protection except near the north and south magnetic poles, but CMEs push that radiation down toward the equator. That means transcontinental flights that usually travel over a pole must detour to less direct routes.
Facing the inevitable
We need to prepare.
Carrington-class events sweep the Earth about every 80 to 150 years, according to LANL's Woodroffe. "In July 2012, an incredibly large CME just missed us," he says.
We're adapting our electrical grid in North America — helped politically by the fact that those fixes also help ward off attacks involving high-altitude nuclear weapon explosions. A 2016 rule, for example, requires utilities to test transformers for vulnerabilities to big disturbances in the Earth's magnetic field and replace problematic hardware within four years.
Adoptinglike wind and solar also helps. As we rely less on massive central power plants and more on local power sources, the grid will become more resilient, MIT's O'Sullivan predicts.
The stakes couldn't be higher.
"If you think what would happen if the stock exchange was taken offline for a week or month or if communications were down for a week or a month, you very quickly get to a point where this might be one of the most important threats the nation faces, bar none," O'Sullivan says.
"It's not one we can negotiate a settlement around."
This story appears in the summer 2018 edition of CNET Magazine. Click here for more magazine stories.
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