Largest Solar Storm in Nearly a Decade

Today (Tuesday) the Earth was hit by one of the largest solar storms in a  nearly a decade. (Story here).

The largest solar storm in almost a decade swept across Earth on Tuesday, affecting air traffic across the North Pole and radio communications, in a harbinger of fiercer outbursts from the Sun predicted for the year ahead, federal experts said.

A solar eruption late Sunday launched a cosmic tsunami of energy, in the form of charged particles, radio static and X-rays, across the 93 million miles to Earth. It was the biggest burst of speeding particles since October 2003, according to the National Oceanic and Atmospheric Administration's Space Weather Prediction Center in Boulder, Colo.

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Delta Air Lines Inc. and United Continental Holdings Inc. said they were rerouting some transpolar flights to avoid the storm. Atlanta-based Delta said some flights to Detroit from Hong Kong, Shanghai and Seoul took a more southerly route on overnight flights, though a spokesman said planes flew faster to minimize delays. Tuesday departures from the U.S. were expected to follow similar routes. United, which operates a number of transpolar flights from Chicago and Newark airports, said it had rerouted flights between Washington and Dubai.

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At the height of severe solar storms in 2003, almost daily communications blackouts required that flights be rerouted. The Federal Aviation Administration for the first time also warned pilots on polar routes to stay at lower altitudes to avoid slightly higher radiation levels.

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In its normal, 11-year solar cycle of sunspots and flares, the Sun typically triggers thousands of such storms. This week's storm is among the more powerful, the space-weather experts said. Such storms are likely to become more frequent as the sun approaches its "solar maximum," predicted for May of next year.

"By this time next year, we expect to see a storm like this a couple more times," Mr. Biesecker said.

Of course, the real concern is something like the Carrington Event of 1859. On September 1, 1859, a massive solar flare rivaling the brightness of the Sun erupted.

Just before dawn the next day, skies all over planet Earth erupted in red, green, and purple auroras so brilliant that newspapers could be read as easily as in daylight. Indeed, stunning auroras pulsated even at near tropical latitudes over Cuba, the Bahamas, Jamaica, El Salvador, and Hawaii.

Even more disconcerting, telegraph systems worldwide went haywire. Spark discharges shocked telegraph operators and set the telegraph paper on fire. Even when telegraphers disconnected the batteries powering the lines, aurora-induced electric currents in the wires still allowed messages to be transmitted.

"What Carrington saw was a white-light solar flare—a magnetic explosion on the sun," explains David Hathaway, solar physics team lead at NASA's Marshall Space Flight Center in Huntsville, Alabama.

Coronal mass ejections on the scale of the Carrington Event appear to be rare. According to the article from NASA:

"In the 160-year record of geomagnetic storms, the Carrington event is the biggest." It's possible to delve back even farther in time by examining arctic ice. "Energetic particles leave a record in nitrates in ice cores," he explains. "Here again the Carrington event sticks out as the biggest in 500 years and nearly twice as big as the runner-up."

These statistics suggest that Carrington flares are once in a half-millennium events. The statistics are far from solid, however, and Hathaway cautions that we don't understand flares well enough to rule out a repeat in our lifetime.

And what then?

Lanzerotti points out that as electronic technologies have become more sophisticated and more embedded into everyday life, they have also become more vulnerable to solar activity. On Earth, power lines and long-distance telephone cables might be affected by auroral currents, as happened in 1989. Radar, cell phone communications, and GPS receivers could be disrupted by solar radio noise. Experts who have studied the question say there is little to be done to protect satellites from a Carrington-class flare. In fact, a recent paper estimates potential damage to the 900-plus satellites currently in orbit could cost between $30 billion and $70 billion. The best solution, they say: have a pipeline of comsats ready for launch.

This article from National Geographic goes into more detail on what would happen if another flare on the scale of the Carrington Event were to happen today:

In 1859, such reports were mostly curiosities. But if something similar happened today, the world's high-tech infrastructure could grind to a halt.

"What's at stake," the Space Weather Prediction Center's Bogdan said, "are the advanced technologies that underlie virtually every aspect of our lives."

Solar Flare Would Rupture Earth's "Cyber Cocoon"

To begin with, the University of Colorado's Baker said, electrical disturbances as strong as those that took down telegraph machines—"the Internet of the era"—would be far more disruptive. (See "The Sun—Living With a Stormy Star" in National Geographic magazine.)

Solar storms aimed at Earth come in three stages, not all of which occur in any given storm.

First, high-energy sunlight, mostly x-rays and ultraviolet light, ionizes Earth's upper atmosphere, interfering with radio communications. Next comes a radiation storm, potentially dangerous to unprotected astronauts.

Finally comes a coronal mass ejection, or CME, a slower moving cloud of charged particles that can take several days to reach Earth's atmosphere. When a CME hits, the solar particles can interact with Earth's magnetic field to produce powerful electromagnetic fluctuations. (Related: "Magnetic-Shield Cracks Found; Big Solar Storms Expected.")

"We live in a cyber cocoon enveloping the Earth," Baker said. "Imagine what the consequences might be."

Of particular concern are disruptions to global positioning systems (GPS), which have become ubiquitous in cell phones, airplanes, and automobiles, Baker said. A $13 billion business in 2003, the GPS industry is predicted to grow to nearly $1 trillion by 2017.

In addition, Baker said, satellite communications—also essential to many daily activities—would be at risk from solar storms.

"Every time you purchase a gallon of gas with your credit card, that's a satellite transaction," he said.

But the big fear is what might happen to the electrical grid, since power surges caused by solar particles could blow out giant transformers. Such transformers can take a long time to replace, especially if hundreds are destroyed at once, said Baker, who is a co-author of a National Research Council report on solar-storm risks.

The U.S. Air Force Research Laboratory's Cliver agrees: "They don't have a lot of these on the shelf," he said.

The eastern half of the U.S. is particularly vulnerable, because the power infrastructure is highly interconnected, so failures could easily cascade like chains of dominoes.

"Imagine large cities without power for a week, a month, or a year," Baker said. "The losses could be $1 to $2 trillion, and the effects could be felt for years."

This article from the Washington Post also delves into the possible impact:

Communications satellites will be knocked offline. Financial transactions, timed and transmitted via those satellite, will fail, causing millions or billions in losses. The GPS system will go wonky. Astronauts on the space station will huddle in a shielded module, as they have done three times in the past decade due to “space weather,” the scientific term for all of the sun’s freaky activity. Flights between North America and Asia, over the North Pole, will have to be rerouted, as they were in April during a weak solar storm at a cost to the airlines of $100,000 a flight. And oil pipelines, particularly in Alaska and Canada, will suffer corrosion as they, like power lines, conduct electricity from the solar storm.

But the biggest impact will be on the modern marvel known as the power grid. And experts warn that the grid is not ready. In 2008, the National Academy of Sciences stated that an 1859-level storm could knock out power in parts of the northeastern and northwestern United States for months, even years. Report co-author John Kappenmann estimated that about 135 million Americans would be forced to revert to a pre-electric lifestyle or relocate. Water systems would fail. Food would spoil. Thousands could die. The financial cost: Up to $2 trillion, one-seventh the annual U.S. gross domestic product.

"Thousands could die"? That is optimistic. Try, tens of millions could die. (See, e.g., this article discussing the impact of an EMP attack). While the risk of another Carrington Event is probably low--i.e., probably not within our lifetime--an EMP attack is more likely.