Occasionally, when the events are powerful enough, damaging radiation scatters through the atmosphere and strikes the surface of the Earth. These events are known as “ground level enhancements” of cosmic rays, one of the scientific euphemisms that pepper the literature on this topic. Since 1950 more than seventy ground level enhancements have happened, based on an international network of radiation monitors on Earth, akin to solar Geiger counters. A dominant concern is how these events affect airplane passengers and crews—particularly pregnant ones—as well as the equipment needed to fly the aircraft.
But in addition to how solar storms affect avionics and living tissue is the way they can damage hard-to-replace electrical infrastructure, pipelines, and other industrial technologies, particularly when their systems are interconnected. Those interdependencies are growing day by day, as societies link electrical systems ever more tightly together, unaware of the risks.
Two relatively recent solar storms have been minutely examined for their lessons on how vulnerable modern technological systems are to solar radiation. The first, on March 13 and 14, 1989, knocked out power in Quebec when storm-induced currents overwhelmed one part of the system and its built-in protective mechanisms kicked in, shutting down first one section of the grid and then every other in succession. Six million people were without power for nine hours. A nuclear unit transformer in Salem, New Jersey, overheated and had to be taken out of service temporarily. In the UK, the same storm damaged two electrical grid transformers. Scientists call it the day the sun made things dark.
A broader event, called the Halloween magnetic storm of 2003, happened after seventeen flares erupted in neighboring areas of the sun, many of which were followed by storms of radiation. A large one exploded on October 28, quickly followed by a coronal mass ejection. That mass of plasma was clocked at 2,000 kilometers a second by a nearby instrument, which functioned until protons from the flare blinded it. The next day, another huge flare burst forth, followed by yet another wild coronal mass ejection. Once their energy hit the Earth on Halloween, October 31, electrical engineers across North America raced to protect the electrical grid by shutting down key parts of it. Transformers in South Africa were badly damaged, and one in Malmö, Sweden, shut down, leaving fifty thousand people without light for an hour. At least thirteen nuclear power reactors took measures to protect their equipment from damage.
The event spawned the first-ever radiation alert to aircraft from the Federal Aviation Administration. Spikes of radiation entered the Earth’s atmosphere at the poles, where the magnetic field lines exit and enter. Flights over polar routes were redirected because passengers and pilots were at risk. Also, airlines could not rely on a key global positioning system for precision landing because satellites orbiting the Earth had shut down. Geomagnetic measurements for oil and gas drilling failed. Magnetic and geophysical surveys ceased to function. The US military had to cancel a mission at sea because the satellites that governed their communications were disabled. The $640-million Japanese scientific satellite ADEOS II was lost to space, carrying a NASA instrument worth $154 million. Astronauts at the International Space Station four hundred kilometers above the Earth (inside the Van Allen belts) had to duck for cover and hope for the best under layers of extra anti-radiation shielding that the Russians had thoughtfully provided. That action cut the radiation the astronauts experienced by about half.
The energy from the Halloween event pulsed through the galaxy for more than a year. The Mars Odyssey spacecraft was hit with so much radiation from the event’s solar energetic particles that its sensors shut down. The solar flare was so strong it outshone the stars, and the Mars spacecraft couldn’t navigate using them as reference points. Probes near Jupiter and Saturn recorded the event and so, much later, did the Voyager 2 spacecraft, 11 billion kilometers from the sun.
Far more serious—and therefore more telling because they are more akin to what the Earth will experience when the poles are reversing—are the biggest of the superstorms. They are far more intense pulses of energy tossed off from the sun that temporarily but severely weaken the Earth’s magnetic field. Scientists are aware of only two of this type of superstorm since they began chronicling the sun’s activity hundreds of years ago. The first is the Carrington event, named after Richard Carrington, the astonished British astronomer who watched it unfold. Baker has studied the event, which happened in 1859, the same year Boulder was founded and that Darwin published On the Origin of Species.
That was only twenty-eight years after Faraday had made his induction ring in the basement of the Royal Institution in London. Even when Faraday’s experiment was successful in producing electricity from a magnet, the idea of harnessing that electricity to power society was inconceivable. But by 1859, the first transatlantic electric cable had begun transmitting telegraph signals from Europe to North America. More than 100,000 miles of telegraph lines connected stations across those two continents and in Australia. It was the first continental-scale electric technology humans had created.
The event started with sunspots on the face of the sun on August 28. On September 1, Carrington saw “a singular outbreak of light which lasted about 5 minutes.” It was the first solar flare reported by a human. Carrington even drew pictures of it, small wormlike figures. The flare was followed by what we now know was a powerful coronal mass ejection—a blast of electrically conductive, magnetized plasma—and then by a storm of solar energetic particles. Slower than the electromagnetic waves of light that marked the solar flare, the plasma took seventeen hours and forty minutes to reach the Earth. We have learned, based on ice-core analysis, that it was the most dangerous solar radiation event of the previous five hundred years. It is considered the benchmark for worst-case, life-threatening exposure to solar radiation for astronauts. Not only was the storm savagely strong, but its magnetic field also ran opposite to the Earth’s. This was the recipe for an acute magnetic storm on Earth.
Stupendous auroras lit up the skies during the dawns of August 29 and September 1 and 2. Rather than in the usual narrow oval bands around the two poles, dramatic auroral displays could be seen in countries just a few degrees from the equator in both the northern and southern hemispheres, as well as in other parts of the world where they were unfamiliar. “The light appeared in streams, sometimes of a pure milky whiteness and sometimes of a light crimson. . . . The crown above, indeed, seemed like a throne of silver, purple and crimson, hung or spread out with curtains of dazzling beauty,” wrote a Washington reporter. “The whole sky appeared mottled red, the arrows of fire shooting up from the north like a terrible bombardment,” wrote a correspondent from Ohio. People were terrified. They believed their towns were on fire, and some raced to houses of worship to pray for the prevention of whatever horrors the lights foretold.
The new telegraph system, with its electrical lines, became a target for rampaging currents produced by the magnetic disturbance. Lines went down in New York, Boston, Philadelphia, Washington, Massachusetts, London, Brussels, Berlin, Mumbai, throughout Australia, and in every single telegraph office in France. In Pittsburgh, batteries connected to the telegraph wires emitted streams of fire. In Sweden, they sprayed electric sparks. In Norway, they sparked so much that they set papers on fire and the lines had to be attached to the ground to prevent the machines from being irrevocably damaged. In several places, including between Boston and Portland, the electrical currents swooping through the lines from magnetic variations were so great that telegraph operators could work off what they called the “celestial power” alone, after having disengaged the batteries.
• • •
The disturbance in the Earth’s magnetic field lasted for eleven days.
Not only had the outburst on the surface of the sun penetrated deep into the Earth’s atmosphere, it had also coursed through whatever electrical structures humans had made on its surface, rendering them useless. In today’s terms, the pulses of electric currents flowing
in the magnetosphere and the ionosphere cradled within it (the thick band of atmosphere 75 to 1,000 kilometers above the surface where cosmic and solar rays tear apart atoms, making ions) had produced oscillating magnetic fields at the Earth’s surface. By Maxwell’s laws, those magnetic fields had caused electrical currents to flow. Their conduits were the Earth’s crust and upper mantle. These are known as geomagnetically induced currents, or telluric currents, after the Latin word tellus for “earth.” The currents were looking for long, easy paths to flow in, driven by the oscillations in the magnetic field. The best ones they found were the grounded, highly conductive lines that humans had set up to move telegraph signals. But the power the currents carried was far too strong for the lines to handle. They were overwhelmed; they overheated and shut down, or sparked. Once the coronal mass ejection ran its course and the changing magnetic fields at the surface of the Earth stabilized, the telluric currents stopped.
Contemporary scientists had already noticed that telegraph lines became disturbed when the auroras were dancing. And a few years earlier, in 1852, Sir Edward Sabine, the architect of the magnetic crusade who obsessively plowed through voluminous global readings from the Magnetic Union of Göttingen to discern patterns, had linked sunspot activity with geomagnetic irregularities on the Earth. That was a surprise, and the first hint that the sun and the Earth’s magnetic field might frolic with each other. In fact, Carrington was watching the sun for dark spots on its surface in late August 1859 when he noticed the flare that preceded the superstorm. Nevertheless, many scientists of the day did not believe that the sun’s activity could have any effect on terrestrial systems. Even after the Carrington event, many remained unconvinced. Among the champions of the skeptics was Lord Kelvin, who had also stood staunchly behind another incorrect idea: the hard-boiled-egg theory of the Earth’s interior.
By the time the second huge superstorm struck, 153 years later, scientists harbored no doubt that the sun was causing the Earth’s magnetic field to react. They had been nervously waiting to see when the sun would produce what is now known as a Carrington-class superstorm, and wondering how it would affect the Earth when it hit. It arrived without warning on July 23, 2012, when the sun’s magnetic field was in a period of relative calm and no extreme events were expected. The reason why few people have heard of it is that by a quirk of fate, this violent eruption happened on the side of the sun facing away from the Earth. Had it occurred a week earlier, its full force would have been focused on this planet, its inhabitants, and our infrastructure.
Baker has conducted what amounts to a forensic analysis of what happened. The STEREO-A (Solar TErrestrial RElations Observatory) spacecraft, positioned in interplanetary space, captured the whole affair, and so did a few other craft nearby. Because they were outside the Earth’s magnetosphere, where the interplanetary magnetic field is relatively weak, the blast did not produce currents damaging enough to scotch the spacecraft’s equipment, and its instruments recorded information about plasmic speeds throughout the event.
It was far worse than anyone could have imagined and far worse than the Quebec or Halloween event. Again, it began with a solar flare, followed by a coronal mass ejection of unusual speed and strength thrusting a targeted mass of magnetized plasma in fast, swooping clouds out into space. The propulsion of solar energetic particles was among the strongest ever observed. A separate study found that the sun had likely produced a coronal mass ejection in the same region slightly earlier and that its trajectory had plowed a furrow through space, allowing the second one to move at more devastating speeds.
It was at least as strong as the Carrington event. Had it struck the Earth on a day when our planet was in position for the equinox, it would have been about half again as strong as the Carrington event, Baker calculated. Again, no one foresaw this event. The effects on the Earth’s electrical infrastructure would have been catastrophic, sending civilization back to a pre-electricity Victorian era, NASA said. People would not have been able to use anything that plugs into the sockets in a wall, for starters. But neither would they have been able to fill cars with gas, use banks, or even flush the toilet, because all those functions, including municipal septic systems, ultimately depend on electricity. The effects would have cascaded through society and the economy, even eventually causing long pipelines to corrode by overwhelming the circuitry that prevents their corrosion. It could have taken years to recover, according to reports analyzing the potential fallout from a superstorm.
Disturbing in its own right, the near miss of 2012 galvanized interest from the US and other governments to predict superstorms in better ways. Geomagnetic disturbances like the near miss have been named a focus of the international electric infrastructure security council, which was set up in 2010 to guard against “black sky hazards.” Scientists in the United States have begun making maps setting out risks to the electrical grid from geomagnetic storms. And in October 2015, US president Barack Obama established a detailed national space weather action plan to gather and disseminate more information about the phenomenon.
These analyses of what happened and what would have happened are based on a rare superstorm hitting while the Earth’s magnetic field is still strong. But the field has been weakening since before the Carrington event, and is far weaker now than in 1859. What if the poles were reversing and the field was down to one-tenth of its usual strength? Put aside for the moment the risks of rare Carrington-class superstorms. How would normal solar flares, which can happen multiple times a week, affect the Earth? What about the frequent, hard-to-predict coronal mass ejections? Episodes of potentially deadly solar energetic particles? The constant attack of galactic cosmic rays? These are routine occurrences that our magnetic shield protects us from. When the shield is down, what will they do to living creatures? The answers are not pleasant.
CHAPTER 27
lethal patches
Long before geophysicists suspected that a flip of the magnetic poles might be in progress, they began delving into a concept that startled them. It was the early 1960s. The theory of reversals was just beginning to creep into respectability. Its implications were breathtaking. Among them: Did reversals kill off or mutate species and therefore affect patterns of evolution? This suggestion went far beyond the idea that the magnetic field provides a refuge from cosmic radiation and shelters our atmosphere from solar winds that would rip it away. It was metaphysical: Did the inner machinations of the molten core help determine what lives and dies on the crust?
The first salvo, in 1963, stemmed directly from the discovery of the Van Allen belts. What would happen to all that radiation trapped in the belts when the poles reversed? Would solar wind be able to bathe the Earth in radiation, causing rampant genetic mutations? And had it done so during previous pole flips? The author of the page-and-a-half paper, Robert Uffen of the University of Western Ontario, hypothesized: yes.
“It is becoming increasingly apparent that the Earth is a heat engine the internal workings of which have controlled not only geological phenomena such as mountain building, volcanoes, and earthquakes, but also geochemical phenomena such as the development of the atmosphere and the oceans; geophysical phenomena such as the magnetic field and radiation belts; and even biological phenomena like the origin and evolution of life,” Uffen concluded.
The next step was to examine the rock record. This time, it wasn’t only to look for the magnetic memory locked in rocks, but also at its archive of fossils. It was obvious that reversals did not kill off all life, because life had persisted continuously on the planet for at least 3.6 billion years. But had previous reversals led to mass die-offs? At a first pass, there was little evidence. For one thing, the Earth had experienced just five mass extinctions. But there had been hundreds of reversals and near-reversals. Therefore, reversals didn’t cause mass extinctions, or at least not always. The logic of that line of reasoning broke down under scrutiny, though. Reversals last for perhaps a few thousand years—or
less—and the paleontological record is rarely precise to that time scale. It’s hard even to find a global rock record for such a short period, much less a record of species gone missing forever within it. We have evidence of the five mass extinctions because they spanned millions of years.
As researchers dug further into the data, some peculiarities began to spring up. Two of the mass extinctions coincided with abrupt changes in the tempo of reversals. The first was the one 252 million years ago at the end of the Permian period. It is known as the Great Dying because 95 percent of species on the planet vanished. The second was the one that killed off the dinosaurs and many other species 65 million years ago at the end of the Cretaceous period. A superchron, when the Earth’s magnetic field did not change for tens of millions of years, came before each. By contrast, during those two mass extinctions, the field reversed many times. One theory was that during the superchrons, species evolved without the need to adjust to the rigors of reversals, and so when reversals came, so did pulses of extinction. That may offer a bit of comfort about the vulnerability of species to a reversal today. Ever since the dinosaurs vanished, we have been in a relatively fast-paced pulse of reversals, which may have built some level of protection into the genetic code of species now on Earth.
By 1971, the scientific exploration had turned to comparing an index of the change in the number of taxonomic animal families over the past 600 million years—a measure of rates of extinction but not mass extinction—against the timing of reversals. There was an astonishingly high correlation, the author, Ian Crain of the Australian National University in Canberra, found. But why? Did reversals foster extinction and, therefore, the emergence of new species to replace them? Pointing to lab experiments, Crain proposed that the low magnetic field itself was the killer, causing difficulty in movement and reproduction.
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