Science to Live By: EMP—An Existential Threat


© J. Dirk Nies, Ph.D.

When the sun rose into a clear sky on the morning of September 1, 1859, amateur British astronomer Richard Carrington could not have imagined that he soon would become the first person ever to see a solar flare.

The solar flare that Carrington saw through his telescope, and its accompanying “coronal mass ejection” (CME), created an intense electromagnetic pulse (EMP) when it struck the Earth’s upper atmosphere. The resultant geomagnetic storm and its aftermath is referred to today as the “Carrington Event.”

If a similar solar flare and CME were to strike Earth in 2019, the associated geomagnetic storm could bring our modern technological world to its knees in just minutes. More on that later. First, a little historical background.

Richard Carrington was born in 1826 in the town of Chelsea, now an area of West London. He was the son of a prosperous brewer and groomed for a life in the Church of England. But Carrington’s passion and aptitude lay in scientific pursuits. An ambitious, industrious, and self-sufficient young man, he left academia in his late twenties to set up his own personal astronomical observatory at Redhill in the county of Surrey. After conducting three years of meticulous observations of the night sky, he published to great acclaim A Catalogue of 3,735 Circumpolar Stars observed at Redhill in the years 1854, 1855, and 1856.

Not content with nocturnal work only, during daylight hours, Carrington often fixed his telescope upon the surface of the sun. From his careful observation of the rate at which sunspots traverse the face of the sun, he determined that the surface of the sun rotated faster at its equator than it did at higher latitudes. His findings helped astronomers come to understand that the sun’s surface could not be solid, but instead was fluid.

The sun is a writhing ball of hot ionized gas (plasma). Upwelling and swirling of its electrically conductive plasma generate powerful magnetic fields that envelop the entire surface of the sun. Localized whirlpools within the plasma cause the sun’s magnetic field to become severely distorted and even ‘rupture’ at specific locales on its surface. When this happens, explosions, equal in power to billions of atomic bombs, release highly energetic electromagnetic radiation and eject massive quantities of electrically charged particles into space.

The Earth is 93 million miles away from the sun. Given Earth’s relatively small size, it presents a minuscule target. Therefore, solar flares and CMEs emanating from the sun almost always miss the Earth, traveling harmlessly into deep space. But every once in a while, they don’t. And this is just what happened on that fateful September morning.

While Carrington was carefully sketching a cluster of large sunspots visible through his telescope, abruptly and unexpectedly, he saw “two patches of intensely bright and white light” burst forth from these sunspots. Within five minutes, these lights vanished as quickly as they had come. He had witnessed in real time a massive solar flare. And before the day was over, the world would feel its impact as a geomagnetic storm like none other in modern history.

The Carrington Event was not the result of the single blast from the surface of the sun Carrington had observed on September 1, but a one-two punch that had actually begun several days earlier.

On the night of August 28, for example, telegraph lines—which acted like large antennas stretched across North America—became inoperable as the first of the solar storms hit the Earth’s magnetosphere. In Pittsburgh, “streams of fire” poured out of telegraph circuits. In Washington, D.C., an “arc of fire” transversed from telegraph operator Frederick Royce’s forehead to a grounding wire.

During the day of September 2, after the second solar storm hit, employees in the Boston office of the American Telegraph Company discovered they could unplug the batteries that powered their telegraph machines and still transmit messages to Portland, Maine using only the current generated in the telegraph wires by the electrically charged atmosphere.

These twin solar storms caused nighttime displays of the Aurora borealis to be so bright that birds began to sing. People in Massachusetts could read their newspapers at midnight by its light. The northern lights were so vibrant and so extensive that they could be seen as far south as Cuba. In South Carolina, the Charleston Mercury ran the following account of their splendor as experienced from nearby Sullivan’s Island: “The eastern sky appeared of a blood red color. It seemed brightest exactly in the east, as though the full moon, or rather the sun, were about to rise. It extended almost to the zenith. The whole island was illuminated. The sea reflected the phenomenon, and no one could look at it without thinking of the passage in the Bible which says, ‘the sea was turned to blood.’ The shells on the beach, reflecting light, resembled coals of fire.”

More recently, a solar flare and CME of similar magnitude to the Carrington Event passed through Earth’s orbit on July 23, 2012. Fortunately, the Earth had orbited past that spot a week earlier. The National Academy of Sciences, NASA, and university scientists estimate that if the Earth had been in its direct path, the impact on our electrical power grid and the internet would have been catastrophic. Repair costs would have been in the trillions of dollars. Full restoration would have taken years to complete. We were very lucky, this time.

On a more sinister note, a nuclear attack conducted in outer space and designed to generate an EMP in the atmosphere could have even more devastating consequences.

In their non-classified July 2017 Executive Report to Congress, the “Commission to Assess the Threat to the United States from Electromagnetic Pulse (EMP) Attack” sees a “high-altitude nuclear explosion-generated electromagnetic pulse as an existential threat to the survival of the United States and its allies that can be exploited by major nuclear powers and small-scale nuclear weapons powers, including North Korea and non-state actors, such as nuclear-armed terrorists.” The Commission, convened by Congress under the National Defense Authorization Act for Fiscal Year 2016, further wrote “A nationwide blackout of the electric power grid and grid-dependent critical infrastructure—communications, transportation, sanitation, food and water supply—could plausibly last a year or longer. … An extended blackout today could result in the death of a large fraction of the American people through the effects of societal collapse, disease, and starvation. While national planning and preparation for such events could help mitigate the damage, few such actions are currently underway or even being contemplated.”

We’ve come a long way since the telegraph cables of Victorian times. Our highly sophisticated, complex, interconnected electrical system undergirds the global economy and supports the lives of billions of human beings. As things stand presently, most all of us could not survive for long without it. On a humorous yet sobering side note, a gas station in Crozet recently told our neighbor she could not pay cash to fill up her car because of a glitch in their electronic pumping system; they could take only a credit card.

Scientists and engineers designed the civilian electric power grid and the grid-dependent critical infrastructure with scant regard to their vulnerability to EMPs (generated by either the sun or nuclear weapons detonated above the atmosphere). I add my voice to those who feel there is too much a stake to remain ignorant or blasé about these vulnerabilities. The consequences are simply too dire.

I wish neither to play Russian Roulette with the sun, nor do I want our entire country to be taken down by rogue actors who detonate a relatively unsophisticated nuclear device several hundred miles above St. Louis. I wish for a more intelligent, resilient electrical system to be phased in that is hard to bring down when one or more parts are damaged. And more immediately, I support retrofitting key elements of the current system to harden them against a natural or artificial 21st Century Carrington Event.

Editor’s Note:  On March 26, President Trump signed an Executive Order titled “Co- ordinating National Resilience to Electromagnetic Pulses.”  For the first time since this threat became known decades ago, it establishes that “It is the policy of the United States to prepare for the effects of EMPs through targeted approaches that coordinate whole-of-government activities and encourage private-sector engagement. The Federal Government must provide warning of an impending EMP; protect against, respond to, and recover from the effects of an EMP through public and private engagement, planning, and investment; and prevent adversarial events through deterrence, defense, and nuclear nonproliferation efforts. To achieve these goals, the Federal Government shall engage in risk-informed planning, prioritize research and development (R&D) to address the needs of critical infrastructure stakeholders, and, for adversarial threats, consult Intelligence Community assessments.” 


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