7
Fire in the Sky
The storm, when it struck, was a classic example of perhaps the oddest sort of foul weather the Earth is plagued with . . .
John Brooks, “The Subtle Storm”
On the night of February 10, 1958, the brightest lights in New York City were not on Broadway. Instead, they were dancing in the sky over Central Park and the Battery. Just days after a brutal winter storm dumped snow and freezing rain on much of the East Coast (as far south as the Gulf states) and kept temperatures hovering between 0 and 20 degrees Fahrenheit, auroral rays and arcs were visible through the smoke and city lights of Manhattan. One of the most intense auroral displays over the Americas in the twentieth century occurred that night. Nature was painting the town, the snow, and the sky red.
The intensity of the great aurora and magnetic storm of February 1958 was nearly as big a surprise to some scientists as it was to
the awed and startled public. Two days earlier, observers at the Sacramento Peak Solar Observatory in New Mexico detected a series of solar rumbles in the vicinity of sunspot region ABOO, a dark blotch that covered 3 billion square miles of the Sun’s face. “Like the milder rumblings before a thunderclap, seven smaller flares had been counted that day before the big one came,” journalist John Brooks wrote in an article for The New Yorker. The “big one” arrived at 2:08 p.m. Mountain Time on February 9, when a white-light flare burst into view. Four minutes after the onset of the big flare, the Harvard Radio Astronomy Station at Fort Davis, Texas, began hearing radio noise from the Sun. Brooks noted that during the greatest solar flares “the Sun sends out bursts of radio noise that, when picked up by special high-frequency receivers on Earth, sound like sausages being fried.” The flashing and popping on the Sun lasted for nearly two hours.
News of this “whopping big” flare, as the staff of Sacramento Peak called it in their initial reports, was transmitted to Walter Orr Roberts at the World Data Center on Solar Activity at the High Altitude Observatory in Boulder, Colorado. As one of the lead U.S. scientists for the International Geophysical Year (IGY),1 Roberts was charged with deciding whether or not to send an official advisory for a “special world interval.” Such alerts—part of an international science program to make coordinated studies of geophysical phenomena—were intended to provoke scientists to look out for anything out of the ordinary. Despite the exuberance of the messages from the solar observatories, few people in the laboratories and agencies charged with monitoring space weather expected the storm to have such impact. Radio communication experts predicted that conditions would remain “fair to good.” Noting that the flare was not necessarily the largest type (observations from other optical and radio observatories participating in the IGY did not agree with the “whopping big” classification from Sacramento Peak) and that “special world intervals” were a strain on limited science budgets, Roberts decided against rallying the troops. It was a decision that he would later openly regret. Within 28 hours, one of the biggest magnetic storms on record commenced.
The magnetic storm started around 8:30 p.m. Eastern Time on February 10, as magnetometer needles began to quiver at the World Warning Agency in Fredericksburg, Virginia, and in other stations around the world. Auroras sprang up in their usual northern regions but then began to descend toward the middle latitudes. “At one minute before nine, New York time, all magnetic hell broke loose from east to west and from Pole to Pole,” wrote Brooks. A full magnetic storm commenced—a storm that is still ranked in the top 12 of recorded history.
“If the human organs of balance and orientation depended upon magnetism rather than gravity,” wrote Walter Sullivan, the dean of modern science writers, in his book Assault on the Unknown, “every man in the world would have been dizzy, yet a large portion of this planet’s population sat or slept comfortably at home, unaware of what was going on.”
Those who were awake and attentive spied one of the most spectacular auroral light shows in U.S. history. From Canada to the Gulf of Mexico, rich red auroral lights (the calling card of the greatest magnetic storms) filled the heavens. That night the skies over almost all of North America were clear and the auroral displays were disproportionately concentrated over the continent. Reports of aurora sightings poured in from the usual places but also from Tulsa, Los Angeles, Havana, and Miami and from a steamship off the coast of Acapulco. The flickering, blood-red skies led to hundreds of false reports of fires. Sky watchers across the lower 48 states of America were treated to occasional turns of green and white auroras—typically visible only at high latitudes— and of auroral coronas—rays converging to a point, appearing like a shower of light. The New York Times noted that it was “one of the few occasions in which the aurora drapery had been seen here.”
But all was not so pretty and bright for those working in the electric power and communications industries. As the magnetic storm raged through the night, huge geomagnetically induced currents surged through the wires and cables. In Ontario, circuit breakers were tripped by the storm, plunging Toronto into a short-lived blackout. Lights flickered in Minnesota, the Dakotas,
Montana, and British Columbia. Telephone and Teletype circuits were disrupted between the United States and Europe for nearly three hours due to excessive currents on the coaxial cable links from Newfoundland to Scotland. Telegram messages on the Western Union cables were garbled, as stray electric currents flowed from west to east through the lines and potential drops varied by as much as 320 volts. Telephone calls from the United States to Europe were received in alternating sequences of whispers and squawks.
Radio communication was not much better. From 9 p.m. to 11 p.m. on the East Coast, radio operators for American Telephone and Telegraph, The New York Times, and RCA Communications struggled to sustain their transatlantic radio signals. They rerouted their messages through radio stations at lower and lower latitudes until eventually those signals faded as badly as the westeast signals. In Boston, television viewers noted that two of their shows mysteriously swapped channels. By 11 p.m., all radio contact between the United States and Europe faded into silence for two to three hours. As Brooks wrote: “The Old World and the New were in scarcely better touch than they had been in the days of the clipper ships.”
The radio blackout was particularly troublesome for the airline industry. More than 100 planes were “groping their way in one direction or the other” between Europe and North America during the magnetic storm. Under normal circumstances, they would have relied on radio transmissions to relay information on weather, traffic, and landing conditions. But on February 10, pilots found that they could only make radio contact if they were within a visible line of sight of a station. The cockpit airwaves were buzzing more than usual as pilots found themselves relaying messages from plane to plane. At least one pilot had to go it alone: an Air Force plane loaded with passengers and flying from New Zealand to Antarctica made the 2,000-mile journey over ice and frigid water without radio contact from anyone.
For some scientists the storm turned into a bonanza in spite of the fact that the event was not “official.” Knowing that the solar storm was likely to stir up auroras and some fine scientific obser-
vations, space physicist John Winckler and a team of colleagues from the University of Minnesota braved a frigid night in order to launch a research balloon. A year earlier, Winckler’s group had made perhaps the first “discovery” of the International Geophysical Year during an auroral storm. Launching an instrument-laden balloon within hours of the start of the IGY (which began at midnight, Greenwich/Universal time on July 1, 1957), the Minnesota scientists had detected X rays that seemed to emanate from the aurora. They surmised that energy had been absorbed from a solar storm and was transformed by auroral processes in Earth’s ionosphere to be emitted as X rays. By February 1958, Winckler and colleagues were prepared to follow up their X-ray observations and do the sort of coordinated science that the IGY was designed to promote. Using fresh observations of auroral X rays from the night of February 10 to 11, they compared their data with those from cosmic-ray detectors, as well as radio and magnetic observatories on the ground. The researchers also compiled a synopsis of the space weather storm, detailing the flow of energy and activity from Sun to Earth.2 They estimated that the cloud of solar material that had passed over Earth was 23 million miles wide and 46 millions miles long (half the distance to the Sun).
A century after Carrington and Loomis dissected the great storm of 1859, the link between solar storms, magnetic storms, and man-made technology was obvious, if not well understood. Wires invented to carry the electromagnetic currents of telegraph signals, telephone messages, and electricity—even streetcar and electric train equipment3—also picked up currents from the great generator in the sky (we now know them as geomagnetically induced currents, as noted in Chapter 6). Radio and television signals, as well as radar pulses, could sometimes be disrupted by the manic Sun. And as Brooks speculated in his story about the 1958 magnetic storm, “Nobody knows what kinds of apparatus still undreamed of may come along to be thrown out of whack by their caprices.”
“The recording of this event on a global scale was one of the major achievements of the IGY,” wrote Walter Sullivan. “As with
the thorough examination of a patient—making use of electrocardiograms, a half-dozen laboratory tests, and direct observation—the mass of assembled information may make it possible to diagnose more accurately the exact nature of a magnetic storm.”
One of the most ubiquitous and useful technological tools of the 1950s was the radio wave. Discovered at the end of the nineteenth century and harnessed in the first half of the twentieth, radio waves were used for wireless transmission of music, news, and drama to the public; for ship-to-shore, air-to-ground, and other navigation and transportation-related communications; for the detection of incoming planes and missiles in wartime (via radar); and for transmission of the burgeoning entertainment form of the era, the television program. Radio waves made the world smaller, safer, better informed, and somewhat more entertaining. They also brought scientists and engineers face to face with another aspect of space weather.
At the upper edge of the atmosphere, where Earth’s environment meets the space environment, solar radiation breaks gases into the ions and electrons of plasma, forming a region called the ionosphere. This plasma-filled ionosphere conducts electric current and reflects radio waves, making most modern communications possible. Radio signals bounce off of the seemingly “flat” surface of the ionosphere as if it were a mirror reflecting light, and the behavior of these transmissions can be predicted. This phenomenon allows radio operators to overcome the curvature of Earth and transmit signals over the horizon, bouncing signals off the edge of space to reach distant receivers.
During space weather storms, however, the density of plasma in the ionosphere can be quite variable, becoming agitated by various environmental changes and forming “clumps” of plasma. Disturbed patches of ionospheric plasma swirl around the uppermost reaches of the atmosphere like thunderclouds and weather fronts. The flat ionosphere that was once useful for reflecting radio
waves suddenly becomes rippled like a piece of corrugated cardboard. Light and radio waves get refracted (bent) in a phenomenon known as ionospheric scintillation (similar to the way light is refracted by water, such that a pencil looks bent when it is halfsubmerged in a glass of water). Predicting how, where, and when these distorted radio signals will bounce back to Earth becomes difficult. Since radio transmitters are calibrated to certain frequencies and conditions in the ionosphere—to certain bends and reflections of their signals—space weather scintillation can cause systems to lose their “lock” on certain frequencies.
At other times, the ionosphere can become so excited and dense that it absorbs the signals it usually reflects, causing faded signals and sometimes radio blackouts. During the March 1989 storm, many high-frequency radio channels were unusable for long periods of time. Shortwave radio fadeouts hampered commercial airlines, ship-to-shore radio, and international broadcasts by the BBC World Service, Radio Free Europe, and the Voice of America. In Minnesota, ham radio operators picked up the radio transmissions of the California Highway Patrol, some 1,500 miles away. Television viewers in Key West, Florida, reported watching one network and hearing the audio track from another. Some shortwave transmissions were interrupted for as long as 24 hours.
Similarly, the U.S. Coast Guard’s Long-Range Navigation (LORAN) system was rendered nearly useless for several hours during the March 1989 storm when its very low-frequency signals were blocked due to the sharply increased density of the ionosphere. In a coastal town in California, automatic garage doors began opening and closing on their own. Some people wanted to blame the raging magnetic storm overhead, but it wasn’t the Sun and aurora at work—at least not directly. A U.S. Navy ship cruising offshore had started using a special radio frequency to keep in communication with its coastal base. The only reason the vessel was using that frequency—nearly identical to the frequency used by garage door systems—was that the LORAN system was blacked out by the solar onslaught.
One of the ways to overcome the radio distortion in the ionosphere is to transmit signals at frequencies that pass through it, relaying radio messages through satellites instead of the less predictable atmosphere. And while that method is more effective and precise, it is exponentially more expensive and not without its own set of problems. On rare occasions, turbulence can make the ionosphere opaque to certain radio frequencies, preventing signals from passing through and cutting off communications between ground stations and spacecraft.
More often, space weather makes signals hard to track with precision. Scintillation can be a problem for some users of the Global Positioning System (GPS) and users of satellite phones and television networks. For instance, in 1997, operators working through a performance review for the Federal Aviation Administration lost their lock of GPS signals from four of their five stations during an excruciating 13 minutes. Systems such as guided missiles that depend on extremely precise tracking of radio signals can also have problems because scintillation changes the path of those signals. In a recent report the U.S. Department of Defense estimated that scintillation could cause as much as 27 minutes of delay in the command and control of its Tomahawk cruise missiles.
Even the Sun itself can get involved in breaking up radio communications, as scientists figured out during the tense days of World War II. In 1935, British physicist Robert Watson-Watt produced the first practical radar (radio detection and ranging), allowing operators to locate objects beyond their range of vision by bouncing radio waves against them. Radar can determine the presence and range of an object, its position in space, its size and shape, and its velocity and direction of motion. That was particularly useful for Britain as it struggled to fend off the bombers and fighter planes of the Nazi Luftwaffe.
Late in February 1942, British radar stations watching over the English Channel started picking up severe rushing noises. Their systems periodically became completely inoperative because of a very strong form of radio noise. Operators grew concerned that the Germans were jamming their system and a major attack was
imminent. A physicist in the British Army Operational Research Group, James Stanley Hey, was charged with investigating this jamming of Army radar sets. Hey and colleagues discovered that the Sun was a powerful and highly variable radio transmitter and that sunspots and other forms of solar activity were producing potent radio emissions. The enemy of the radar was not the Germans but the Sun.
The effect persists today. Many satellites are typically placed in geostationary orbits around Earth, orbits that lie in the equatorial plane. During the spring and fall equinoxes, the Sun also passes through this plane (from the perspective of Earth). Once a day the satellites pass in front of the Sun and their signals get lost in the radio noise.
