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Superstorms That Rage in Silence
May 1968 Popular Mechanics

May 1968 Popular Mechanics
May 1968 Popular Mechanics - RF Cafe[Table of Contents]
Wax nostalgic over early technology. See articles from Popular Mechanics, published 1902 - 2021. All copyrights are hereby acknowledged.

You have likely heard of the International Geophysical Year (year and a half, actually), which was timed to coincide with maximum solar activity beginning in June 30, 1957, but have you heard of the Second Polar Year, a 13-month period that began in August 1932? It was conducted at a time when long range radio communications was becoming a major geopolitical necessity and scientists needed to better understand the phenomena of ionization in the Earth's upper atmosphere (named as a result - you guessed it - the ionosphere). Critical World War II radio communications were hampered by atmospheric electrical disturbances; likewise during the Korean War. When the Space Age was in its early years, learning about how radiation in all forms affect both electrical and biological (i.e., human) entities was essential in order to mitigate harmful effects and assure their safety. This "Superstorms That Rage in Silence" article in a 1968 issue of Popular Mechanics magazine discusses the consequences of solar activity on Earth-based systems - particularly the power distribution grid.

Superstorms that Rage in Silence

Eruptive arch prominence, a hydrogen gas cloud - RF Cafe

An eruptive arch prominence, a hydrogen gas cloud, rises more than 60,000 miles above surface of sun.

By Lyman M. Nash

Photos by Sacramento Peak Observatory, U.S. Air Force Office of Aerospace Research

Magnetic storms black out cities, raise havoc with radio and television, and cut off airline pilots from their ground communication. Solar flares are the cause - and new disturbances lie ahead.

Shortly before 8:30 on the crisp Monday evening of Feb. 10, a storm of savage intensity struck New York City and within a minute engulfed the entire earth. Transatlantic radio was wiped out. Ships lost contact with shore stations and with each other. Airplanes aloft were limited to line-of-sight communications only. Teletype and Western Union messages were so garbled translation was often impossible. Low-altitude radiation tripled, while tremendous electric currents surging beneath the sea turned oceans into huge storage batteries.

The storm was the worst of its kind ever recorded, yet few people knew about it until they read their morning paper. Visible evidence of its fury was limited to wild scratchings on magnetograph charts, wavering compass needles and a magnificent auroral display stretching from polar regions almost to the equator.

No doubt such storms wracked the Earth long before the first life struggled from the primordial sea. Their existence, however, went virtually unnoticed until about a century ago, when the equipment they affect came into common use.

Sun at Solar Minimum - RF Cafe

Sun at Solar Minimum: Few sunspots (flares) are seen. In 11-year cycle, sun returns to solar maximum.

Solar Maximum - RF Cafe

Solar Maximum: Bright areas (flares) emit Gamma and X-rays, disturb ionosphere, cause radio blackouts.

Since then magnetic storms, as they are called, have become a growing nuisance, periodically interrupting the smooth conduct of our electrically oriented lives. They cancel long distance phone calls, scramble telegrams and silence the best radios. They build up power overloads to plunge whole cities into darkness. Nor is the situation likely to get better. As we become more electromagnetically sophisticated, we will be increasingly at their mercy.

Each second the sun blows a million tons of matter into space. These charged particles spread out in all directions to form the "solar wind." When this nears the Earth, the latter's magnetic field deflects the particles into the Van Allen belts. Save for a few high-energy particles that leak through, our magnetic field shields us from cosmic radiation.

What, then, causes magnetic storms? The only thing generally agreed is that they stem from solar flares - explosions releasing Energy millions of times greater than the most powerful hydrogen bomb. This energy, in the shape of a gigantic cloud of charged particles, hurtles through space at 1000 miles per second. If on a collision course with earth, it deals the planet such a magnetic jolt that magnetic pull might vary more than 10 per cent, compass needles will swing seven or eight degrees, and the ionosphere will go haywire.

Magnetic storms occur most frequently and are most violent when sunspot activity is at a peak sunspots wax, wane, and wax again over a period that averages out at 11 years, though as many as 17 years have elapsed between peak periods. At the start of a cycle, spots appear only in the sun's upper latitudes. As activity increases they show up ever closer to the equator. After building to a peak, which may see the sun literally speckled with spots, they gradually subside. Midway through a cycle there may be no sunspots at all.

Sunspots were first observed in the early 1600s, shortly after invention of the telescope. Beyond the discovery that they have a magnetic field thousands of times stronger than the sun itself, we don't know much more about them today. They appear dark simply because they are 2000° cooler than the rest of the sun's surface, or "photo-sphere," where the temperature is 6000° C. (about 10,000° F.) Seen alone, a sunspot would glow far brighter than the brightest arc lamp.

When seen through a helioscope, which permits telescopic viewing of the sun without injury to the eye, a sunspot looks like a vortex with stuff falling into it. Some are so large they cover billions of square miles of the photosphere. A particular spot might last less than a day, or be visible for months. Some emit flares, some do not, but apparently only flaring sunspots cause magnetic storms.

The strange effects of sunspots and magnetic storms first came under international study during the Second Polar Year, a 13-month period from Aug. 1, 1932, to Aug. 31, 1933. (The Polar Year, a half-century before, had confined itself mainly to terrestrial matters.) But a worldwide depression put a financial crimp on the project, and solar activity was at a minimum, so there weren't many sunspots to study. Despite this, the knowledge acquired when applied to radio alone was worth many millions of dollars.

A quarter-century later the International Geophysical Year began. Timed to coincide with maximum solar activity, it started June 30, 1957, and ended Dec. 31, 1958. And it kicked off, magnetically speaking, with a bang.

At 4:00 a.m. on the first day a magnetic storm severely disrupted radio communication between America and Europe. At 5:00 a.m. a brilliant aurora, thousands of miles long, swept across the northern United States. Unfortunately, the storm came too soon for many of the IGY's more elaborate programs.

Which is why, in Feb. 1958, eager scientists around the world had their eyes and ears trained on the sun. Early that month a group of sunspots covering three billion square miles began developing near the sun's central meridian. Then, at five minutes past 1:00 EST, on Sunday afternoon, Feb. 9, the Harvard Radio Astronomy Station at Fort Davis, Tex., picked up a loud crackling sound on 458 megacycles, a frequency favored by the sun. Three minutes later visual observers, scattered over the daylight half of the earth, saw a solar flare of dazzling brilliance erupt near those sunspots, one of the largest groups ever seen.

As the flare developed the radio noise grew to a steady roar and was soon heard on other frequencies, as well. After almost two hours, the flare died and the solar radio quit broadcasting. For the sun, at least, the show was over.

According to the most widely accepted theory, some solar flares emit only radio noise while others also eject what geophysicists call "corpuscles," submicroscopic charged particles. If this flare had ejected such a cloud - aimed at Earth - a magnetic storm could be expected in about a day.

At the IGY World Warning Agency, Fort Belvoir, Va., an alert was sent to scientists of the 66 nations taking part advising them to look for anything out of the geophysical norm. But it was decided not to call a Special World Interval, which automatically would put into operation costly and highly complex experiments. Forty larger flares already had been seen during the IGY, and there had been seven SWIs.

As it turned out, this was a mistake. The flare had indeed ejected a cloud of corpuscles-headed straight for Earth.

Twenty-eight hours later, at precisely 8:26 p.m. New York time, Feb. 10, the cloud and the Earth arrived at the same point in space, causing a slight jiggle on the recording charts of magnetic instruments. The jiggles increased rapidly, and by 8:49 were sweeping right off the page. A bright aurora appeared over Minneapolis, and all magnetic hell broke loose.

Normally auroras are confined to two narrow bands encircling the globe about 1700 miles from either pole. Aurora borealis, in the northern hemisphere, passes through central Alaska, Hudson Bay, southern Greenland, upper Scandinavia and Siberia. In the southern hemisphere aurora australis skirts Antarctica.

Cloud of charged particles, striking Earth in 1958 - RF Cafe

Cloud of charged particles, striking Earth in 1958, caused violent magnetic storm and radio blackouts.

During a magnetic storm, though, the auroras spread into the temperate zones. If the storm is particularly fierce, auroras can even be seen flickering briefly yet brightly deep into the tropics.

Although auroras have been well studied, they are a long way from being understood, and there is no foolproof theory to explain them. About all that is known for sure is that the presence of an aurora indicates a state of turbulence in the ionosphere, a region above the stratosphere containing tiny particles of electrically charged air.

Within the ionosphere are the Kennelly-Heaviside and Appleton layers which act as mirrors, reflecting radio waves of certain frequencies back to earth. But for them, a series of relay stations would be needed to broadcast long distances, since radio waves travel in a straight line and do not follow the curvature of the Earth. During a magnetic storm, however, the layers seem to go to pieces. Radio waves are gobbled up by the ionosphere and distant radio communication ceases.

So at 8:50 p.m., with the aurora spreading, transatlantic radio contact abruptly faded. Radio companies tried to keep in touch with Paris by routing messages to South America and over to Tangiers, thus avoiding the turbulent ionosphere above the North Atlantic. Sporadic contact was maintained in this manner until 11:00, then for the next hour and a half there was no contact at all.

Meanwhile, the breathtaking aurora continued growing and at 9:00 p.m., was seen as a faint pinkish glow as far south as Georgia. As sheets of electricity tormenting the ionosphere were duplicated within the Earth, submarine cables began being affected. At 9:01 the Bell System's cables between Newfoundland and Scotland packed a potential of 2650 volts. American voices heard in Europe varied from whispers to ear-shattering squawks.

Still the storm's fury increased. Power overloads started tripping circuit breakers and lights began blinking out on both sides of the Atlantic.

At 1:45 on the morning of Feb. 11, a faint aurora was seen near Mexico City. At 2:00 a.m. the junior third officer aboard the President Taylor, steaming off the Mexican coast on the same latitude, recorded that the northern sky was aglow in red.

By then feeble radio contact had been regained with Paris, via South America-Tangiers. But the countless ships plying the North Atlantic and the 100 or so airplanes flying above it were still groping in radio blindness. Luckily, there was no marine disaster necessitating an SOS, and pilots managed to keep pretty well on course and out of danger by relaying messages from plane to plane.

At dawn on Feb. 11 the ionosphere reconstituted itself and the layers resumed reflecting normally. However, that night radio communication was once more erratic over the North Atlantic, and auroras were seen in several places. Not until 10:00 a.m. on the 12th was the great magnetic storm of 1958 declared over.

To produce all the phenomena observed it was estimated the cloud of charged particles encountered by the Earth must have been 46 million miles long and 23 million miles wide. The aurora it caused was calculated as being 5800 miles long in an east-west direction, 400 miles wide, 360 miles thick, and starting at an altitude of 120 miles.

While the storm threw some new light on the nature of the ionosphere and the Earth's magnetic field, it left most old questions unanswered. We still don't know what makes aurora's shine, or what causes the ionosphere to go haywire during a magnetic storm. Sunspots remain as mysterious as ever, though it is now thought that a sudden breakdown of a spot's magnetic field permits the flare's energy to escape into space. Some scientists feel that if we ever get to the bottom of these mysteries we may be well on the way to solving the secret of the universe. One thing is certain. When solar activity again reaches a peak and the sun is dotted with spots, there will be more magnetic storms, perhaps even greater than 1958. If the sun holds to schedule, that should happen around 1969.

 

 

Posted October 26, 2023

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