Spaceflight Insider

Our Spaceflight Heritage: The day the Sun almost caused World War III

Clear AFS site BMEWS Project for possible World War III

Three of the huge AN/FPS-50 radars, BMEWS Site 2, near Anderson, Alaska, in 1962. Photo Credit: LOC

In the famous Drake Equation, a mathematical formula designed to determine the number of technological civilizations in the Milky Way galaxy (see this clip from the 1980 science television series Cosmos, where Carl Sagan adroitly explains its parameters), the factor L denotes the lifetime that a technological civilization will be sending signals into space.

At present, we have but one actual data point to fill in that part of the Drake Equation, namely humanity. We have been transmitting electromagnetic signals into the galaxy, inadvertently and otherwise, for just over a century now. However, had history gone a bit different on one spring day in 1967, we – or perhaps some other wiser and more advanced species – could have plugged in a definite number for L denoting the end point of our civilization’s technological lifetime. For on that day, one member nation of the Cold War almost launched a nuclear strike on its chief rival, and all because of a storm from deep space.

The 1967 solar storm that almost started World War III.

A view of the Sun on May 23, 1967, in a narrow visible wavelength of light called H-alpha. The bright region in the top center region of brightness shows the area where the large flare occurred. Photo Credit: National Solar Observatory historical archive.

Space Weather, a journal of the American Geophysical Union (AGU), recently accepted for publication a new paper which reveals publicly for the first time how a solar storm that struck Earth in late May 1967 caused the jamming of key American military radar and radio communications in the Arctic. This action was initially interpreted as a sign that the Soviet Union was about to launch a surprise nuclear missile attack on the United States. The U.S. Air Force had even begun to prepare their aircraft for a nuclear response – until a group of military space weather forecasters alerted those in command that it was very likely the Sun and not the Soviets who were causing the mechanical interference.

How close humanity had come to World War III was revealed in detail by Delores Knipp, a space physicist at the University of Colorado in Boulder with their Department of Aerospace Engineering Sciences, and lead author of the new study. She will also give a presentation about this bit of little-known history on August 10, 2016, at the High Altitude Observatory at the National Center for Atmospheric Research in Boulder, Colorado.

“Had it not been for the fact that we had invested very early on in solar and geomagnetic storm observations and forecasting, the impact [of the storm] likely would have been much greater,” said Knipp in a joint news release on August 9 by the AGU and the University of Colorado Boulder. “This was a lesson learned in how important it is to be prepared.”

Since the start of the Cold War in the late 1940s, when the U.S. and U.S.S.R. had developed nuclear weapons and began to stockpile them, large radar facilities, known as Ballistic Missile Early Warning System (BMEWS), were placed in strategic locations in the far Northern Hemisphere to alert U.S. military forces in the event the Soviet Union decided to use their weapons against their geopolitical rivals. Such an attack would most likely take the shortest route from the U.S.S.R. to the United States: Over the Arctic Circle.

One concern U.S. military officials had was the possibility that the Soviets would find a way to “blind” their electronic sentries by interfering with the radar and radio frequencies of the BMEWS and other military watch posts. This scenario would give the Soviets enough time to launch a nuclear strike with both bomber aircraft and missiles so that the U.S. forces would not have sufficient time for a proper response in kind: A definite unbalance to the concept of MAD, or Mutually Assured Destruction. Therefore, any jamming of the BMEWS was seen as an act of war.

Thus the stage was set when on May 18, 1967, an exceptionally large group of sunspots with intense magnetic fields had appeared in a region of the Sun’s photosphere facing Earth. At the same time, a new branch of the USAF’s Air Weather Service (AWS) was providing regular input to solar forecasters at the North American Aerospace Defense Command (NORAD) – a U.S. and Canadian organization that defends and controls the airspace above North America. The AWS was receiving reports from their various observatories across the globe that the sunspots would likely create an intense burst of radiation known as a solar flare that would impact our planet within days. It was known by then that these geomagnetic storms, if severe enough, could disrupt radio communications and power line transmissions – and military radars.

Map of PAVE-PAWS/BMEWS sites in readiness of World War III.

Map of BMEWS sites. Image Credit: U.S. Gov.

When the storm from the Sun hit Earth on May 23, 1967, three BMEWS sites at Clear Air Force Station in Alaska, Thule Air Base in Greenland, and Fylingdales in the United Kingdom, began to see their radar systems being interfered with. The American military’s initial response was that the Soviets were somehow causing this and began to prepare for a retaliatory nuclear strike.

“This is a grave situation,” Knipp said. “But here’s where the story turns: Things were going horribly wrong, and then something goes commendably right.”

On duty that day at NORAD’s Solar Forecast Center was (Retired) Colonel Arnold L. Snyder, a solar forecaster. The AWS’ tropospheric weather forecaster had informed him that the NORAD Command Post had inquired about any solar activity currently going on.

“I specifically recall responding with excitement, ‘Yes, half the Sun has blown away,’ and then related the event details in a calmer, more quantitative way,” Snyder said.

NORAD then learned that the three BMEWS sites being affected were also in daylight, meaning their problems could be coming directly from that yellow dwarf star 93 million miles (150 million kilometers) distant and not the U.S.S.R. Their suspicions were confirmed when the radar “jamming” diminished as the solar storm also weakened. The USAF subsequently “stood down”, averting what could have been a civilization-ending catastrophe. The geomagnetic storm that caused the initial crisis would carry on for almost an entire week, disrupting radio communications and creating aurorae borealis (a.k.a. Northern Lights) that were seen as far south as New Mexico.

Snyder and the other authors of the paper state that it was “the military’s correct diagnosis of the solar storm that prevented the event from becoming a disaster.” The events of May 23, 1967, eventually led to the U.S. military taking solar storms into more serious consideration and vastly improving their space weather forecasting system so that what happened almost fifty years ago does not occur again.


Larry Klaes is an author and freelance journalist specializing in news and educational work on the sciences. Klae's past endeavors include editor of SETIQuest magazine and President of the Boston chapter of the National Space Society (NSS). Klaes joined SpaceFlight Insider in 2016.

Reader Comments

Marlene E. Arenas Fierro

How much might affect the geometric storms to the new comunication’s satellites in the future? Don’t only to the magnetic zones of the world, the satellites and other spacecrafts willbe first and how we could solve this big problem?
Excellent article.

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