An image of the sun on May 23, 1967 with a bright area (top, center) where the solar flare occurred on that day. Source: National Solar Observatory Historical Archive, American Geophysical Union
It was during the height of the Cold War and a powerful solar storm could have led to a catastrophic military conflict between the US and the Soviet Union if it weren’t for the US Air Force’s initial efforts to monitor solar activity. On May 23rdIn 1967, a solar storm took place with such great power that it interfered with radar and radio communications in the polar regions and the US Air Force really began to prepare planes for war because of the radars. surveillance of the country being jammed by the Soviet Union. Fortunately, space weather forecasters in the military suspect there could be another cause, and they relay information about the possibility that a solar storm could be the reason radio and radar communications are down. discontinuity. As it turned out, this information was enough to keep the planes on the ground and the US to avoid a potential nuclear arms exchange with the Soviet Union.
Early attempts at sun tracking
The United States military began monitoring solar activity and space weather disturbances in the upper atmosphere in the late 1950s. By the 1960s, the United States Air Force’s Aviation Weather Service United States (AWS) has formed a new branch with the specific purpose of tracking the sun for solar flares that could lead to disruptions on Earth by radio communications and power lines. During the 1960s, AWS established a network of observers in the US and abroad who provided regular input to solar forecasters at the Aerospace Defense Command. North American Headquarters (NORAD). In fact, in 1967, several observatories around the world sent daily reports directly to NORAD solar forecasters.
Daily observations of sunspot numbers since January 1, 1900 by Solar influence data analysis center (SIDC). The thin blue line indicates the daily number of sunspots, while the dark blue line indicates the active annual average. Arrows indicate the duration of the solar storm mentioned in this post (May 23, 1967). Data sources: WDC-SILSO, Royal Observatory of Belgium, Brussels. Last shown date: April 30, 2022. Last map update: May 4, 2022.
The resulting solar storm was a near call
In 1967, solar cycle #20 was increasing in the direction of the sun’s maximum with an increasing number of sunspots, and this cycle is often associated with increased solar activity such as flares. On May 18, 1967, observers detected an unusually large group of sunspots with intense magnetic fields over a region of the sun. By May 23, observers and forecasters noticed that the sun still appeared to be quite active and likely to produce a large solar flare. Observatories in New Mexico and Colorado actually saw a visible flare while a solar radio observatory in Massachusetts reported that the sun was emitting high levels of radio waves. never happend. A major worldwide geomagnetic storm is forecast within 36-48 hours, according to a bulletin from NORAD’s Solar Prediction Center in Colorado Springs, Colorado on May 23:
Notes recorded during May 1967 regarding the solar region where the great fire occurred on 23 Mayrd. Source: National Solar Observatory Historical Archive, American Geophysical Union.
As the solar flare event unfolded on May 23, radars at all three Ballistic Missile Early Warning System (BMEWS) sites in the far Northern hemisphere were disrupted. These radars, designed to detect incoming Soviet missiles, appear to have been jammed. Any attack on these stations – including jamming their radar capabilities – is considered an act of war.
Retired Colonel Arnold L. Snyder, a solar forecaster at NORAD’s Solar Prediction Center, was on duty that day. The tropospheric weather forecaster told him that NORAD Command had inquired about any possible solar activity. Along with information from the Solar Prediction Center, NORAD learned that three BMEWS sites were in sunlight and could receive radio emissions from the sun. These events suggest that the radars are being ‘jammed’ by the sun, not the Soviet Union, Snyder said. As the amount of solar radio emissions decreases, the ‘jamming’ phenomenon also decreases, further suggesting that the main cause is caused by the sun, he said.
For most of the 1960s, the Air Force continuously flew warning planes laden with nuclear weapons. But the commanders, assuming that the BMEWS radars were being jammed by the Russians and unaware of the ongoing solar storm, put additional forces on “ready to sortie” during the particular event. this body. The Air Force did not launch additional aircraft due to information from the Solar Prediction Center to commanders to promptly prevent military action, including the deployment of nuclear weapons.
A report on solar activity May 26 from the Space Disturbance Prediction Center, a civilian forecasting center at the Environmental Science Services Administration (now NOAA). Credit: ESSA / NOAA
Solar flare on May 23rd, 1967 was accompanied by a solar mass launch (CME) that caused a powerful geomagnetic storm to hit Earth about 40 hours later. US radio communications have been disrupted in every conceivable way for almost a week. In fact, this particular solar storm is so powerful that the Northern Lights – usually limited to skywatchers at high latitudes – can be seen as far south as New Mexico.
The solar storm of May 1967 ranks as one of the top storms in the record books. The most powerful solar storm in recorded history is called “The Carrington event“It took place in September 1859. That geomagnetic storm damaged telegraph systems across North America and Europe and the northern lights were visible all the way down to Cuba. A solar storm like today’s Carrington could be devastating due to its reliance on electricity and satellite networks.
Meteorologist Paul Dorian