RELATED: Sun Erupts With Biggest Solar Flares of 2016
At the dawn of the space age in the late 1950s, the U.S. military started watching solar activity to make better predictions about when space weather would affect Earth. This expanded into the Air Force's Air Weather Service (AWS) that looked for solar flares starting in the 1960s. Their observers were located around the country and spoke regularly with solar forecasters at the North American Aerospace Defense Command (NORAD), which controls and defends the airspace above North America.
Luckily for history, these reports were often sent daily to NORAD by 1967. On May 18 of that year, observers saw an unusually large group of sunspots in one spot on the sun. Five days later, the storm erupted and was visible to the naked eye in New Mexico and Colorado, according to observatories there. Because the flare was pointed approximately in the direction of the Earth, a coronal mass ejection of solar particles was expected to follow 36-48 hours later and hit our planet.
On the same day -- May 23 -- NORAD's Ballistic Missile Early Warning System's three radars in the north all jammed. A NORAD weather forecaster asked Arnold Synder, the on-duty solar forecaster that day, if the sun was being active at all. "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," said Snyder, who is now a retired colonel, in the same statement.