During the Vietnam War, the United States strategically placed mines in North Vietnamese waters area that were set to detonate when a ship was in close proximity. In August 1972, a large number of these magnetic mines simultaneously started exploding. Upon investigation, the US found out that the cause of these explosions, which were estimated to be as many as 4,000, were not enemy ships. As it turned out, the culprit was located some 93 million miles away: the sun.

Solar Flares of 1972

In August 1972, a powerful historical series of solar storms with an extreme solar flare, solar particle events, and geomagnetic storm components hit the Earth. As defined by NASA,

Solar flares are powerful bursts of energy. Flares and solar eruptions can impact radio communications, electric power grids, navigation signals, and pose risks to spacecraft and astronauts.

That month, the sun unleashed a series of extremely powerful flares after increased solar activities. The burst of energy from these solar flares can be followed by coronal mass ejection (CME). A CME is like a cloud of radioactive particles from the sun expelled into the cold expanse of space at extremely high speeds. So high that normal CME can reach the earth in just one or two days, even when the sun is almost 93 million miles away.