A recent study linked a massive solar storm to a four-decade-old naval mystery.
Sea mines that mysteriously detonated in 1972 are now being linked to a large solar flare.
On Aug. 4, 1972, U.S. pilots buzzing near the Haiphong harbor in North Vietnam began seeing something rather off-putting in the water below. Numerous sea mines began mysteriously exploding — untouched and unwarranted.
Now, over four decades removed from the event, researchers have dug into the mystery and linked the detonation of the mines to a massive solar storm, according to a recent commentary in the journal Space Weather.
The group, led by the University of Colorado's Delores Kipp, suggested that the abnormally strong solar storm was powerful enough to trigger magnetic sensors in the mines, which were rigged to trip in response to magnetic, acoustic and pressure signatures given off by passing ships.
Knipp served 22 years in the U.S. Air Force and always had a "passion for rooting around in dark, dusty archives," she said in a CU news release. Her interest in the 1972 event was piqued when a colleague from NOAA's Space Weather Prediction Center mentioned that he saw a mixed group of navy men and others in dark suits visit with his boss.
While her colleague didn't know the extent of the meeting, he knew it dealt with a recent solar storm and the implications it had on the military.
Knipp was able to track down a navy report declassified in 1990 that detailed sporadic and spontaneous detonation of dozens of sea mines in Asia.
What she wasn't expecting was for the naval report to link those detonations to solar activity.
“I started reading this report, and I said, ‘Wow, this really happened,’” said Knipp.
To get a better idea of the solar activity when the explosions were triggered, Knipp and her colleagues reached out to scientists in the U.S., Japan and Europe to track down reports, most of which had been filed away and gone untouched for some time.
What they obtained showed ground-based observations recorded four solar flares between Aug. 2-4. The third one was a monster that they think produced a coronal mass ejection, or massive expulsions of plasma and magnetic field from the sun, NOAA's Space Weather Prediction Center defines.
The typical time it takes for the Sun's ejection to reach the Earth is about three days. This one took 15 hours.
When the material blasted from the sun arrived, it trounced Earth's magnetosphere, triggering the sea mines and causing major fluctuations in northern U.S. and Canadian power grids.
To emphasize the sheer enormity of the 1972 solar storm, Knipp compared it to that of the 1859 Carrington event — an event NASA calls the mother of recorded solar storms.
"In the 160-year record of geomagnetic storms, the Carrington event is the biggest," David Hathaway, the solar physics lead at NASA's Marshall Space Flight Center, said in 2008.
Hathaway added that "the Carrington event sticks out as the biggest in 500 years and nearly twice as big as the runner-up," with little information known about the 1972 storm.
As for the 1972 solar storm, NASA holds it as legendary because it happened between the Apollo 16 and 17 missions.
The sea mine explosions should serve as a warning to society today, Knipp adds. With people far more dependent on satellites to carry communication and navigation, potential solar storms could cause major problems if a satellite were to be in the path of a flare.