The Sun may be capable of producing solar flares at least 10-20 times stronger than anything observed in modern times, according to new research. This follows on the heels of recent research done using NASA’s Kepler Space Telescope that observed Sun-like stars releasing solar flares 10,000 times greater than any yet observed from our Sun.

Back in 774-775 AD something caused a significant spike in the atmospheric carbon-14 levels observed in tree rings from that time period. Carbon-14 (14C) is a form of carbon that is created from high-energy radiation hitting the Earth’s upper atmosphere, where it converts nitrogen-14 into 14C. This is then taken up by plants through photosynthesis.

The 14C spike was discovered earlier this year in research being done on tree rings in Japanese cedars dating from 774–75. The researchers were unable to come up with an explanation for the 14C spike, all of the possible explanations seemed very unlikely.

But Adrian Melott, a physicist at the University of Kansas in Lawrence, and lead author of the new study, says “that the Japanese team made a miscalculation in ruling out one of these possibilities — a giant solar storm.”

According to Melott, the problem is that the previous researchers “treated solar storms as if they shone like light bulbs, radiating energy uniformly in all directions. But actually, they produce ‘blobs’ of energetic plasma that explode outwards unevenly. Adjusting for that, he says, reduces the size of the solar storm needed to produce the observed 14C spike from 1,000 times larger than anything known, to only 10–20 times larger — meaning that a giant solar storm is suddenly back on the table as a reasonable explanation.”

And as recent observations from NASA’s Kepler space telescope have shown, Sun-like stars are completely capable of producing truly gargantuan super flares like the proposed one at least every few hundred to thousand years. Of course storms this big haven’t yet been observed in modern times, it’s possible the Sun is different in some ways from the stars observed by Kepler, “but it suggests it’s reasonable”, Melott says.

The other possible explanations seem to be much less likely. It’s possible that radiation from an exploding supernova would function the same, but the “supernova would have to have been within about 100 light years,” Melott says. “Such an event would have been blindingly bright in the sky, much brighter than a full Moon. It would have been bright like that for months and could not have failed to be noted by every civilization on Earth.”

The other primary possibility is that it was caused by a gamma-ray burst from a distant supernova. “But such bursts are rare and produce searchlight-like beams of radiation unlikely to hit us. I don’t think it’s likely,” Melott says.

A solar flare powerful enough to create the 774–75 event would completely dwarf the solar flares that have been observed in modern times. Such a flare would have a profound effect on modern civilization if it were to occur now. It would be 60 times stronger than the solar storm of 1989 that took almost all of Quebec off the grid for over nine hours and caused $3-6 billion dollars in damages. “Multiply that by 60 and add two decades of increased technological vulnerability, and the effects might be disastrous. A lot of people could die,” Melott says. “You could have power out for months or longer — no refrigerated food, no food being transported to all the people who live in big cities.”

The new research was just published in the journal Nature.

Source: Nature

Image Credits: Hinode, JAXA/NASA; Cooper Downs, Predictive Science Inc