66 Scientific American, December 2021huge influx of solar particles. “It’s safer to assume all these
events were big geomagnetic storms,” Thomas says.
If that link is correct, it suggests that in the past 10,000
years alone, Earth has been battered by at least three solar
superflares. (Evidence of more may eventually be found in
the 84 percent of available tree-ring data that have yet to be
analyzed for carbon 14 spikes.) “For there only to be one in
the past 10,000 years didn’t really seem realistic,” Pearson
says. “But up until this point, it could have just been a one-
off. Now that we’ve found two more, I’m not sure that it’s sur-
prising—but it may be concerning.”
The major worry is that if such an event happened today,
it could be devastating to satellites in orbit and infrastruc-
ture on the ground. In March 1989 a geomagnetic storm
much weaker than the Carrington Event caused a 12-hour
blackout in Quebec when it overloaded the entire prov-
ince’s power grid. Today a geomagnetic storm resulting
from a Miyake event would probably cause many more
widespread effects, including potentially catastrophic pow-
er grid and satellite failures.
Sangeetha Abdu Jyothi of the University of California,
Irvine, recently calculated that a Carrington Event–level
storm today could even cause an “Internet apocalypse.”
Energetic particles from such a storm could knock out
undersea cables between countries, disrupting worldwide
Internet traffic for weeks or possibly months. In the U.S.
alone, such a disaster could cost $7 billion a day, Abdu Jyo-
thi estimates. Something stronger, such as a Miyake event,
could cause almost incalculable damage. “For something at
a Carrington-scale, we could possibly recover because our
data themselves will not be erased,” Abdu Jyothi says. “With
something 10 or 100 times stronger, I don’t know. I don’t
think anybody has simulated that. I suspect it would cause
significant data loss. We could lose all our records, bank
information and critical health information and not have
anything to go back to.”
The odds that our global civilization will suffer a dark
age from a Miyake event seems remote for the time being.
But some estimates suggest the chance of a Carrington-
level event may be as much as 12 percent in the next
decade. We can prepare for something of this magnitude
by monitoring solar activity to shut down satellites and
power grids ahead of the arrival of a superflare and its
ensuing geomagnetic storm. But a Miyake event may be
more difficult to protect against.
Meanwhile scientists continue to find evidence of addi-
tional extreme solar events in ancient tree rings and ice
cores. “We’re starting to realize that the sun can be much
more energetic and active than we thought,” Thomas says.
“When people were studying these superflares on other
stars, one discussion was whether the sun could do this.
From these historical records, it seems the sun is capable
of getting into that range.”
FROM OUR ARCHIVES
The Mysterious Origins of Solar Flares. Gordon D. Holman; April 2006.
scientificamerican.com/magazine/sa