We are extremely blessed to occupy this exact place in the universe at this exact moment, when our Sun has been unusually "quiet" in astronomical terms. No major solar events have occurred that could have destroyed humanity or, more recently, fried our electronics and sent us back to the Stone Age.
This becomes more apparent as scientists use ever-more sophisticated, far-seeing technology to study other stars. What we're finding out is how incredibly lucky we are. Other stars like our Sun (called "G-type stars") regularly emit devastating solar flares that would extinguish life on most planets unlucky enough to get in the way of one of these "superflares."
For some reason, our Sun has spared us these regular solar events. But that luck may not last forever.
"A study as recent as December 2024 analyzed 56,450 sun-like stars using data from the Kepler space telescope and found that 20 percent of them had produced these superflares within the measured timeframe," writes Darren Orf in Popular Mechanics. "Of that 20 percent, superflares occurred on average every century."
Many stellar scientists think that's far too high. But the really strange part of the equation is that our Sun appears to be the only quiet one among those 56,450 G-type stars.
Now, a new study by scientists at the Max Planck Institute and the University of Colorado Boulder found that our Sun does carry the potential for one of these catastrophic superflares. In fact, Earth almost succumbed to one of those flares in 1947.
Solar flares are formed when magnetic fields "twist" and "reorganize over complex 'active regions,' which contain the Sun’s most active sunspots," writes Orf. "Each eruption leaves behind a flare ribbon: a residual glow in the chromosphere, the second layer of the Sun’s atmosphere."
The bigger the ribbon, the bigger the flare, and because of that, scientists use ribbon area to gauge a flare's energy. Once scientists were able to correlate ribbon size with energy released by flares, they looked at the 400-year historical record and could figure out the size of the "active regions" and hence the energy released in large flares.
Two events stood out: the Carrington Event of 1859, where a flare so powerful that it set telegraph wires on fire struck the Earth, and "The Great Sunspot of 1947." That spot "covered 0.6 percent of the solar disk, or roughly 40 times the diameter of the Earth," writes Orf. A flare would have released the energy of a trillion hydrogen bombs if its magnetic field lines had snapped, releasing an octillion joules of energy.
“Of course, we knew that no superflares had occurred during the observation period,” Max Planck’s Natalie Krivova, lead author of the study, said in a press statement. “But the statistical relationship we found between the released energy and the size of the active region should hold true for more powerful events as well.”
The Carrington Event is often called “history’s greatest solar storm,” and for good reason. The storm reportedly set fire to telegraph wires and generated aurorae visible all the way to the equator. However, after analyzing the data, the closest call actually occurred in 1947. According to the study, the Great Sunspot of 1947 covered 0.6 percent of the solar disk, or roughly 40 times the diameter of the Earth. The magnetic energy coiled in a region that size reached the low end of what qualifies as a superflare, but the Sun simply didn’t pull the trigger. It’s worth asking what happens when something like that does happen.
“The 1947 spot, the largest in the last century, yields the highest possible flare energy within our framework,” the authors write. “This range overlaps with the lower limit of the superflare regime inferred from stellar statistics, suggesting that the Sun could, in principle, reach this level, albeit extremely rarely."
We've had minor solar flares disrupt satellite communications and wreak havoc on our phones. A superflare would permanently fry every satellite in orbit and cook any astronauts unlucky enough to be in space. It would also destroy even super-shielded electronics on Earth, blowing up the banking system and sending us to a time before the Electronic Age.
We live in the sticks of the galaxy; a very unexciting edge of one of the Milky Way's spiral arms in a very ordinary section of space. No doubt, this has aided our evolution immensely, as we've missed several planet-killing events, even beyond comets and asteroids. Superflares may be rare, but they're not impossible.
For that reason alone, we need to get off this rock and find other places we can lay our heads.
