We have long known that the Sun is active. It “flares” quite often, sending huge amounts of energy off in a certain direction - sometimes directly at Earth. But we also know that, compared to other Sun-like stars, it seems relatively quiet, and not capable of producing the “superflares” we sometimes see in its stellar equivalents. That sounds like great news for humanity, and some scientists have even argued that lack of superflares was a critical impetus for the development of complex life on Earth. But a new paper from Natalie Krivova of the Max Planck Institute for Solar System Research and her co-authors in the journal Philosophical Transactions A calls the assumption that our Sun is incapable of such dramatic outbursts into question. That also means that, eventually, our highly technological society could bear the brunt of one of them.

Scientists have been collecting data on the Sun for decades, and one of the most interesting features they watch out for are solar flares. These massive outbursts of energy occur when the twisted magnetic fields located in what are known as the Sun’s “Active Regions” (ARs) snap and reconnect, releasing a huge amount of stored energy. Commonly known as “sunspots”, ARs also leave behind a residual glowing area known as “flare ribbons” that occur after their high-power snap-back.

Using data collected by NASA’s Solar Dynamics Observatory between 2010 and 2016, the authors analyzed what they believed to be a critical relationship - between the total area of an Active Region, the size of its resultant flare ribbons, and the total energy released during their creation. They found a very accurate statistical correlation that also makes sense intuitively - the larger the active region, the larger the ribbon area, and the more maximum potential flare energy. And critically, they found the flare energy scales exponentially with the ribbon area...