A superflare is a massive solar flare that can release as much energy as a tenth of the total output of the Sun in a single event. These flares are thought to be caused by a sudden release of magnetic energy stored in the Sun’s atmosphere. Superflares are rare events, but when they occur, they can cause widespread disruption to power grids and communications systems on Earth.
Superflares were first identified in 1992, when Japanese astronomers observed an unusually large flare on the star AD Leonis. This event was later found to have released about 10^32 ergs of energy – more than a hundred times more than any known solar flare. Since then, several more superflares have been observed on other stars, including our own Sun.
The most famous superflare occurred on September 1st, 1859 – an event now known as the Carrington Event. This flare was so powerful that it caused aurorae to be seen around the world, even at latitudes where they are normally not visible. It also induced electrical currents in telegraph wires strong enough to set fire to some telegraph offices!
More recently, in 2012, another superflare was detected on the star KIC 8462852 – otherwise known as “Tabby’s Star” or “Boyajian’s Star”. This event was even more powerful than the Carrington Event, releasing up to 10^36 ergs of energy (a thousand times more than previously thought possible). Thankfully, this star is much further away from us than our own Sun, so we didn’t experience any direct effects from this event. However, it does raise the possibility that such events could occur closer to home with devastating consequences.
There is currently no way to predict when a superflare might occur; however, if one did happen tomorrow, we would be woefully unprepared for its effects. The good news is that there are steps we can take now to mitigate these risks; for example, by hardening our critical infrastructure against electromagnetic pulses (EMP), which are produced by superflares. With proper preparation, we can ensure that future superflares don’t cause too much damage here on Earth.