New research suggests our Sun has the ability to produce “superflares” – bursts of energy and radiation 1,000 times more powerful than regular solar flares. If true, this has implications for how we would protect ourselves from potentially catastrophic solar storms.
The study, to be published in the Astrophysical Journal Letters (a pre-print is available on Arxiv), was led by scientists from the University of Warwick. They looked at a distant binary star called KIC 9655129 in the Milky Way, which is known to have superflares.
These massive bursts were first found in the 1970s, but they were thought to be produced by a different process to regular solar flares. However, this research shows that the physics of superflares on KIC 9655129, noticeably their quasi-periodic pulsation (QPP, meaning almost periodical) spotted by the Kepler space telescope, are similar to the relatively smaller flares seen on the Sun.
“Our research suggests the underlying physics is the same,” lead researcher Chloë Pugh told IFLScience, “and it could be possible for a superflare to occur on the Sun.”
Pugh said the chances of one occuring any time soon were "incredibly unlikely," although it's possible one could occur roughly every 600 years, according to other research.
And there is some evidence for the Sun producing superflares in the past. “Looking at Arctic ice cores, scientists found certain isotopes that suggest a bombardment of radiation, which suggests that this is due to a big solar flare in 700 C.E. and 900 C.E.,” said Pugh. “Not that long ago.”
Satellites in orbit must be turned off or pointed away from the Sun during large solar flare events. Tatiana Shepeleva/Shutterstock
A solar flare pointed in the direction of Earth can cause havoc for satellites and even astronauts in orbit, with an energy equivalent to a 100-million-megaton bomb. We have a variety of space weather prediction centers around the world to help mitigate the effects, such as turning off satellites or pointing them away, but if a storm is powerful enough then the radiation could be too much even for the hardiest of protection measures.
The largest solar storm on record is the 1859 Carrington event, which reportedly set telegraph wires on fire, although it’s unclear if this was a superflare. Today, considering how much more ubiquitous technology is, the damage would potentially be much more severe from a similar storm or a superflare, with an estimated energy of a 1-billion-megaton bomb for the latter. All hope is not lost, though.
Superflares seem to be preceded by a huge “active region,” like a sunspot. On some stars this can cover nearly 50 percent of the star’s surface. On the Sun, according to Pugh, this could be an eighth of a quarter of the surface, although this is a very loose estimation. These active regions can persist for days, releasing a superflare seemingly at random, but within this time scale. So there would be some indication when one might be about to occur, and we could do our best to mitigate its effects if it was pointed in our direction.
Pugh notes there is no need for alarm just yet, but the research does at least suggest a possibly unrealized power our Sun possesses.