This relatively small solar flare from October – the bright flash in the centre spotted by NASA’s Solar Dynamics Observatory – would be dwarfed by a superflare
NASA/SDO
The recent discovery of superflares occurring on sun-like stars at a frequency of once per century has raised concerns about the potential impact of such events on Earth. These superflares, which are extremely powerful bursts of radiation, could be accompanied by particle storms that have the potential to disrupt electronics and communication systems on our planet.
Historical records indicate that the sun produced a massive solar flare in 1859, known as the Carrington event, which was followed by a coronal mass ejection (CME) that caused an intense geomagnetic storm on Earth. If a similar event were to occur today, it could have devastating consequences for modern technology.
Studies of radioactive isotopes in tree rings and ice cores suggest that Earth has experienced even more powerful solar storms in the past, although it remains unclear whether these were the result of single large outbursts or multiple smaller events. The frequency of these events, combined with observations of superflares on other stars, indicates that such giant bursts occur every few hundred to thousand years.
A recent survey led by Ilya Usoskin from the University of Oulu in Finland analyzed data from 56,450 stars and found that superflares are more common on sun-like stars than previously thought, occurring once every one or two centuries. This raises concerns about the possibility of a superflare from the sun occurring in the near future.
While the energy levels of these superflares far exceed any observed from the sun, it is uncertain whether they also produce large particle storms similar to those recorded on Earth. The discrepancy between the frequency of superflares and extreme solar storms poses a challenge to current understanding of solar activity.
Mathew Owens from the University of Reading acknowledges the significance of the survey in detecting flares with increased sensitivity but notes that further research is needed to understand the implications for the sun’s flaring activity. The rotation rate of stars, which influences magnetic field generation and flaring activity, is a key factor that requires more detailed investigation.
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