London, August 24 : New calculations have suggested that some solar flares may be caused by dark matter particles called axions spewing out from the centre of the Sun.
Solar flares are sudden changes in the Sun's brightness thought to be caused when twisted magnetic fields on the Sun snap and reconnect explosively.
But, according to a report in New Scientist, they could also be caused by dark matter, the mysterious entity that makes up most of the universe's mass - if it is made up of theoretical particles called axions.
Axions were proposed in the 1970s to help explain the mystery of why our universe is made mostly of matter and not antimatter.
They should be produced deep inside the Sun and should interact with some of the Sun's magnetic fields as they stream outwards, producing flares that are bright at X-ray wavelengths. Physicists had predicted that these axion-generated flares would have certain traits - the flares' X-ray photons were expected to travel radially outwards from the Sun, for example.
But observations showed they came out at all angles.
Now, researchers led by Konstantin Zioutas of the University of Patras in Greece, have said that they have solved such discrepancies.
In their scenario, the first X-rays produced by axions would ionise surrounding matter.
The electrons freed in the process would then cause subsequent X-rays to scatter, explaining why the photons show no preferred direction when leaving the Sun. Zioutas said that analysing flares in detail would indicate the depths at which they formed in the Sun.
That in turn could shed light on how massive axions are, since their mass is related to the density of the solar plasma at which they would be able to produce X-ray photons. With the axion's mass, cosmologists could use estimates of how many were produced in the early universe to figure out what fraction of dark matter is made of axions and what is made of other candidates, such as particles known as WIMPs.