Sun, while shifting from its one activity cycle to another, may not be as calm as the scientists thought it was, new research has found. The reason behind the scientists'assumption of a calm sun was that solar activity changes in 11-year cycles.
However, this did not turn out to be the case. The study conducted by Juha Kallunki, Merja Tornikoski, and Irene Björklund, researchers at Metsähovi Radio Observatory helped find three explanations for radio brightenings.
The scientists during the study examined the solar radio maps, which showed active areas or radio brightening, detected by the Metsähovi Radio Observatory. They also compared the maps with the data collected by a satellite which observes the sun in the ultraviolet range. Offering the first explanation, they said that some brightenings noticed in the polar areas on the maps could be identified as coronal holes. These holes eject particles that can cause auroras upon entering Earth’s atmosphere.
Putting out the second explanation, the researchers detected brightenings from which ejections of hot material from the surface of the star could be observed.
The third one says that the brightenings were noticed where there was the presence of strong magnetic fields. This explanation was based on satellite observations.
However, the researchers could not find explanations for radio brightenings in some other areas.
"The other sources used did not explain the cause of the brightening. We don't know what causes those phenomena. We must continue our research," Kallunki says.
The peer-reviewed research article was published in Solar Physics.