Scientists have used a 40-year dataset from the Birmingham Solar-Oscillations Network (BiSON) to study the Sun's internal vibrations during its quiet solar minimum periods. Their analysis revealed a stronger acoustic "glitch" during the 2008-2009 minimum, indicating subtle structural changes, like a slightly hotter outer layer, during that time of low magnetic activity.
The findings confirm that the Sun does not return to an identical state after each 11-year cycle, with its activity varying over decades and centuries. This research provides new insights into the Sun's internal dynamics and is a first step in understanding the long-term changes in how the Sun generates its magnetic field.
The main topics covered are solar cycles and minima, asteroseismology (studying stellar interiors via oscillations), long-term solar behavior changes, and the analysis of specific acoustic glitches within the Sun.