The Sun, now halfway through its life, might be slowing its magnetic activity, researchers say, which could lead to permanent changes in the sunspots and auroras we see. The Sun has changed its figure, researchers say, and might keep it that way. The structure of the Sun's surface, where sunspots live, appears to have changed markedly 23 years ago. That's when solar magnetic activity might have started slowing down, Rachel Howe (University of Birmingham, UK, and Aarhaus University, Denmark) and collaborators speculate in paper to appear in the Monthly Notices of the Royal Astronomical Society (full text here). Such a structural change might help explain the Sun's mysteriously weak cycles in recent years. The interior of the Sun pulsates as rhythmically as a human heart. But while the heart pulses at one fairly steady frequency, the Sun reverberates at thousands of different frequencies. Pressure changes inside the Sun create these reverberations, just like pressure changes in the air