Variable sunshine— researchers explain why our Sun’s brightness fluctuates

The Sun shines from the heavens, seemingly calm and unvarying. In fact, it doesn’t always shine with uniform brightness, but shows dimmings and brightenings. Two phenomena alone are responsible for these fluctuations: the magnetic fields on the visible surface and gigantic plasma currents, bubbling up from the star’s interior. A team headed by the Max Planck Institute for Solar System Research in Göttingen reports this result in today’s issue of Nature Astronomy. For the first time, the scientists have managed to reconstruct fluctuations in brightness on all time scales observed to date – from minutes up to decades. These new insights are not only important for climate research, but can also be applied to distant stars. And they may simplify the future search for exoplanets.