Stéphane Mathis

A star like the Sun hums like a bell: sound waves inside make its surface tremble ever so slightly. From this trembling, astronomers, like doctors reading a pulse, infer the star's temperature, density, and age. But the Kepler telescope spotted an oddity: many stars that spin fast and are covered in spots show no trembling at all. It's as if they've lost their voice.

Red giants are swollen, aging stars. Deep inside, an ocean of plasma churns: heat forces its way from the core to the surface, generating waves like a mighty surf. The star's magnetic field acts like an invisible seabed – it steers these waves, changing their height and speed.