Artists depiction of a white dwarf orbiting the supermassive black hole 1ES 1927+654Aurore Simonnet/Sonoma State UniversityStrange vibrations emanating from a supermassive black hole appear to be growing more frequent and they could be caused by a white dwarf star orbiting perilously close to its event horizon.In 2018, a supermassive black hole called 1ES 1927+654 took astronomers by surprise by changing from a relatively inactive black hole to an extremely bright one. It was the first time a supermassive black hole had been observed changing in this way.