Astronomers decode black holes’ ‘ringing’ to test Einstein’s theory
Think of black holes as bells from the cosmos. When they collide and coalesce, the resulting black hole “rings” like a bell, with vibrations known as quasinormal modes (gravitational-wave frequencies that decay in amplitude during the ‘ringdown’ phase). These are not just ghostly echoes. They are unambiguous probes of black hole mass and spin. They…