What happens when a gravitational wave meets a black hole? | by Ethan Siegel | Starts With A Bang! | Dec, 2024
Gravitational waves are the last signatures that are emitted by merging black holes. What happens when these two phenomena meet in space?
When two things in the Universe that “always” occur meet one another, how do you know which one will win? Gravitational waves, for example, always pass through whatever they encounter: empty space, dark matter, gas clouds, plasma, dust, planets, stars, and even dense stellar remnants like white dwarfs and neutron stars. They carry energy, which they can deposit into objects they affect, deforming and distorting space (along with everything in it) as they pass through. Nothing ever seems to stop gravitational waves, with the only alterations to “unperturbed propagation” coming from the effects of distorted spacetime due to the presence of masses and the expanding Universe.
But on the other side of the coin, we have black holes, which have an event horizon: a region from within which nothing can escape. So when the immovable object meets the irresistible force, who wins? While gravitational waves can be emitted from outside the event horizon of merging black holes, if something takes place inside the event horizon, it cannot escape. So what happens, then, if a propagating gravitational wave…
