How a Black Hole Amplifies Gravitational Waves ✎ express
In the usual picture, a black hole is a featureless pit in spacetime. But if a shell of matter vibrates around it, the gap between the edge of the abyss and this shell becomes a resonant cavity. Any external perturbation, even the slightest, triggers oscillations in an invisible field permeating the vacuum. Step by step, like a pendulum pushed in rhythm, the field gains energy, and a tiny nudge turns into a loud signal. Eventually, the accumulated energy produces a noticeable secondary gravitational wave. It arrives delayed and amplified many times — an acoustic echo of the abyss. This mechanism explains why even minuscule additions to gravity theory can yield a loud response: the black hole acts like a giant musical instrument, turning a soft sound into a powerful chord.
The field energy can grow tens of times over a few oscillation cycles, turning the whisper of external disturbances into a loud signal.