A Question

A Black Hole Merger

In the model of General Relativity, gravity and light travel at the same velocity. In September of this year the Virgo gravitational-wave detector in Italy made its first detection of ripples in the fabric of the universe when two black holes merged together, warping the space around them and creating gravitational waves that rippled through the universe for 1.8 billion years before reaching us here on Earth.

Theories and models state that once something is beyond the event horizon of a black hole, nothing — not even light — can escape the extreme gravitational forces of the ultra-dense object. But how about gravity? Can gravitational waves ripple from inside the event horizon of a black hole out, or does physics prevent it?